how do zoos aid in animal research

Research in the modern Zoo

Zoos have come a long way from their beginnings as menageries in the 19th century. Rather than showcasing exotic animals purely for profit and entertainment as early zoos did, modern accredited zoos are active participants in scientific research and wildlife conservation. Research and conservation go hand-in-hand: in order to protect wild animals and their habitats, we need to understand these animals and the threats they face. Our mission at Zoo Atlanta – to save wildlife and their habitats through conservation, research, education, and engaging experiences – drives our contributions to these efforts. Read on to find out how to connect your students to current research and inspire conservation action within your classrooms.  

There are two broad types of wildlife research: in-situ research and ex-situ research. In-situ research is conducted out in the wild. This type of research can directly study the threats facing wild animal populations. It allows scientists to monitor and evaluate animal behavior, population dynamics, and ecosystem processes. The benefit of this type of research is that you are studying wild animals in their wild habitats. 

Ex-situ research is that which takes place outside of an animal’s natural habitat, such as here at the Zoo. This type of research can focus on topics like veterinary medicine, animal training, and individual animal personalities and behavior. Ex-situ research allows researchers to study animals up close and evaluate individual animal behaviors, development, and physiology. Ex-situ research can help conservation efforts that help protect wild animals and their habitats by providing information that would be difficult to obtain in the wild. It also helps zoos learn how to take better care of their animals. 

Zoo Atlanta participates in both in-situ and ex-situ research projects. In-situ research efforts are conducted through field work by zoo teammates and by providing support for the research projects of trusted partners. One effort we have participated in is the discovery and  naming of new species of amphibians . Dr. Joe Mendelson, the Director of Research at Zoo Atlanta, is heavily involved in these efforts and argues that taxonomy is “central to our understanding of the planet and central to our efforts to conserve our increasingly threatened biodiversity.” The Zoo partners with the Central Florida Zoo’s Orianne Center for Indigo Conservation and Auburn University to track and monitor re-released  eastern indigo snakes , many of whom were reared at Zoo Atlanta, in the Conecuh National Forest. We also work closely with the  Dian Fossey Gorilla Fund International , an organization devoted to researching and protecting gorillas in Rwanda and the Democratic Republic of Congo. One of our flagship projects focuses on studying a deadly fungus that has caused  Panamanian golden frogs  to become extinct in the wild. We care for a small population of these frogs at the Zoo with the hope that they can one day be re-released into the wild.  

Zoo Atlanta also conducts many ex-situ research projects on Zoo grounds. As one of the only zoos in the United States to house giant pandas, we have been able to  study giant panda  maternal behavior and sensory perception. These studies can help zoos take better care of panda cubs and provide better enrichment for pandas, while also providing insights that may aid wild panda conservation. The Zoo is the headquarters for the  Great Ape Heart Project , which aims to understand heart disease in great apes such as gorillas, orangutans, bonobos, and chimpanzees. The project studies the causes, diagnosis, and treatment for heart disease in great apes. We also collaborate with researchers from Georgia Tech to study how  elephants can use their trunks  to delicately pick up objects and suck in large amounts of water.  Veterinary medicine ,  Komodo  dragon genome  sequencing, and  sidewinder snake  movement and biodesign are just a few of the other ex-situ research projects that Zoo Atlanta participates in. 

Both in-situ and ex-situ research efforts are vital to wildlife conservation. Zoos are particularly well-situated to conduct ex-situ research, which makes them valuable partners to conservation organizations seeking to learn more about how to protect wild animals. They also support in-situ research projects by contributing money, providing staff and expertise to assist with these efforts, and educating the public about the value of research. You and your students can learn more about Zoo Atlanta’s research efforts by visiting the  Research  section on our website or reading  Beyond the Zoo , which outlines more ways that Zoo Atlanta contributes to wildlife research and conservation efforts. Advanced students who are interested in pursuing biological research can peruse our list of  Zoo Atlanta scientific publications . If you want to visit the Zoo, meet some of the animals we care for and study, and talk to knowledgeable Zoo Atlanta staff members, check out our  Teacher Resources  to start planning your trip

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Article Contents

Types of collections, benefits of collaboration, challenges to collaboration and integration, actions moving forward, conclusions, acknowledgments.

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Bridging the Research Gap between Live Collections in Zoos and Preserved Collections in Natural History Museums

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Sinlan Poo, Steven M Whitfield, Alexander Shepack, Gregory J Watkins-Colwell, Gil Nelson, Jillian Goodwin, Allison Bogisich, Patricia L R Brennan, Jennifer D'Agostino, Michelle S Koo, Joseph R Mendelson, Rebecca Snyder, Sandra Wilson, Gary P Aronsen, Andrew C Bentley, David C Blackburn, Matthew R Borths, Mariel L Campbell, Dalia A Conde, Joseph A Cook, Juan D Daza, Daniel P Dembiec, Jonathan L Dunnum, Catherine M Early, Adam W Ferguson, Amanda Greene, Robert Guralnick, Courtney Janney, Debbie Johnson, Felicia Knightly, Stephane Poulin, Luiz Rocha, Pamela S Soltis, Barbara Thiers, Prosanta Chakrabarty, Bridging the Research Gap between Live Collections in Zoos and Preserved Collections in Natural History Museums, BioScience , Volume 72, Issue 5, May 2022, Pages 449–460, https://doi.org/10.1093/biosci/biac022

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Zoos and natural history museums are both collections-based institutions with important missions in biodiversity research and education. Animals in zoos are a repository and living record of the world's biodiversity, whereas natural history museums are a permanent historical record of snapshots of biodiversity in time. Surprisingly, despite significant overlap in institutional missions, formal partnerships between these institution types are infrequent. Life history information, pedigrees, and medical records maintained at zoos should be seen as complementary to historical records of morphology, genetics, and distribution kept at museums. Through examining both institution types, we synthesize the benefits and challenges of cross-institutional exchanges and propose actions to increase the dialog between zoos and museums. With a growing recognition of the importance of collections to the advancement of scientific research and discovery, a transformational impact could be made with long-term investments in connecting the institutions that are caretakers of living and preserved animals.

Animal collections are a repository of our shared biodiversity and a valuable resource of scientific research and discovery (Dick 2017 , Miller et al. 2020 ). Natural history museums hold preserved biodiversity collections and associated specimen and ecological data that have long been recognized as an invaluable and irreplaceable resource for biodiversity research and society (Johnson et al. 2011 , McLean et al. 2016 , Funk 2018 , Nelson and Ellis 2019 , Watanabe 2019 , Lendemer et al. 2020 , NASEM 2020 ). Zoos and aquariums (hereafter, we use zoos to refer to both zoos and aquariums) hold living collections of animals and associated data on life history, demographics, pedigree (genealogy), genetics, physiology, morphology, and behavior but are not typically recognized for their value for biodiversity research (see Zehr et al. 2014 for exceptions, but see Conde et al. 2019 , NASEM 2020 ). Despite the potential for synergy that is apparent in the complementary and nonoverlapping specimen and data types held in zoos and natural history museums, formal partnerships between these two institution types are uncommon.

In the present article, we highlight how potential collaborations could enhance the value of both types of collections and advance collective missions of biodiversity conservation, research, and education. We begin by describing the types of collections and associated data held by each institution, with a particular focus on potential complementarity among types of specimens and data. We then describe benefits of collaboration to each institution type, highlight case studies of existing productive collaborations, and identify best practices for collaborations. We address logistical challenges to integrating collection types, including needs in human and cyberinfrastructure and differences in cultures and values between institution types. We conclude with a list of action steps that institutions can take to link and leverage biological collections to advance biodiversity research.

Biological collections can take various forms and encompass different geographic and taxonomic scales.

Living collections and associated data in zoos

Institutions accredited by the Association of Zoos and Aquariums (AZA) hold roughly 800,000 living animals, primarily in the United States (table  1 ; AZA 2021b ). These collections are strongly biased toward vertebrates and, in particular, birds and fish (Conde et al. 2019 , Rose et al. 2019 ). Globally, zoos use a variety of collections software, with at least three million records digitized worldwide within the Species360 management system alone (Species360 2021 ), representing more than 21,000 species. In addition to living animals, zoos hold extensive records for each animal, starting with birth or transfer from the wild. Zoos record information on taxonomy, animal demography, and pedigrees, and they maintain longitudinal information on health, physiology, life history, behavior, and husbandry protocols used during the animal's life such as diet, veterinary treatments, and social groupings. As a part of routine health assessments, conservation breeding programs, or internal and external research projects, zoos periodically collect and preserve biological materials (whole blood, plasma, serum, DNA, gametes, etc.). Usually, zoos store these biological materials on site, either for the short or long term, depending on storage space and the conservation priority of the species. Typically, biobanks are not coordinated among institutions, but the recently launched European Association of Zoos and Aquaria biobank is an example of coordinated sample storage and coordination (Pérez-Espona 2021 ). In the event of an animal's death, the institution performs a thorough necropsy (Griner 1983 , Terio et al. 2018 ), after which the physical specimen is usually destroyed through incineration or other means. The other biological materials associated with the animals are sometimes maintained and stored after the death of the organism; however, the storage and maintenance of these materials are highly variable and dependent on each institution's own policies.

Characteristics of collections and specimen data from natural history museums and zoos.

For animals currently living within the collection, digital records are updated constantly using management software, such as ZIMS, Tracks, PopLink, or similar software (Cohn 2006 , Faust et al. 2019 ). This information is continuously recorded during an animal's life, which is a major difference from records kept at natural history museums, and is maintained in perpetuity after the animal's death. Within AZA-accredited zoos, information typically is shared. This is necessary for the effective management of the entire captive population, which is seen as a single unit despite the fact that individual animals may be spread out across multiple institutions. Each individual animal has a global accession number and one or more local identifiers. Collection management software tracks detailed husbandry data, pedigrees, and medical records. For animals that have died, records are kept digitally within the management software or, in cases of historical records prior to digitization, are kept on paper.

As the mission of modern zoos has evolved into one of conservation and species preservation, the composition of living collections in zoos has changed over time to reduce the percentage of wild-caught individuals and, correspondingly, to increase the number of captive-born animals. Moreover, zoos have increased their focus on rare or endangered species in need of conservation efforts (Conde et al. 2013 , Tapley et al. 2015 ) and have taken on larger numbers of nonreleasable animals from wildlife rehabilitation centers or confiscations from illegal trade (Fa et al. 2011 ). With each of these shifts, there is a corresponding effect on the scientific value of a collection's animals. For wild-caught animals, locality data may be of use, whereas captive-born animals can provide insights into genetics, health, and pedigree. Increased holdings of at-risk species that may be inaccessible elsewhere and rehabilitation of endangered species that are deemed “nonreleasable” provide the opportunity for research into animals that are in need of human intervention.

Preserved natural history collections in museums

Natural history museums hold roughly 500,000,000 to one billion biological specimens in US collections and three billion worldwide (table  1 ; NASEM 2020 ). These can be whole organisms (typically for smaller animals) or parts of those organisms (e.g., skins, skeletons, DNA, tissue, and associated ecto- and endoparasite samples). Natural history specimens typically include locality data, taxonomy, the collection date, and the collector, as well as information on the treatment (i.e., the method of preservation) of the specimen. Generally, the information available on a specimen in a natural history museum begins with a collection event in the field that results in the attainment of specimens. Once the initial specimen information is obtained, it can then be extended through various lenses (e.g., archaeological, paleontological, geological, societal, or taxonomic). Because specimens are normally euthanized for natural history research, the collection of information during the life of the animal is generally limited. Typically, natural history collection records only represent a single instance in the time of the animal's life—specifically, the period just before its death. However, it presents a transition to research that requires preserved specimens.

Specimen data are held in a range of collection management software platforms, such as Specify, Arctos, EMu, and Symbiota. Unlike in zoos, specimen data are typically not shared across institutions through the collection management software itself. Rather, collection management software platforms frequently use a consistent metadata standard (e.g., the Darwin Core), which allows data interchange (Wieczorek et al. 2012 ). In recent decades, museums have dramatically expanded the digitization and accessibility of specimen data, which has profoundly enhanced the value of specimens for biological research (Nelson and Ellis 2019 , Hedrick et al. 2020 , Miller et al. 2020 ). Data aggregators, such as VertNet, GBIF, DiSSCO, and iDigBio, provide access to collection information across institutions and software platforms and have, along with local institutional web portals, made collection information and specimen details increasingly publicly accessible (Constable et al. 2010 ). The digitization of museum records is an ongoing process, but to date, less than 40% of the specimens in US collections are represented online, with a substantial portion of specimen information remaining to be digitized.

Closer collaboration between zoos and natural history museums has clear benefits to both parties (figure  1 ).

Zoos and museums can maintain robust sharing networks across the United States. The Yale Peabody Museum of Natural History has received specimens from zoos across the US (network shown in orange), whereas the Oklahoma City Zoo has shared samples and specimens with universities and museums (network shown in blue). Both zoos and museums can maintain robust local and country-wide networks.

Benefits to zoos

Zoos typically do not have storage facilities or trained staff to curate preserved specimens in perpetuity. Instead, disposal of specimens is a logistical necessity and often a legal necessity, because of permitting or ownership requirements. As an alternative, if zoo specimens of high scientific value are deposited in natural history museums postmortem to become permanent specimens, this may lead to retrospective health information (figure  2 ) and genetic studies that could potentially contribute to assisted reproductive technologies that would benefit zoo collections in the future. Moreover, by extending the scientific lifespan of animals after death, zoos increase the usefulness of their collections and credibility as conservation-oriented and scientific organizations (figures  3 and  4 ; Miller et al. 2004 , Loh et al. 2018 ). This is particularly important for zoos accredited by the AZA, which has placed increasing emphasis on the need to invest in scientific advancement through basic and applied research (Rose et al. 2019 , AZA 2021a ). Collaborating with museums and having museums report back to zoos (or the AZA) about the impact of linking zoo animals with museum specimens would help to raise awareness of the added value of depositing zoo animals in museums and to help zoos articulate to supporters how their animals go on to promote science and conservation after their death. This kind of reciprocal illumination could aid in producing more fruitful collaboration between these institutions.

An Asian elephant from the Oklahoma City Zoo passed away from unknown causes (global accession no. 21,517,980). After the Museum of Osteology (also in Oklahoma) prepared the specimen as a skeleton and found affected and deformed molars, that diagnosis was determined to be the cause of death. The zoo now uses new dental monitoring techniques on its elephants because of this interaction with the museum. Photograph: Jennifer D'Agostino.

One example of a collections management system that can connect living and preserved specimen databases is the Arctos Collection Management system, a web-based multi-institutional collection management platform that currently handles thousands of records of specimens and biosamples from zoo–museum collaborations. Arctos museum records can be reciprocally linked to any external URL, creating the potential to form direct links with zoo databases such as ZIMS. Linking data between museum collection records and zoo databases will allow tracking of samples and their usage over the lifetime of individuals and beyond across multiple facilities and institutions. Data approved for public access can be searched through the main Arctos portal at https://arctos.database.museum and through biodiversity aggregators such as GBIF, enabling sample, project, and trait-based queries to extend the value of these samples and data for future research. Image: Mariel Campbell.

Since 2010, the Sedgwick County Zoo (SCZ) has partnered with the Yale Peabody Museum of Natural History to provide materials for use in a wide range of scientific studies including CT scanning, morphology studies and genome sequencing. SCZ has contributed over 770 specimens and samples to the Museum, including tissues and carcasses representing taxa from Gymnophiona to Proboscidea, and hopes to broaden communication with other potential partners to ensure maximum use of SCZ's resources. To date, specimens and tissue samples that the Zoo donated to the Museum have been used in more than 22 research projects and in university courses. Several SCZ specimens were scanned as part of the openVertebrate (oVert) Thematic Collections Network (NSF grant no. DBI-1,701,714), including YPM HERA 23,166 (Potamotyphlus kaupii), which is one of two specimens of the species (each from SCZ) used to fill in a vital taxonomic gap in the oVert sampling. Scan data and reconstructions are now available via MorphoSource for use by researchers and educators globally ( https://doi.org/10.17602/M2/M389815 , https://doi.org/10.17602/M2/M389823 ). Image reconstruction: Jaimi A. Gray. The image is a rendering of a 3D reconstruction created from CT scan of specimen YPM HERA 23,166. CT scanning done at Nanoscale Research Facility at the University of Florida, with a GE phoenix v|tome|x m 240 micro-CT scanner, and was funded by oVert TCN (NSF grant no. DBI-1,701,714). Segmentation and rendering performed using VG Studio Max (version 3.5.1).

Benefits to natural history museums

Museums receive clear benefits of expanding their collections with a deeper collaboration with zoos (figure  4 ). This includes not only whole or part of the physical specimen but also eggs or embryos, DNA, tissue, and other biological samples and accompanying information. Because many animals in zoos represent species that are rare, endangered, or even extinct in the wild, collecting new specimens from the field could be difficult, impossible, or potentially unethical. Furthermore, zoo specimens are typically accompanied by a lifetime of data on demography, behavior, reproduction, health, husbandry, and more. For smaller collections or collections used primarily for teaching, the broad diversity of species held by zoos may allow for considerable expansion of taxonomic representation in a collection, especially for nonmodel species. In addition, data collected from specimens of captive origin may be valuable to studies in which the taxon would otherwise be lacking (figure  5 ). Natural history museums would certainly benefit from the rich life history records that zoos focus on, because these data are largely unavailable to the museum community.

Patricia Brennan has worked with dozens of collaborators from farms to zoos to acquire specimens that died in captivity and whose bodies are ultimately preserved at museums for posterity, with Brennan facilitating that exchange after she completes her research. These include specimens of snake hemipenes (Nerodia rhombifer; M1) that are inflated with vaseline (M2) and then made into 3D models (M3). Specimens such as these require careful postmortem handling of animals, including rapid preservation. The connections and collaborations necessary to obtain such specimens have not been easy to establish, particularly as it is not always clear whom to contact for this kind of work at these facilities and this collaborative work is not usually part of the research mission of these facilities. Photograph: Bernard Brennan. 3D Images: Genesis Lara Granados and Juliet Greenwood.

Current collaborative efforts

Existing collaborations between zoos and museums may illustrate shared opportunities and mutually beneficial relationships. In figures  1 – 4 , we show several examples of existing collaborations between zoos and museums and demonstrate a range of benefits for these collaborations. Although zoos and museums occasionally exchange specimens, samples, or data, these exchanges are still relatively infrequent and represent a very small percentage of the collection holdings of either zoos or natural history museums. When exchanges do occur, they are typically the result of connections between individual museum staff (collection managers or curators) and zoo staff (curators or veterinarians), instead of a systemic and long-term collaboration that is established between the institutions. Although the AZA accreditation guidelines encourage specimens to be deposited in natural history museums postmortem (AZA 2021a ), large-scale collaborations are typically not initiated by the leadership of zoos or museums or specifically by interinstitutional organizations (e.g., AZA, the Society for the Preservation of Natural History Collections, and other scientific societies). We recommend the staff at zoos and aquariums consider the long-term benefits of having a largely intact specimen (versus the destructive sampling of a full necropsy) for future study at a museum, when it is possible to do so. Even in cases in which the entire voucher specimen may not be available for depositing at museums, the tissue or DNA samples from these animals (along with the associated data) can continue to be a valuable resource (Buckner et al. 2021 , Card et al. 2021 , Thompson et al. 2021 ).

Zoos and natural history museums have distinct cultures, values, organizational structures, research agendas, data management systems, professional societies, and funding strategies. In addition, there are logistical challenges of linking two different types of institutions. These differences can create barriers to effective communication and productive collaborations, but articulating the differences clearly can help identify commonalities and focal points for collaboration. In the present article, we highlight some of the challenges to working across collection types, and identify actions to surmount these challenges.

Distinct institutional cultures and values

The underlying cultural differences between staff in zoos and natural history museums are multifaceted and complex, although they each hold at their core a passion and keen interest in biodiversity and the natural world. In the present article, we focus on several tangible and relevant elements of these differences such as different terminologies and attitudes toward specimens. Different terminologies used between institutions (box 1 ) can inhibit effective collaboration. Because of distinct and largely separate cultures, perceptions of one institution type by another may be outdated or erroneous. Making these misconceptions explicit and correcting them may help bridge cultures and find common institutional values and research objectives (see the “Different research priorities and agendas” section).

AZA. Association of Zoos and Aquariums, the primary organization that accredits zoos and distinguishes among modern zoos and roadside zoos or private animal collections. AZA requires high standards for animal care, recordkeeping, and engagement in scientific research.

Biobank. A repository for biological samples, typically for medical purposes.

Biocuration. Linking metadata about specimens so that information obtained from work with the specimens is retained or connected with the specimen's data in a digital framework.

Biofact. An artifact of organic origin (skull, fur, shell, horn, etc.), frequently used in zoos.

Cosmetic necropsy. Necropsy performed with minimal disruption to the body equal to a surgical incision. Often precludes full diagnostic value.

Conserve. Protect (something, especially an environmentally or culturally important place or thing) from harm or destruction.

Darwin Core. A body of data standards intended to facilitate the sharing of information about biological occurrences. Used by natural history museums, Darwin Core standards allow for data interoperability among software platforms.

Dynamic links . For example, a hyperlink between GenBank and a museum collection's database that would allow a user to find voucher information about the source of genetic data by clicking on a link. As opposed to static (unchanging) links that connect data repositories, which have a static catalog number that doesn't provide taxonomic or collection information and that cannot be automatically updated.

Extended specimen concept. A recent concept that a natural history specimen is more than a singular physical object, and instead that the specimen has extensions to potentially limitless additional physical preparations and digital resources.

iDigBio. Integrated Digitized Biocollections, the US National Resource and Coordinating Center for facilitating digitization and mobilization of information about vouchered natural history specimens. iDigBio aggregates specimen information from natural history collections across institutions.

MorphoSource. A digital repository of three-dimensional models of biological specimens.

Noninvasive research. Research that does not involve physical harm or distress to a living animal or specimen, i.e., photography or sound recording of living animals, CT scanning of preserved specimens.

Preserve. To safeguard and store the body, or parts of the body, of an organism, typically with a “preservative” such as ethanol and formalin or taxidermy, and associated data for future study.

Species360. A nonprofit NGO that produces ZIMS software, a database used by zoos to collect and store information on animals in zoo collections.

Specimen. A live or preserved organism (part of an organism) housed in a collection.

SPNHC. The Society for the Preservation of Natural History Collections.

SSP. Species Survival Plan Programs, AZA's programs to cooperatively manage ex situ populations for long-term sustainability.

TAG. Taxonomic Advisory Group, AZA's organized groups of taxonomic specialists who guide and facilitate cooperative animal management and conservation programs.

Voucher. A permanently preserved specimen deposited in an accessible collection.

ZIMS. Zoological Information Management Software, a software platform created by Species360 used by many zoos for collection and management of live animal collections.

One major critical distinction between the values of zoos and museums is an affective attachment to living animals in zoos (Hosey and Melfi 2012 ), to which there is little to no apparent analog in museums. Through close daily interaction with individual living animals, long-term bonds between zoo staff and the animal they care for can be formed (Meehan et al. 2016 ). Such affection toward a specimen is rarely demonstrated for preserved museum specimens by museum staff. Comparatively, in museums, care for and attachment to specimens takes on several different forms: performing regular preventative conservation and maintenance; ensuring that specimens used for research are not damaged in such a way that could negatively affect their integrity; and ensuring that specimens are properly identified, and cataloged and that they have data that is made accessible to the public and researchers. In many cases, the history of the specimen tells a story that appeals to museum staff and may lead to some genuine attachment to the specimen and its story (such as who collected it, how long ago it was collected, whether it is a type specimen used to describe a new species, etc.). The sense that a specimen represents the past, but can be used into the future often leads to a great sense of responsibility among museum staff, who realize that their work today affects its usefulness in the future including in ways that are yet to be discovered or realized (NASEM 2020 ).

Different research priorities and agendas

The research priorities and agendas of zoos and museums vary, both in terms of their history and involvement in research and in terms of their research focus. Although both institutions may be involved in research, there is a longer history of scientific research and discovery within museums that may have aided in the development of more research-centric views in their institutional mission, whereas more emphasis is given to animal health and welfare within zoos. Museums typically list the contact information of curators and researchers openly on their websites, making research requests and collaboration relatively easy for users (e.g., other scientists interested in collections, members of the public). In comparison, the process of gaining access to information on zoo collections is less clear, and contact information is not readily available for most zoo collections.

In terms of research focus, collection-based research at natural history museums tends to have a wider focus, including basic biology (e.g., anatomy, biogeography, taxonomy, and systematics), evolution (Funk 2018 ), and more applied research (e.g., conservation and global change, Johnson et al. 2011 , emerging infectious disease, Dunnum et al. 2017 , Cook et al. 2020 , Colella et al. 2021 , Thompson et al. 2021 ). In contrast, several recent studies have reviewed research areas targeted by zoos, which illustrate most publications focus on applied research, such as animal sciences, behavior, cognition, husbandry, reproductive biology, welfare, veterinary care, or field conservation (Loh et al. 2018 , Rose et al. 2019 , Hvilsom et al. 2020 ). Museums also largely serve a research community outside of their walls, through specimen loans and, ever more frequently, digital data (e.g., CT scans online). Although zoo research also extends beyond the boundaries of the footprint of the institution, zoo collections are largely inaccessible to the broader research community.

Some museums may consider zoo specimens of low scientific value, because of the lack of locality data (i.e., the coordinates associated with the source population), possible effects of captivity on phenotypes (O'Regan and Kitchener 2005 , Hartstone-Rose et al. 2014 , Zack et al. 2021 ), potential adaptations to captivity (Williams and Hoffman 2009 ), hybridization of recognized or unrecognized taxa in breeding programs (Witzenberger and Hochkirch 2011 ), or necropsy practices. Although these issues may alter some aspects of the scientific value of specimens, there is considerable new research potential in using specimens from zoo collections to understand life history and demographics (Conde et al. 2019 ), to assess and predict the success of ex situ breeding and conservation translocation programs (Poo and Hinkson 2020 , Poo et al. 2021 ), and for diverse downstream genetic and biochemical analyses (Witzenberger and Hochkirch 2011 ). In addition, the use of zoo specimens in systematics or anatomical studies, among others, is still of significant value, given the rarity of some taxa in the wild or the lack of availability of wild-origin specimens in museum collections. In other words, the benefits of using a zoo animal may outweigh the potential effects of captivity or the lack of locality data.

Another example of distinct research agendas (and agendas in potential conflict) involves destructive necropsies. When a zoo animal dies, there is a critical internal research need and institutional responsibility to conduct a detailed necropsy to determine a cause of death (Griner 1983 , Terio et al. 2018 ). These necropsies are necessary in captive populations, because identifying the cause of death can lead to the prevention of similar issues arising in the remaining zoo population. In contrast, destructive necropsy can make some specimens less valuable to natural history museums, because it interferes with the study of morphology. However, for some taxa, a sample of tissue or blood alone may be invaluable to museums for future research, although it is important to consider that broad sampling of different tissue types may permit organ- or disease-specific sampling or unanticipated research by a broader range of interested parties. In addition to taking potential steps to reduce the destructiveness of necropsies for zoo specimens that are intended for museum transfer, improved communication and collaboration efforts on both sides would work to align research agendas to maximize the value of specimens to both zoos and museums.

Separate and nonoverlapping data management systems

The digitization and integration of biodiversity collection data have opened vast frontiers in scientific discovery (Conde et al. 2019 , Nelson and Ellis 2019 ). Although both zoos and museums hold digitized data in sophisticated data management systems (Cohn 2006 , Nelson and Ellis 2019 ), zoo and museum data are not currently integrated. Moreover, although both types of institutions purchase collections management software, those designed for natural history collection data are generally integrated with community science platforms that are publicly accessible through data aggregators, whereas those used in zoos are not accessible to the public or the larger scientific community through data aggregators or other means.

Legal, political, and ethical barriers to collaboration

There are significant institutional barriers that can prevent effective collaboration. The ownership of individual animals in zoo collections is complex; individual animals may belong to the zoo where they live; may be on loan from another institution; or may be owned by state, federal, or foreign governments. A zoo that is holding an animal may require permission from the owning institution to provide samples to other institutions (even those collected noninvasively), and in some cases, the terms of a loan or holding rights may preclude the collection of samples from an animal or require the destruction of the specimen following its death. Although zoo animals that are of high scientific value may be worth these regulatory obstacles, advance planning may often be required long before the collection of samples from a zoo specimen or transfer of a deceased animal to a museum. Some foresight in negotiating these agreements may go a long way to negating these issues.

Hostility toward zoos by animal rights activists may also prevent sharing sensitive zoo data, including data related to primates, cetaceans, and elephants (Hosey et al. 2020 ) and other charismatic fauna. Some staff or administrators at zoos may feel that the nature—or the very existence—of their institutions and jobs are threatened by animal rights activists (Norton et al. 2012 ). Although the AZA has high standards of animal care that are continually raised and updated, there is concern that bad actors will seek to misrepresent any data and specimens that zoos make available. This alone may make many zoos reluctant to voluntarily share data on husbandry or medical records or even share samples or specimens from these sensitive groups.

Other regulatory barriers may exist in the forms of institutional animal care and use committee protocols, the Nagoya Protocol, and various permitting regulations including the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service, the Endangered Species Act, the Convention on International Trade in Endangered Species, and the Migratory Bird Treaty Act, as well as biosafety and chemical safety regulations. The Nagoya Protocol itself may prevent the transfer of genetic resources (including samples or genetic data) without reference to the original permit or explicit permission from the country of origin. Even the physical process of transferring a sample will have regulatory concerns related to the International Air Transport Association, the USDA, or the US Department of Transportation, and possibly others. In general however, both zoos and museums are required to abide by many of the same laws and regulations, despite the change of some of these issues at the time of the animal's death. Navigating the regulatory labyrinth is key to successful collaboration. Although substantial obstacles may exist, given the degree of overlap in regulatory oversight, such navigation is not insurmountable. In fact, collaborating with museums with more experience with and infrastructure in shipping preserved specimens may benefit zoos; likewise, collaborating with zoos that have high standards of animal care and welfare could benefit museum staff that are collecting, handling, and euthanizing animals in the field.

Increasing the connection between zoos and museums requires concrete steps to be taken to link their digital data, transfer physical specimens across institutions, and create a shared, collaborative, research culture.

Data link and data accessibility

Both zoos and natural history museums have extensive databases critical to the holistic understanding of animal biodiversity (Suarez and Tsutsui 2004 , Cohn 2006 , Conde et al. 2019 , Heberling 2020 ). Although the databases are currently not connected, the opportunity to link their data exists through the Darwin Core metadata standards (Wieczorek et al. 2012 ), which would permit greater integration of data. Although it may not be possible to fully integrate zoo and museum databases using existing infrastructure, integrating data under a common format is certainly an achievable goal in the near future. A shared data language standard will ultimately lead to connecting the information of living and preserved specimens.

Although zoos are understandably reluctant to make sensitive animal data public, the collection management software used by zoos could offer public access to limited data—at a minimum, as a list of species held by an institution or the number of individuals currently held for each species with their accession numbers. Given the public nature of many zoos, some of this information (e.g., the number of species and individuals) is already present for visitors to see and, therefore, sharing such information should not be controversial. Even this basic level of transparency would allow scientists anywhere with research needs to be able to find zoos that hold animal species they might find useful for noninvasive research projects. This level of accessibility would also allow natural history museums to search for individuals at zoos and make requests for tissues or to arrange for transfer of specimens to research collections at the end of an animal's life. We have found that one of the most common frustrations among zoo and museum researchers is not knowing whom to contact at the other institution type in order to begin a collaboration (figure  5 ). Having a website or accessible documentation listing the various roles and contact information for researchers would help facilitate valuable cross-institutional collaborations. We recommend that at least one email address (potentially anonymized for sensitivity) be a dedicated contact for research inquiries. Although it is possible that unwanted inquiries may occur when contact information is made public, the benefits likely outweigh the potential costs. We suggest, as a more localized first step, that zoo and museum staff in relatively close proximity reach out to one another to open lines of communication; we also suggest that interested zoo and museum researchers build coordination and collaboration networks to better address some of the issues raised in the present article.

Specimen and accompanying data transfer

Natural history museums have the capacity to preserve animal specimens, samples, and data in perpetuity. Many zoo animals have high scientific value as living or preserved specimens: rare or endangered animals that cannot be responsibly collected in the wild today, populations destined for reintroduction programs (especially those from which DNA or germlines can be stored for future use; e.g., in long-term longitudinal studies of population genetics), or individuals that have been intensely studied during their lives that can serve as important vouchers for future study. The transfer of specimens from zoos to museums can be divided into two categories: during an animal's lifespan (tissues, blood, DNA , gametes) and postmortem (skeleton, organ, whole specimen). In the former case, collections space within museums can provide a long-term repository permitting the use and study of these samples along with the many other “wild” collections made by these institutions from natural history fieldwork. In the latter case, transfer of animals to natural history museums postmortem would allow research in these individuals to continue for decades or centuries, including research that could help protect and restore biodiversity in the future. To minimize physical damage to zoo animals during postmortem examinations, “cosmetic” necropsies can be performed to preserve the integrity of the scientific specimen. Although less destructive pathology techniques would be valuable, museums are also accustomed to finding great value in some field-collected specimens in less than pristine condition, including highly degraded road kills or specimens freed from the stomach contents of other preserved specimens (Hoving et al. 2013 , Hieb et al. 2014 ). When a zoo specimen is transferred to a natural history museum, both zoo and museum databases should cross-list unique identifiers (e.g., catalog or accession number), so that each institution can track transfer of the specimen. When possible, dynamic links that can allow information from both collection databases to be updated simultaneously should be used, these dynamic data links are for the benefit of both institution types and anyone searching for this information (figure  3 ).

Contributing to the extended specimen concept and greater accessibility

During the first two decades of the twenty-first century, biological specimen collections held in museums and academic institutions have been heavily affected by technological and collections-based innovations. The advent and rapid rise of digitization, for example, has resulted in huge numbers of digital replicas (e.g., CT scans, photographs) of physical specimens being made accessible online. This has led museum curators and collections managers to explore methods for linking their specimen records to related data within and outside of their institutions (e.g., related records from the same collecting event, GenBank records and other sources of genomic data, field notes recorded by collectors, and taxonomic treatments). The publication of The Extended Specimen (Webster 2017 ), follow-up work by the Biodiversity Collections Network (Lendemer et al. 2020 ), a National Academies biological collections report (NASEM 2020 ), and the Alliance for Global Biodiversity Knowledge Discourse consultation facilitated by GBIF (phase 1, www.gbif.org/event/2rUVeHayibJnajGOYgimja/digital-extended-specimen-first-phase-community-consultation , and phase 2, www.gbif.org/event/6FF3aaAHoIkD9JToJjN4Vw/digital-extended-specimen-2nd-phase-community-consultation ) have secured this concept in the literature and launched efforts to more precisely circumscribe the concept of turning a physical specimen into a linked and digitally extended specimen that would have added value for enriching biodiversity research.

The integration of zoo and museum data collected from a single animal is a fitting paradigm for the digital extended specimen concept. The data collected on living animals in zoos (e.g., blood and tissue samples, dietary patterns, behavioral repertoire, disease and illness records) may be far richer and more complete than museum specimens normally provide, especially for animals sampled across a lifetime. Assuming that zoo animals are deposited as specimens in natural history museums on their death, coupling records at these different institutes with bidirectional digital links ensures availability of these data to a broad range of researchers. These shared data can then be added to data aggregators (e.g., iDigBio, GBIF) that make these linked records even more widely accessible and underscore their important role in subsequent scientific efforts (Buckner et al. 2021 ). Specimens, living or dead, that have their metadata in databases will allow for a digital record to exist between the original collectors, caretakers, and curators. Likewise, these databases, when they are public, allow for accessibility that is often a barrier to equity when they are kept completely private. Some sensitive information may be restricted, but the more metadata that are publicly available and accessible, the more equitably the data can be used.

Bridging cultures

Bridging institutional cultures and creating a shared vision of how collections of living and preserved animals can be better integrated are key to advance scientific discovery of biodiversity as a whole. As zoos continue to build up their capacity for research (see AZA 2021a ), there is a clear desire within the research community of both zoos and museums to increase cross-institutional collaboration and exchange of ideas. Scientists from both institutions can make progress through collaborative workshops, shared training sessions, expanding the pipeline for students and younger researchers from diverse backgrounds to work in both settings and for grants to foster the establishment of cross-institutional networks. Ultimately, broad institutional support is needed for lasting change, but a good place to start is through invitations to give seminars, tours of the different facilities, and other exchanges that foster sharing ideas and research by both institution types. It is important to recognize that although there may be cultural differences between institutions, many zoos and museums share the same ultimate goal of conserving species in the wild for the future. Recognizing the idea of an extended specimen concept and acknowledging that the best way to honor an animal may be to preserve it for generations to come can help bridge the differing cultures of zoos and museums. Ultimately, the pathway to bridging cultures requires collaborative initiatives with representatives from both zoos and museums, the development of human connections, and mutual understanding and trust. Although such a pathway may not be easy to traverse, it holds transformative potential for institutions and their staff, for the collections in their care, and for their wild counterparts that both institutions seek to conserve in perpetuity.

Increased coordination between living collections of zoos and the traditional collections of natural history museums is a logical and mutually beneficial relationship. Although nascent collaborations exist that demonstrate the potential of coordination, we argue that the interactions among institutions are severely underdeveloped. We identified areas where the most immediate connections could realize near-term goals, including specimen transfer postmortem, data transfer postmortem, and permanent preservation of zoo specimens and associated data in natural history museums. Furthermore, we point to where a transformational impact could be made with long-term investments in bridging gaps between institutions, such as integrating zoo data with other biodiversity databases and expanding access to and the use of zoo data for biodiversity conservation and global change research. Ultimately, it will have to be the people who work at these institutions who bring cultural change by sharing their scientific ideals and approaches while creating personal connections that lead to collaborations and progress toward shared goals.

The present article was born in digital captivity out of the workshop “Linking and Leveraging Biological Collections: Zoos and Natural History Museums” hosted by iDigBio, Memphis Zoo, Zoo Miami, Yale Peabody Museum of Natural History, and University of Notre Dame and funded by the US National Science Foundation (under grant no. DBI-1547229). The images were provided by Bernard Brennan, Mariel Campbell, Jennifer D'Agostino, Genesis Lara Granados, Jaimi A. Gray, and Juliet Greenwood. Sinlan Poo and Steven M. Whitfield contributed equally to this work.

Author Biographical

Sinlan Poo, Allison Bogisch, Daniel P. Dembiec, Courtney Janney, and Felicia Knightly are affiliated with the Memphis Zoological Society, in Memphis, Tennessee, in the United States. SP is also affiliated with Arkansas State University, in Jonesboro, Arkansas, in the United States. Steven M. Whitfield is affiliated with Zoo Miami and with Florida International University, both in Miami, Florida, in the United States. Alexander Shepack is affiliated with the University of Notre Dame, in Notre Dame, Indiana, in the United States. Gregory J. Watkins-Colwell is affiliated with the Yale Peabody Museum of Natural History, in New Haven, Connecticut, in the United States. Gil Nelson, Jillian Goodwin, David C. Blackburn, Robert Guralnick, and Pamela S. Soltis are affiliated with the Florida Museum of Natural History and with iDigBio, in Gainesville, Florida, in the United States. Patricia L. R. Brennan is affiliated with Mount Holyoke College, in South Hadley, Massachusetts, in the United States. Jennifer D'Agostino and Rebecca Snyder are affiliated with the Oklahoma City Zoo, in Oklahoma City, Oklahoma, in the United States. Michelle S. Koo is affiliated with the Museum of Vertebrate Zoology, at the University of California, Berkeley, in Berkeley, California, in the United States. Joseph R. Mendelson III is affiliated with Zoo Atlanta and with the Georgia Institute of Technology, in Atlanta, Georgia, in the United States. Sandra Wilson is affiliated with the Sedgwick County Zoo, in Wichita, Kansas, in the United States. Gary P. Aronsen is affiliated with Yale University, in New Haven, Connecticut, in the United States. Andrew C. Bentley is affiliated with the University of Kansas, in Lawrence, Kansas, in the United States. Matthew R. Borths and Amanda Greene are affiliated with the Duke Lemur Center, in Durham, North Carolina, in the United States. Mariel L. Campbell, Joseph A. Cook, and Jonathan L. Dunnum are affiliated with the Museum of Southwestern Biology, in Albuquerque, New Mexico, in the United States. Dalia A. Conde is affiliated with Species360 and with the University of Southern Denmark, in Odense, Denmark. Juan D. Daza is affiliated with Sam Houston State University, in Huntsville, Texas, in the United States. Catherine M. Early is affiliated with the Science Museum of Minnesota, in Saint Paul, Minnesota, in the United States. Adam W. Ferguson is affiliated with the Field Museum, in Chicago, Illinois, in the United States. Debbie Johnson is affiliated with Brookfield Zoo, in Brookfield, Illinois, in the United States. Stephane Poulin is affiliated with the Arizona-Sonora Desert Museum, in Tucson, Arizona, in the United States. Luiz Rocha is affiliated with the California Academy of Sciences, in San Francisco, in the United States. Barbara Thiers is affiliated with the New York Botanical Garden, in New York, New York, in the United States. Prosanta Chakrabarty is affiliated with Louisiana State University, in Baton Rouge, Louisiana, in the United States; with the Canadian Museum of Natural History, in Ottawa, Ontario, Canada; with the American Museum of Natural History, in New York, New York, in the United States, and the Smithsonian National Museum of Natural History, in Washington, DC, in the United States.

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April 15, 2009

How Do Zoos Help Endangered Animals?

There are more to zoos than putting animals on display

Dear EarthTalk: Do zoos have serious programs to save endangered species, besides putting a few captives on display for everyone to see? -- Kelly Traw, Seattle, WA

Most zoos are not only great places to get up close to wildlife, but many are also doing their part to bolster dwindling populations of animals still living free in the wild. To wit, dozens of zoos across North America participate in the Association of Zoos and Aquarium’s (AZA’s) Species Survival Plan (SSP) Program, which aims to manage the breeding of specific endangered species in order to help maintain healthy and self-sustaining populations that are both genetically diverse and demographically stable.

The end goal of many SSPs is the reintroduction of captive-raised endangered species into their native wild habitats. According to the AZA, SSPs and related programs have helped bring black-footed ferrets, California condors, red wolves and several other endangered species back from the brink of extinction over the last three decades. Zoos also use SSPs as research tools to better understand wildlife biology and population dynamics, and to raise awareness and funds to support field projects and habitat protection for specific species. AZA now administers some 113 different SSPs covering 181 individual species.

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To be selected as the focus of an SSP, a species must be endangered or threatened in the wild. Also, many SSP species are “flagship species,” meaning that they are well-known to people and engender strong feelings for their preservation and the protection of their habitat. The AZA approves new SSP programs if various internal advisory committees deem the species in question to be needy of the help and if sufficient numbers of researchers at various zoos or aquariums can dedicate time and resources to the cause.

AZA’s Maryland-based Conservation and Science Department administers the worldwide SSP program, generating master plans for specific species and coordinating research, transfer and reintroductions. Part of this process involves designing a “family tree” of particular managed populations in order to achieve maximum genetic diversity and demographic stability. AZA also makes breeding and other management recommendations with consideration given to the logistics and feasibility of transfers between institutions as well as maintenance of natural social groupings. In some cases, master plans may recommend not to breed specific animals, so as to avoid having captive populations outgrow available holding spaces.

While success stories abound, most wildlife biologists consider SSP programs to be works in progress. AZA zoos have been instrumental, for instance, in establishing a stable population of bongos, a threatened forest antelope native to Africa, through captive breeding programs under the SSP program. Many of these captive-bred bongos have subsequently been released into the wild and have helped bolster dwindling population numbers accordingly.

Of course, for every success story there are dozens of other examples where results have been less satisfying . SSP programs for lowland gorillas, Andean condors, giant pandas and snow leopards, among others, have not had such clear success, but remain part of the larger conservation picture for the species in question and the regions they inhabit.

CONTACTS : AZA’s Conservation & Science Program, www.aza.org/Conscience .

EarthTalk is produced by E/The Environmental Magazine. SEND YOUR ENVIRONMENTAL QUESTIONS TO: EarthTalk , P.O. Box 5098, Westport, CT 06881; [email protected] . Read past columns at: www.emagazine.com/earthtalk/archives.php . EarthTalk is now a book! Details and order information at: www.emagazine.com/earthtalkbook .

• A-Z Publications

Annual Review of Animal Biosciences

Volume 11, 2023, review article, open access, the role of zoos and aquariums in a changing world.

• Rafael Miranda 1 , Nora Escribano 1 , María Casas 1 , Andrea Pino-del-Carpio 1 , and Ana Villarroya 1
• View Affiliations Hide Affiliations Affiliations: Instituto de Biodiversidad y Medioambiente (BIOMA), Universidad de Navarra, Pamplona, Navarra, Spain; email: [email protected] [email protected] [email protected] [email protected] [email protected]
• Vol. 11:287-306 (Volume publication date February 2023) https://doi.org/10.1146/annurev-animal-050622-104306
• First published as a Review in Advance on October 20, 2022
• Copyright © 2023 by the author(s). This work is licensed under a Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. See credit lines of images or other third-party material in this article for license information

Zoos and aquariums have evolved significantly. From their origins as enclosures for the mere entertainment of the public, these institutions have undertaken new functions responding to the biodiversity crisis and social demands. Modern zoos and aquariums have the opportunity to educate people, contribute to species conservation, and produce animal-related research. However, there is increasing criticism toward the outcomes of their actions and the holding of species in their facilities. This review offers an integrated analysis of the state of knowledge about the role that zoos and aquariums play today. It describes their performance regarding their conservation, education, and research functions, highlighting general patterns and offering future perspectives. It identifies some challenges common to all these institutions, concluding that the way they keep up with the ever-growing social and environmental expectations will be decisive hereafter.

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Unlocking Nature’s Secrets: How Zoos Drive Valuable Scientific Research

Table of Contents

A Captivating World of Zoos and Their Role in Scientific Research

Zoos have always been a source of fascination for people of all ages. The opportunity to observe and learn about various animal species up close is an experience that captivates and educates. However, beyond their role as entertainment venues, zoos also play a crucial role in driving valuable scientific research. They provide unique opportunities for studying and understanding various animal species, unlocking nature’s secrets in the process.

Unlocking Nature’s Secrets Through Zoos

Zoos have evolved over the years, with conservation becoming a primary goal. They have transformed into safe havens for endangered species, contributing significantly to conservation efforts. But their importance extends far beyond that. Zoos serve as living laboratories for scientific research, offering researchers access to diverse animal species and their natural behaviors. They also act as educational institutions, promoting awareness and understanding of wildlife conservation among the public.

Zoos’ Crucial Role in Driving Valuable Scientific Research

Zoos are not just places where animals are kept for display. They actively contribute to scientific research in several ways. By understanding the importance of zoos in conservation efforts, we can appreciate the significant role they play in driving valuable scientific discoveries.

Conservation as a Primary Goal of Modern Zoos

Modern zoos prioritize conservation as a primary goal. They work tirelessly to protect and preserve endangered species, ensuring their survival for future generations. Through breeding programs and reintroduction efforts, zoos provide a safe haven for endangered animals, helping to increase their population and prevent their extinction.

Zoos as Safe Havens for Endangered Species

Zoos act as sanctuaries for endangered species, offering them protection from habitat loss, poaching, and other threats they face in the wild. By providing a controlled environment, zoos can closely monitor and manage the well-being of these animals, ensuring their survival and contributing to their long-term conservation.

Zoos play a vital role in breeding programs, focusing on the reproduction of endangered species. Through careful selection and controlled breeding, zoos help increase the genetic diversity of these species, reducing the risk of inbreeding and improving their chances of survival. Additionally, zoos participate in reintroduction efforts, preparing animals for life in the wild and releasing them into protected habitats when they are ready.

Zoos are not just places of entertainment; they are invaluable contributors to scientific research. Through their conservation efforts, they protect endangered species and ensure their survival. As living laboratories, they provide researchers with unique opportunities to study animal behavior, physiology, and health. Moreover, they serve as educational institutions, inspiring the public and future generations of scientists and conservationists. The importance of zoos in scientific research cannot be overstated, and continued support and collaboration between zoos and research institutions are crucial for unlocking nature’s secrets and driving valuable scientific discoveries.

The Importance of Zoos in Conservation Efforts

Conservation has become a primary goal of modern zoos, as they strive to protect and preserve endangered species. Zoos serve as safe havens for these animals, providing them with a protected environment where they can thrive and reproduce. This is particularly crucial for species that are on the brink of extinction.

One of the key roles that zoos play in conservation efforts is through their breeding programs. These programs aim to increase the population of endangered species and prevent their extinction. By carefully managing breeding pairs and ensuring genetic diversity, zoos contribute to the long-term survival of these species. Additionally, zoos often collaborate with other institutions and organizations to reintroduce captive-bred animals back into their natural habitats.

Zoos also play a vital role in raising awareness about the importance of conservation. Through educational programs and exhibits, they educate the public about the threats faced by wildlife and the need for conservation efforts. Visitors to zoos gain a deeper understanding of the challenges faced by endangered species and the role they can play in their protection.

Moreover, zoos engage visitors through interactive exhibits that showcase the beauty and diversity of wildlife. These exhibits not only entertain but also inspire visitors to develop a connection with nature and become advocates for conservation. By fostering a sense of wonder and appreciation for the natural world, zoos inspire future generations of scientists and conservationists.

However, it is important to acknowledge the ethical considerations and challenges associated with zoo-based research. Balancing the welfare of animals with research objectives is a complex task. Zoos must ensure that their research practices are conducted responsibly and with the utmost respect for the well-being of the animals involved.

Addressing public concerns and controversies surrounding zoos is another challenge that needs to be addressed. Some individuals question the ethics of keeping animals in captivity, even if it is for conservation purposes. Zoos must be transparent in their operations and actively address these concerns to maintain public trust and support.

In conclusion, zoos play a crucial role in conservation efforts. They provide a safe haven for endangered species, contribute to breeding programs, and collaborate with research institutions to advance our understanding of wildlife. Additionally, zoos serve as educational institutions, raising awareness about the importance of conservation and inspiring future generations. While ethical considerations and challenges exist, the potential of zoos to unlock nature’s secrets and drive valuable scientific discoveries cannot be overlooked. Continued support and collaboration between zoos and research institutions are essential to ensure the long-term survival of endangered species and the preservation of our natural world.

Zoos as Living Laboratories for Scientific Research

Zoos have long been recognized as more than just places for entertainment and recreation. They serve as living laboratories for scientific research, providing unique opportunities for studying and understanding various animal species. In this section, we will explore the importance of zoos as living laboratories and the valuable contributions they make to scientific research.

Access to Diverse Animal Species and Their Natural Behaviors

One of the key advantages of zoos as living laboratories is the access to diverse animal species . Zoos house a wide range of animals, including those that are rare, endangered, or difficult to study in the wild. This allows researchers to observe and study these animals up close, gaining insights into their behavior, physiology, and ecology.

By studying animals in captivity, researchers can observe natural behaviors that may be difficult to observe in the wild. Zoos provide a controlled environment where animals can be closely monitored, allowing researchers to gather data on their feeding habits, social interactions, and reproductive behaviors. This information is crucial for understanding the natural history and biology of these species.

Studying Animal Behavior and Social Dynamics in Controlled Environments

Zoos offer a unique opportunity to study animal behavior and social dynamics in controlled environments . By observing animals in captivity, researchers can manipulate variables and conduct experiments that would be challenging or unethical to perform in the wild.

For example, researchers can study the effects of social hierarchy on animal behavior by observing animals in zoo exhibits. They can investigate how individuals interact with each other, establish dominance, and form social bonds. These studies provide valuable insights into the social structure and behavior of animals, which can have implications for conservation and management strategies.

Investigating Animal Physiology and Health through Veterinary Research

Another important aspect of zoos as living laboratories is their contribution to veterinary research . Zoos have dedicated veterinary teams that provide medical care to the animals in their care. This presents an opportunity for researchers to investigate animal physiology, health, and disease.

Veterinary research conducted in zoos can help identify and treat health issues in captive animals. It can also provide insights into the health and well-being of wild populations. By studying the physiology and health of animals in zoos, researchers can contribute to the development of medical treatments and protocols that benefit both captive and wild animals.

In addition, zoos often collaborate with research institutions and universities to conduct cutting-edge research in various fields, such as genetics, nutrition, and reproductive biology. These collaborations allow scientists to access state-of-the-art facilities and expertise, further enhancing the scientific value of zoos as living laboratories.

In conclusion, zoos serve as living laboratories for scientific research, offering unique opportunities to study and understand various animal species. They provide access to diverse animal species, allowing researchers to observe natural behaviors and investigate social dynamics. Zoos also contribute to veterinary research, advancing our understanding of animal physiology and health. Through collaborations with research institutions, zoos facilitate cutting-edge research in various fields. The scientific discoveries made in zoos not only benefit captive animals but also contribute to the conservation and management of wild populations.

Contributions of Zoos to Wildlife Research and Conservation

Zoos have made significant contributions to wildlife research and conservation efforts. Through collaborations with universities and research institutions, zoos have played a crucial role in advancing our understanding of animal cognition, communication, and intelligence. By studying diverse animal species in controlled environments, zoos have provided valuable insights into the natural behaviors, social dynamics, and physiological health of animals. These contributions have not only enhanced our knowledge but have also helped in the conservation of endangered species.

Collaborations with universities and research institutions

Zoos have established strong partnerships with universities and research institutions, fostering a collaborative environment for scientific research. These collaborations have allowed researchers to access zoo populations and conduct studies that would otherwise be challenging in the wild. By working together, zoos and research institutions have been able to gather data, analyze it, and publish scientific papers that contribute to the body of knowledge in wildlife research and conservation.

Advancements in understanding animal cognition and intelligence

One of the significant contributions of zoos to wildlife research is the advancement in our understanding of animal cognition and intelligence. Through various experiments and observations, researchers have been able to study the cognitive abilities of animals in zoos. These studies have revealed fascinating insights into the problem-solving skills, memory, and learning capabilities of different species. Such knowledge is crucial for developing effective conservation strategies and improving animal welfare in captivity.

Research on animal communication and language

Zoos have also played a vital role in studying animal communication and language. By closely observing animal behavior and vocalizations, researchers have been able to decipher the complex communication systems of various species. This research has shed light on how animals communicate within their social groups, establish territories, and convey important information. Understanding animal communication is essential for conservation efforts as it helps in identifying threats, monitoring population dynamics, and developing effective conservation plans.

In addition to these contributions, zoos have also been actively involved in breeding programs and reintroduction efforts. By providing safe havens for endangered species, zoos have played a crucial role in preventing their extinction. Through carefully managed breeding programs, zoos have successfully bred and reintroduced several species back into the wild. These efforts have helped in restoring populations and conserving genetic diversity, which is vital for the long-term survival of endangered species.

Overall, the contributions of zoos to wildlife research and conservation are invaluable. Through collaborations with universities and research institutions, zoos have advanced our understanding of animal cognition, communication, and intelligence. By studying diverse animal species in controlled environments, zoos have provided valuable insights into their natural behaviors and physiological health. Additionally, zoos have actively participated in breeding programs and reintroduction efforts, contributing to the conservation of endangered species. These contributions highlight the importance of continued support and collaboration between zoos and research institutions in unlocking nature’s secrets and driving valuable scientific discoveries.

Zoos as Educational Institutions for the Public

Zoos are not just places for entertainment and recreation; they also serve as valuable educational institutions for the public. Through interactive exhibits and educational programs, zoos play a crucial role in promoting awareness and understanding of wildlife conservation. They have the power to engage visitors of all ages and inspire future generations of scientists and conservationists. Let’s explore the various ways in which zoos fulfill their educational mission.

Promoting awareness and understanding of wildlife conservation

One of the primary goals of zoos is to raise awareness about the importance of wildlife conservation. By showcasing a wide variety of animal species, zoos provide visitors with a unique opportunity to observe and learn about different ecosystems and the challenges they face. Through informative signage and guided tours, visitors can gain a deeper understanding of the threats to wildlife and the need for conservation efforts.

Engaging visitors through interactive exhibits and educational programs

Zoos go beyond traditional exhibits by offering interactive experiences that engage visitors on a deeper level. Many zoos have hands-on exhibits where visitors can touch and interact with certain animals under the supervision of trained staff. These interactive experiences not only create memorable moments but also foster a sense of connection and empathy towards animals.

In addition to exhibits, zoos organize educational programs such as workshops, lectures, and demonstrations. These programs provide visitors with the opportunity to learn from experts in the field and gain insights into various aspects of animal behavior, conservation, and research. By actively involving visitors in the learning process, zoos make education an enjoyable and immersive experience.

Inspiring future generations of scientists and conservationists

Zoos have the power to inspire and ignite a passion for wildlife conservation in young minds. By exposing children to the wonders of the natural world, zoos can spark curiosity and encourage them to pursue careers in science and conservation. Many zoos offer educational programs specifically designed for children, such as summer camps and school field trips, where they can learn about animals, their habitats, and the importance of conservation.

Furthermore, zoos often collaborate with schools and universities to provide educational resources and research opportunities. These partnerships allow students to gain hands-on experience in fields such as animal behavior, veterinary science, and wildlife conservation. By nurturing the next generation of scientists and conservationists, zoos contribute to the long-term sustainability of our planet.

In conclusion, zoos serve as invaluable educational institutions for the public. They play a vital role in promoting awareness and understanding of wildlife conservation through interactive exhibits, educational programs, and collaborations with schools and universities. By engaging visitors of all ages, zoos inspire a love for nature and foster a sense of responsibility towards the preservation of our planet’s biodiversity. It is essential to continue supporting and collaborating with zoos to ensure that future generations can unlock nature’s secrets and drive valuable scientific discoveries.

Ethical Considerations and Challenges in Zoo-based Research

Zoos have long been at the center of scientific research, providing valuable insights into the behavior, physiology, and conservation of various animal species. However, this research comes with its own set of ethical considerations and challenges. In this section, we will explore the ethical considerations and challenges that researchers face when conducting zoo-based research.

Balancing the welfare of animals with research objectives

One of the primary ethical considerations in zoo-based research is the need to balance the welfare of animals with the objectives of the research. While scientific research can provide valuable knowledge and contribute to conservation efforts, it is essential to ensure that the well-being of the animals is not compromised.

Researchers must take into account the physical and psychological needs of the animals involved in the study. This includes providing appropriate housing, nutrition, and enrichment to ensure their overall welfare. Additionally, researchers must minimize any potential harm or stress that may be caused during the research process.

Ensuring ethical treatment and responsible research practices

Ethical treatment of animals is of utmost importance in zoo-based research. Researchers must adhere to strict ethical guidelines and regulations to ensure that animals are treated with respect and dignity throughout the research process.

This includes obtaining proper consent from the zoo authorities and ensuring that the research is conducted in a manner that minimizes any potential harm to the animals. Researchers must also ensure that the research methods used are scientifically valid and reliable, and that the data collected is used for the intended purpose.

Furthermore, it is crucial to consider the long-term impact of the research on the animals involved. Researchers should assess whether the benefits of the research outweigh any potential risks or negative consequences for the animals.

Addressing public concerns and controversies surrounding zoos

Zoos have faced criticism and controversies regarding their treatment of animals and the ethics of conducting research in captivity. Public concerns about animal welfare, conservation, and the educational value of zoos have led to increased scrutiny of zoo-based research.

To address these concerns, researchers must be transparent about their research objectives, methods, and findings. They should actively engage with the public and provide clear explanations of the benefits and ethical considerations of their research. This can help build trust and understanding among the public and alleviate any concerns or controversies surrounding zoo-based research.

Additionally, researchers should actively collaborate with animal welfare organizations and conservation groups to ensure that their research aligns with the broader goals of animal welfare and conservation.

Zoo-based research plays a vital role in advancing our understanding of animal behavior, physiology, and conservation. However, it is essential to approach this research with careful consideration of the ethical implications and challenges involved.

By balancing the welfare of animals with research objectives, ensuring ethical treatment and responsible research practices, and addressing public concerns and controversies, researchers can conduct zoo-based research in a manner that is both scientifically valuable and ethically sound.

Ultimately, the continued support and collaboration between zoos and research institutions are crucial for unlocking nature’s secrets and driving valuable scientific discoveries. By navigating the ethical considerations and challenges, zoo-based research can continue to contribute to our knowledge of the natural world and aid in the conservation of endangered species.

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• Published: 29 October 2019

What’s new from the zoo? An analysis of ten years of zoo-themed research output

• Paul E. Rose   ORCID: orcid.org/0000-0002-5375-8267 1 , 2 ,
• James E. Brereton   ORCID: orcid.org/0000-0002-9104-3975 3 ,
• Lewis J. Rowden 4 ,
• Ricardo Lemos de Figueiredo 5 &
• Lisa M. Riley 6  

Palgrave Communications volume  5 , Article number:  128 ( 2019 ) Cite this article

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The modern zoo’s roles command empirical enquiry to determine the effectiveness of zoos locally and globally. Ten years ago, published work identified the need for empirical research on a diverse range of species beyond charismatic zoo megafauna. We review zoo-based research published in the decade since this original recommendation. We collectively evaluate zoo-themed research papers from those working in zoos and those external to zoos but studying zoo-housed animals. By systematically searching Web of Science © for zoo-based research and performing inductive content analysis to code year, journal, study animal’s taxonomic classification, and research aims and outputs we evaluate trends in zoo-themed research, contrasted with trends in species holding. Significantly more birds and fish are kept compared to mammals, reptiles and amphibians, but mammals are consistently the primary research focus. Whilst output generally rises, only for birds is a steady increase in publications apparent. Husbandry evaluation is a major aim/output, but papers on pure biology, cognition and health also feature. Most publications lead to “specific advancement of knowledge” including validation of methodologies. We show that: (1) trends in species holdings are unrelated to trends in publication; (2) zoo-themed research makes meaningful contributions to science; (3) zoo researchers should diversify their aim/output categories and chosen study species to close the persisting research gaps that we have identified. Finally, we discuss our findings in the context of evident species biases within research outputs across the broader fields of zoology, conservation and ecology.

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Introduction.

Zoos and aquariums have the potential to be excellent locations to develop, implement and complete scientific research. Zoo populations enable hypothesis-driven questions to be answered on species/topics that would be challenging in the wild. This is evidenced by, for example, ground-breaking insights into the reproductive biology of the critically endangered Sumatran rhinoceros, Dicerorhinus sumatrensis (Roth et al., 2004 ) or results on the energetic costs of locomotion in bears, Ursidae (Pagano et al., 2018 ). Zoological databases that hold information on species’ biology can enhance the scientific literature on natural history and ecology (Conde et al., 2019 ); information that also informs animal management practices and species conservation strategies both in-situ and ex-situ. As centres for both pure and applied science, the output from zoological collections not only covers a range of disciplines (Loh et al. 2018 ) but is of increasing value to multiple stakeholders working in all parts of the world with all taxonomic groups.

The four aims of the modern zoo—conservation, education, research and recreation (Mason, 2007 , Fernandez et al., 2009 ) provide a framework for scientific investigation. The importance of research to the modern zoo is reflected in the number of pieces of national zoo legislation that require research activities to be conducted (Hosey et al., 2009 ). Conversely, entertainment is perceived as the least important role of the zoo (Reade and Waran, 1996 ), yet visitation must be maintained as zoos can be reliant on entrance fees for income. This income provides a means for zoos to fulfil their roles in conservation and education, hence zoos must remain attractive destinations to visit (Bueddefeld and Van Winkle, 2018 ). Research into the educational role of the zoo has scrutinised the effectiveness of zoos as learning environments (Marino et al., 2010 , Dawson and Jensen, 2011 , Moss and Esson, 2013 ). Despite an increase in zoo visitor studies over the past decade (Jensen, 2010 , Moss and Esson, 2010 ), there is little evidence that zoos promote understanding or pro-conservation behaviour. The importance of robust experimental design and application of “good science” is also evident in literature (Wagoner and Jensen, 2010 , Moss et al., 2017 ) promoting the need for an evidence-based approach.

Such an evidence-based approach extends to animal husbandry, central to which is researching animal behaviour. A majority of zoo scientific studies has previously been shown to be of a behavioural nature (Hosey, 1997 ). The relevance of behavioural science to conservation outcomes was postulated by Sutherland ( 1998 ) who states the importance of conserving behaviour as part of conservation objectives. A potential fifth aim of the zoo, to promote excellence in animal welfare (Fernandez et al., 2009 ) further supports the need to increase the amount of scientific study and application of such study, into zoo animal management. An increasingly ethically-aware public, who focus on the importance of good welfare and are not just concerned with animal cruelty (Whitham and Wielebnowski, 2013 ) emphasises the need for zoos to manage their populations to ensure a high quality of life can be attained and maintained for all individuals.

As scientific research that collects data to answer an hypothesis-driven question is key to ensuring husbandry regimes are most appropriate, zoos have invested in collaboration with academics (Fernandez and Timberlake, 2008 ), in the development of research methodologies (Plowman, 2003 , Plowman, 2008 ) and in the creation of research-focussed committees and working groups (BIAZA, 2018b ) to increase and develop their scientific output and its uptake by zoological collections. By expanding on how empirical research is applied within zoological collections (e.g., to husbandry routines, visitor engagement and interpretation objectives, or population management goals) the reach, impact and outcome of each of the zoo’s aims is strengthened.

With a new focus on collection planning for population sustainability (Traylor-Holzer et al., 2019 ), a paucity of scientific research for many familiar (i.e., commonly-kept, often-seen-in-the-zoo) species has been apparent (Melfi, 2009 ). This paper (Melfi, 2009 ) shows that researchers study a limited number of individuals of high-profile, charismatic species—a trend previously noted in the wider field of “wildlife research” (Bautista and Pantoja, 2005 ). Species less appealing to the public but housed in greater numbers across more zoological collections have been ignored. Likewise, when considering species responses to captivity, mammals are often focal subjects (Clubb and Mason, 2003 ) and ecological data are used to inform our understanding of their responses to captivity (Mason, 2010 , Kroshko et al., 2016 ). However, for other non-mammalian taxa we consider how they cope with the human-created environment of the zoo less often (Carere et al., 2011 ). Species with a long history of captivity, well-known and recognisable to the visiting public can still challenge us regarding their optimal captive care (Hatt et al., 2005 , Rose, 2018 ) and empirical, structured research programmes can help redress the balance between what a species needs to thrive and what is provided for survival in the zoo. Therefore, to move forward with species-specific Best Practice (husbandry) Guidelines (EAZA, 2019 ) less considered taxa, common but “ignored” species or animals perceived as less charismatic, e.g., reptiles, amphibians, fish and invertebrates, (BIAZA, 2018a ) need to be the focus of future research attention. Melfi ( 2009 ) highlights this lack of research into non-mammals as the cause of anecdote or “rules of thumb” methods of providing captive care.

As such, the aim of our paper was to look retrospectively from 2009 to 2018 to see how much more scientific research has been conducted into the areas identified by Melfi ( 2009 ) as lacking a research focus. Specifically, we collected research papers from five different taxonomic groups, to evaluate the range of taxa now included in scientific publications and we investigated if/how uptake and output of evidence, useful for management, has diversified. We used Melfi ( 2009 )’s Table 1 (page 581) and Fig. 2 (page 582) as a guide to what constitutes “forgotten taxa”—focussing on those animals with large populations but limited scientific investigation. We have added invertebrates, amphibians and fish to our analysis that were excluded or not fully included in the original Melfi paper for reasons outlined below. Melfi ( 2009 )’s Fig. 2 shows the relationship between the number of individuals of specific animal species held by British and Irish association (BIAZA) zoos, as well as the number of zoos that hold each represented species, compared to the number of projects conducted on these species, based on records from the BIAZA research database. A bias towards the study of a small number of charismatic mammalian species, for example chimpanzees (Pan troglyodytes) , bonobos (P. paniscus) , orangutans (Pongo sp.) , elephants (Elephas maximus, Loxodonta africana) , is clear from this figure. Melfi notes that more projects between 1998 and 2008 were conducted on the two species of Pan compared to all projects on birds, reptiles, amphibians, fish and invertebrates in this sample of BIAZA institutions—90 against 84 studies. We aim to see if such a bias exists in a sample of wider zoo output in the ten years from this dataset being published.

Papers were collected using the bibliographic database Web of Science©. Key term searches were carried out by including zoo* combined with either behaviour*/behavior* or welfare or nutrition and research for each type of taxa (mammal, bird, reptile, amphibian, fish), for example “zoo* bird behaviour*. Each author was assigned a specific taxon and asked to scrutinise search results in the same manner, inputting data into a standardised spreadsheet. In January 2019, the lead author searched for remaining papers in 2018 across all taxa and terms to complete the dataset. Papers were categorised by year, species (and later class, genus and order), aim and main output. Aim was defined as the reason why the research was conducted (e.g., to determine the effect of a change of husbandry routine, or the influence of enrichment on behaviour, or to benchmark positive indicators of welfare). Output was defined as the key finding of the study and how this helps to underpin evidence-based zoo management.

Papers that covered more than one species of the same taxa (e.g., free-flight aviaries) were categorised as “multiple mixed”. Papers that covered a range of species from different taxa (e.g., visitor studies research or research into common patterns of stereotypic behaviours) were categorised as “multiple taxa review”. Papers that detailed methodological advances or novel approaches to data collection were categorised as “theory”. Papers that focussed on people including where data could add information on best practice animal care (e.g., influences on collection planning based on visitor perception) were categorised as “visitor”. Only peer-reviewed scientific papers in the Web of Science© search were included. Conference papers were not counted. In total, 1063 papers were categorised from 236 publications.

The impact factor of each publication was recorded from the individual journal website or from www.bioxbio.com if the impact factor was not clear on the journal’s homepage.

Rationalising aims and outputs from each article

Using content analysis, two authors (PER and LMR) coded the description of a paper’s aim and outcome into an aim class and an outcome class and outcome gain (see Table 1 for explanation). Papers were checked at the original source if both reviewing authors (during coding) were unsure of the aims and outcomes of the paper from its abstract. Aims were prioritised based on the paper’s own statement of their original aim and not on subsidiary findings. The aim “Husbandry and training” also includes papers that investigated visitor effects because visitors are provided in the zoo whether the animal wants them or not and therefore they directly impact on daily husbandry and management decisions. For each paper, one author stated their interpretation of aim and outcome code and this was judged using a protocol (Table 1 ) by the second author who also ensured the first aim/outcome was prioritised. Triangulation was not necessary as the two authors agreed on 100% of codes. Codes were created using an inductive approach. If a new aim/outcome was coded or new example were added, all previously papers in that aim class, outcome class or output gain were re-coded to reduce bias.

Specialised journals and global species holding

To compare any trend in publication output seen in the main Web of Science © dataset with two specialist zoo journals that are i) an annual publication without an impact factor and ii) have only incomplete listing on this database, an analysis of the output from the International Zoo Yearbook, IZYB, (published annually since 1960 by the Zoological Society of London) and the new open-access Journal of Zoo and Aquarium Research, JZAR, (published by the European Association of Zoos and Aquaria, EAZA) was conducted in the same manner (assessing the number of publications per taxa between 2009 and 2018). From these two journals, 354 papers were collected.

To provide context to research output gathered from searching for numbers of papers on specific taxa, data on species holdings of all zoos globally, published in the International Zoo Yearbook, were analysed alongside of the research-focussed data. These (unpublished) species holdings data were collected as part of an on-going additional research project (by author JEB) with the annual number of each species of mammal, bird, reptile, amphibian and fish kept at each zoo being recorded.

Invertebrates

Papers on zoo-applicable invertebrate research were sampled alongside of the main dataset. As we were keen to follow Melfi ( 2009 )’s categories of research subjects as closely as possible and because of the high number of papers to review between authors, details collected on invertebrate papers were restricted to: the name of the journal and year, the type of aim of the paper and the study subject. Again, only papers found in Web of Science © were recorded and the same categories for searching across the complete database were used: e.g., “zoo* invertebrate OR cephalopod OR arachnid welfare”. Abstracts of papers were read to ensure there was an application to zoo populations- i.e., the paper was not solely focussed on laboratory experimentation. A total of 17 papers were identified from 2011 to 2018 across 12 different publications.

Total sample size

Overall, 1434 zoo-focussed research papers were collected for analysis and evaluation (from the main dataset, from the IZYB and JZAR dataset, and for the separate search for invertebrate-specific research).

Data analysis

Data were analysed in R studio v. 1.0.136 (R Core Team, 2016 ). Where required, data were checked for collinearity using the “car package” (Fox and Weisberg, 2011 ), with values <2 taken as acceptable. Plots of residuals in R for each model were used to assess the distribution of data before further testing.

To compare differences between total counts of mammalian, avian and fish species held, a two-sample t -test was run. To determine any change in the number of species in each class housed by global zoos over the course of the study, a one-way ANOVA was run for species counts against year.

To compare the number of papers published against the taxonomic class of species held plus year of publication, a general liner model was run in R and post-hoc testing to ascertain differences between predictors was run using the “pbkrtest” and “lsmeans” packages for R studio (Halekoh and Højsgaard, 2014 , Lenth, 2016 ).

Fitted models were also run in R, with associated linear regression plots, for each outcome, gain and taxonomic class per year to identify any significant trend in the number of papers published on that theme.

For those papers with a focus on one taxonomic class only ( n  = 863), a multinomial logistic regression was run in R studio using “multinom” function from the package “nnet” (Venables and Ripley, 2002 ). The “AER” (Kleiber and Zeileis, 2008 ) and “afex” (Singmann et al., 2019 ) packages were used to generate P values of the model fit from ANOVA and Wald’s tests. Post-hoc testing was run using the “lsmeans” package (Lenth, 2016 ) using (model, pairwise ~ factor | object, adjust = “tukey”, mode = “prob”) to generate P values for each pair of factors for each outcome across taxonomic class.

A linear regression was run in R with follow-up ANOVA analysis of the fitted model to determine the significance of predictors (taxonomic class, aim, outcome, gain and year of publication) on journal impact factor.

To remove any chances of Type 1 error, the Benjamini and Hochberg ( 1995 ) method of correcting the level of significance was employed when comparing multiple P values.

Global species holdings and the taxonomic focus of research papers

Figure 1 shows that birds and fish are the most speciose taxa housed in zoos globally, and amphibians comprise the fewest number of species housed. Significantly fewer species of mammal are housed compared to birds ( t  = −21.07; df = 11896; P  < 0.001) and fish ( t  = −8.86; df = 9291; P  < 0.001). For each taxonomic class, there was no significant change in the number of species held by zoos globally between 2009 and 2018 (mammals P  = 0.985; birds P  = 0.809; reptiles P  = 0.488; amphibians P  = 0.559; fish = 0.999).

The mean number of species within each taxonomic class (white dot, no line) housed globally in zoological establishments that provided data to the International Zoo Yearbook from 2009 to 2018 compared to the number of publications (red dot, red line), per year, for that taxonomic class. Overall birds are the most speciose taxonomic class housed by zoos globally and show the biggest increase in research output

There is a significant relationship between the number of papers published on each taxonomic class, the year of publication and the mean number of species in that class held ( F 14,35  = 58.59; r 2  = 0.94; P  < 0.001). Across years the increase in the number of papers published for all taxonomic classes combined was not statistically significant (regression slope = 7.41; P  = 0.338), suggesting that the overall number of papers on all topics identified from this literature search remains similar.

Significant differences are noted for the output for mammals against reptiles (higher number of mammalian papers), for fish against mammals (lower number of fish papers) and for amphibians against mammals (lower number of amphibian papers), Table S1 (supplementary information). When evaluating the interaction between species held and taxonomic class (species_holding*taxonomic_class) there is no significant relationship, showing that the average number of each species (in each taxonomic class) held in zoos is not influencing the number of publications on these taxa (intercept = 1.16, P  = 0.976) even though the relationship between the overall number of papers published and taxonomic class of animal is still significant (F 9,40  = 74.65; r 2  = 93%; P  < 0.001). As there is no significant change in the number of species held over this time period, an increase in the holdings of one class is not causing an increase in research output in that specific class.

Trends in the specific categories and aims of zoo-based papers

Analysis reveals that most of the papers have a husbandry and/or welfare focus (see Table S2, supplementary information), be that in the aim ( n  = 301) of the paper or the overall outcome ( n  = 435). The high number of papers coded as a pure biology outcome ( n  = 271) shows that zoos can be centres for the advancement of “blue sky” science, as well as for applied science. This idea is supported by the proportion of papers (75%) that add to our knowledge of the species or topics being investigated. With only 1.7% of papers having no specific gain (i.e., a need for more research to answer the paper’s aim) zoo-based papers are clearly able to impact on knowledge and practice in this area of science.

Is there a relationship between the question being asked and what type of animal is being studied?

The Analysis of Deviance (type II) tests from the model showed that a paper’s aim (likelihood ratio χ 2  = 81.65; df = 36; P  < 0.001), outcome (likelihood ratio χ 2  = 54.23; df = 20; P  < 0.001) and gain (likelihood ratio χ 2  = 30.13; df = 16; P  = 0.017) are all significant predictors of the taxonomic class of the paper. Year was not a significant predictor but may be trending in that direction (likelihood ratio χ 2  = 49.97; df = 36; P  = 0.06). Post-hoc comparison of outcomes for each taxonomic class identified multiple significant predictors (for example Table S3, supplementary information).

Surveying across single-taxonomic class papers only (for the aim, outcome and gain of each paper) shows differences in the proportion of papers on each specific theme by taxa. For fish, 43% of papers had a husbandry aim, 57% of fish papers had a pure biology outcome and 71% of fish papers were identified as having a gain of a specific advancement in knowledge.

Across those papers on reptiles, 45% had a veterinary medicine and animal health aim, 42% had an animal and ecosystem health outcome, and 52% of papers had a gain of a specific advancement in knowledge. For amphibians, 16% of papers had a behavioural aim and 16% had a veterinary medicine and animal health aim, 29% of amphibian papers had a husbandry outcome and 48% paper were identified as providing a gain by specifically advancing knowledge.

An aim of behaviour was identified for 31% of all papers focussing on birds, 39% of bird papers had a husbandry and welfare outcome and 69% of bird papers provided a gain of a specific advancement in knowledge. For papers on mammals, 32% had a husbandry and training aim, 43% had a pure biology outcome, and 70% provided a gain in the specific advancement of knowledge.

For those wishing to advance an evidence-basis for zoo animal husbandry, 23% of all papers provided a gain of how to advance practice (either species-specific or general) with 78% of these being on mammals. Most papers focussed on adding to our knowledge of the study subject(s). Table S4 (supplementary information) further evidences the popularity of specific taxonomic orders as subjects for zoo-themed research by illustrating the types of question asked and output gained on the different taxonomic classes identified in our dataset. Details are provided for the top five orders from mammals, birds and amphibians, for all three orders of reptiles and for all six orders of fish from the ten-year dataset. Bias in the questions being asked at a taxonomic level is evident for each order and may relate to the accessibility of this animal in a zoo or the expertise of the researcher conducting the science.

Predicting future trends

Assessing the main dataset ( n  = 1063) for increases or decreases in the number of publications per theme or on a particular taxonomic group type of animal identifies key areas where zoo research is growing in output. A significant relationship is found for the number of papers published on captive birds over the ten-year period, +3.5 papers/year ( F 1,8  = 26.99; r 2  = 74.3; P  = 0.001), supporting the trend illustrated by Fig. 1 . Papers with an overall methodology aim also increase, +1.01 papers/year, indicating that zoological research is continuing to publish new ways of assessing the animals within collections ( F 1,8  = 30.23; r 2  = 76.5; P  = 0.001). Papers with an aim of veterinary medicine and animal health also increase (+1.01 articles per year) significantly ( F 1,8  = 8.97; r 2  = 47.0%; P  = 0.017). Figure S1 (supplementary information) illustrates these trends over time.

There are also increases on year for outcome with 1.12 extra papers per year published on animal and ecosystem health ( F 1,8  = 9.69; r 2  = 49.1%; P  = 0.014). Output of papers with a visitor studies aim was not significant ( P  = 0.08, +0.2 papers/year). Husbandry and welfare outcome papers may tend towards a significant increase of +1.7 papers/year ( P  = 0.062). This general trend is supported by Fig. S1, which shows a rise in this outcome category over time (although this is not consistent from one year to the next). Finally, there is a significant increase (+5.8 papers/year) in the number of papers published that specifically advance our knowledge of zoo animals ( F 1,8  = 38.18; r 2  = 80.5%; P  < 0.001).

Conservation and population sustainability papers and those focussing on human behaviour change outcomes appear low overall, when compared to those on pure biology and on husbandry (Fig. S1). Such information highlights areas for research to expand into in the future to ensure output continues to be novel and relevant.

Patterns of publication from an annual and a new scientific journal

To compare with output taken from the impact factor-listed publications in the main dataset, Fig. S2, supplementary information, shows the publication trend for the IZYB and for JZAR. Trends in the IZYB data are harder to predict, even though overall the number of mammal-focussed papers is higher than for other classes (47% overall). However, a notable pattern of mammal-focussed publication is evident in each year of JZAR; since its first publication in 2013, 59% of papers are on mammals. All single-class taxonomic categories aside from mammals can be absent from each of these two publications (Fig. S2). Therefore, consideration for the theme of each volume or the breadth of papers included within may be needed to ensure that a wide-range of species are focussed on per edition.

Assessing impact

Differences are apparent in the spread of journal impact factors for where papers on each class of animal and each type of research topic are published (Fig. 2 ). The top five highest impact factor journals include research on multiple taxonomic classes and papers that provide a general advancement in knowledge (with one species-specific focus (elephants) that provides a specific advancement in knowledge). Of the 1063 papers from 2009–2018, two are published in journals with an impact factor of above 10, with the majority (75%) published in journals with an impact factor of below 2.

Boxplots to show the median impact factor of papers for each type of animal or research aim. Top: taxonomic class (A amphibians, All All classes included, B birds, F fish, M mammals, M+ Mammals plus another taxa, R Reptiles, RA+ Reptiles and amphibians plus another taxa). Middle: Aim category (BEH Behaviour, BPR Breeding programmes, HUS husbandry and training, MTH methods, NUT nutrition, PHY physiology, VET veterinary medicine and animal health, VIS visitor studies, WEL welfare). Bottom: Outcome category (AEH animal and ecosystem health, BCH behaviour change human, CSN conservation and sustainability, HUS husbandry and welfare, PUB pure biology, SCI scientific validity). Papers covering all taxa show the largest range in impact and the highest impact overall

Papers with Husbandry and welfare, Human behaviour change, and Conservation and sustainability outcomes are published in the highest impact journals. Papers with a Welfare, Visitor studies, Methods, and Husbandry aim are also found in these higher-impact publications. It is exciting to see that a wide range of topics can be published and disseminated widely across the breadth of the scientific literature- zoo-focussed research is not restricted to “zoo only” journals.

There is a significant relationship between several predictors and publication in a higher impact factors journal ( F 34, 1028  = 2.59; r 2  = 5%; P  < 0.001). Taxonomic class ( P  < 0.001), aim ( P  < 0.001) and outcome ( P  = 0.009) are all significant predictors of publication in a journal with a higher impact factor. Year of publication ( P  = 0.36) or gain (0.994) show no relationship to a journal’s impact factor. Model estimates for individual GLMs show significantly higher impact factor journals contain papers covering both reptiles and amphibians (estimate = 1.32, P  = 0.007) and papers on birds were more likely to be published in lower impact factor journals compared to other taxonomic groups (estimate = −0.57; P  < 0.001).

For the aim of the paper, those on nutrition (estimate = −0.49; P  = 0.012) and veterinary medicine/animal health (estimate = −0.33; P  = 0.006) were published in lower impact journals, whereas those on visitor studies were significantly more likely to be found in higher impact publications (estimate = 0.52; P  = 0.002). When assessing each paper’s outcomes, those relating to human behaviour change were more likely to be published in journals with higher impact factors (estimate = 0.94; P  < 0.001) compared to other outcome categories.

Comparing the interaction between taxonomic class and the paper’s aim ( F 61,1001  = 1.85; r 2  = 5%; P  < 0.001) shows that higher impact journals are successfully chosen for physiology papers that cover all classes (estimate = 2.36; P  = 0.04) and for methods papers published on reptiles and amphibians (estimate = 3.06; P  = 0.05). A significant interaction is present for papers on reptiles and amphibians with conservation/sustainability outcomes (estimate = 4.47; P  = 0.001), model summary F 39,1023  = 3.003; r 2  = 7%; P  < 0.001. No significant relationship is noted for any interaction between the paper’s gain and the taxonomic class used as the subject, and choice of higher impact journals.

What about invertebrates?

For the 17 relevant papers obtained on invertebrates, the highest number ( n  = 11, 65%) focussed on reviewing or providing commentary on, across taxa, bigger questions relating to welfare (including a paper on enrichment practices that covered other taxa as well invertebrates to determine preferences for a specific type of enrichment provided and a paper on how to design judgement bias tasks, both of which have important welfare connotations). Papers on cephalopods and those covering a review of invertebrate taxa as part of a wider question (e.g., enrichment or welfare assessment) made up several of the articles recorded ( n  = 5, 29%, respectively). Invertebrates articles could cover pure science (i.e., personality studies), as well as be used to inform the management of other taxa in the zoo (i.e., investigating food supplements for invertebrates that are then used as foods for other species). The median impact factor was 1.5, similar to output presented for other taxa in Fig. 2 . Papers published in the top-five impact factor journals were two articles that reviewed welfare (published in journals with an impact factor of 16), a cephalopod welfare paper (published in a journal with an impact factor of 5.23) and paper on cephalopod personality (in a journal with an impact factor of 4.13) and a review paper on welfare (in a journal with an impact factor of 3).

Our results show that zoo-themed researchers are increasing their research output year-on-year; Fig. 1 illustrates that, for bird research at least, the overall trend in output is positive. A bias in the study of large charismatic mammals dominates the overall number of papers published, but zoo-themed researchers are investigating a wide array of topics and increasing their output into areas of knowledge gain, as well as practical application (Fig. S1, supplementary information). This mammal bias appears similar to that noted in the wider field of zoology (Bautista and Pantoja, 2005 ) and the need for a more informed approach (such as our call for more scientific investigation for taxon-specific husbandry guides) is echoed by previous research that highlights a lack of scientific rigour within strategies implemented for habitat and wildlife conservation (Reichhardt, 1999 ).

Zoo-themed research output appears to be aligning with wider conservation messages, for example as emphasised by the One Plan Approach (CBSG, 2015 ), as well as with moves to encourage more direct pro-environmental human behaviour change (Smith et al., 2008 , Spooner et al., 2019 ) and wider usage of ecological evidence for the development of species-specific management plans (EAZA, 2019 ). We demonstrate that zoo-themed research output can cross academic boundaries and answer big questions that extend far beyond the animals housed at the zoo themselves. Increases in the number of papers adding to knowledge of species biology shows the wider relevance of zoos to “blue sky” science and an impact across different fields for all taxa investigated (Fig. 2 ). This expanding and considered research output appears to align with developments noted in other areas of biology too- for example the relative success of conservation initiatives in the United States (Schwartz, 2008 ) even though data to underpin these measures can often be lacking.

The focus on specific taxonomic groups compared to others (Table S1) may be a facet of the particular research interest of individual scientists, the commonality of a particular species in the zoo, or the availability of species in zoos close to the workplace of scientists that are publishing in this field. There are clear trends in the choice of taxonomic order when looking over the aims, outcomes and gains from research published on zoo-housed animals (Table S3), indicating that researchers opt for a particular taxonomic order as a study system when designing how to test an experimental hypothesis. A Husbandry and training aim and a Husbandry and welfare outcome predominates in this dataset (Table S2) showing that zoo research is focussing on key areas of management to improve captive care. This illustrates that the majority of these papers are adding to knowledge to strengthen the aims of the modern zoo, and it is encouraging that only 18 papers provided no firm conclusion to their way. Those researching the zoo are clearly able, in the vast majority of cases, to provide an answer to their question.

Our results identify some interesting trends in how zoo animals are used for research. Notably that reptiles feature more in veterinary and health-related papers than other taxonomic classes, yet whilst mammals are the most commonly studied class (Fig. 1 ), they show the least variation in research aim for across all classes (Table S3), with papers asking either behavioural or husbandry and training related questions. Amphibians are the class with the most diverse array of questions asked—covering breeding, husbandry, nutrition, physiology, behaviour, and veterinary medicine and animal health. This suggests that the conservation relevance of amphibians in zoos (Zippel et al., 2011 ) and the urgency by which captive-naïve populations have had to be created suddenly ex situ (Pavajeau et al., 2008 ) has created niches for variation in research questions more quickly than in mammal populations, for example, that have not been exposed to sudden changes in the novelty of species held.

We identify papers that cover each of the four roles of the modern zoo, demonstrating that zoos are prepared to research how well they are meeting their goals and be scrutinised on the outputs from such research. Given calls for good welfare to be a fifth aim of the modern zoo (Fernandez et al., 2009 ), the high number of papers with a full or in-part welfare outcome (41% of all identified papers) is encouraging. Welfare science is moving quickly, with novel approaches validated (Williams et al., 2018 , Richter and Hintze, 2019 , Yon et al., 2019 ) and an increasing use of natural ecology information as a keystone in determining the relevance of husbandry in the zoo (Rose, 2018 ). Therefore, the application of animal-based welfare assessment to ensure individual welfare is good, rather than a completely resource-based approach is a key area of research for zoos to focus upon (Whitham and Wielebnowski, 2013 ). And as 74% of identified papers that had either a specific or general advancement in practice ( n  = 245) were fully or partly focussed on a welfare outcome, zoos are forging ahead to evaluate many aspects of welfare of the animals they house. Our results indicate this is not confined to a single taxon but relevant to all investigated except reptiles where focus is on health and conservation. This may be because so little of the wild biology is known for many reptilian species that, when in captivity, immediate threats to survival (e.g., disease) must be the primary research concern. Whatever the underlying reason, here there is an identifiable opportunity for future zoo research.

Three key gaps in knowledge of zoo animal management were identified by Melfi ( 2009 ). Firstly, that research tended to investigate indicators of poor rather than positive welfare. Change is evident with research assessing animal-based indicators of a good quality of life now being published (Williams et al., 2018 , Yon et al., 2019 ), and methods for positive welfare assessment for zoo invertebrates, as well as an evidence-basis for captive invertebrate care (Bethell, 2015 , Tonkins et al., 2015 ) can also be found. We demonstrate that targeted research, evidenced by the year-on-year increase in bird research output (for example), with popular aims of husbandry and welfare and with an advancing knowledge outcome, means all aspects of welfare are being considered and investigated.

Secondly that housing and husbandry are historically based on anecdote or tradition. A scientific approach to inform husbandry is noticeable in our dataset, with housing style (Rowden and Rose, 2016 ), daily husbandry regimes (Rose et al., 2016 ), nutrition (Gussek et al., 2018 ), enrichment practices (Costa et al., 2018 ), breeding recommendations (Asa et al., 2011 ) and animal health measures (Greenwell and Montrose, 2017 ) being based on evidence gathered to determine optimal care. The asking of numerous questions (Table S4) with an amphibian model shows that zoo researchers are considering key knowledge gaps at different taxonomic levels when constructing an experimental design. Even within a taxonomic group bias persists as certain species (e.g., Pan spp. in the Primate order) command the evidence-based approach. This is not to say zoos specifically ignore other species as a myriad reasons may explain why the husbandry practices of one species are more science-led than another (for example, the number of individuals kept in zoos). And as Pan sp . studies continue to demonstrate, many research projects are required before an holistic approach to husbandry (and welfare generally) can be achieved. Our paper shows that for many species, zoo research is the start of this evidence-gathering journey.

Thirdly, a lack of species-specific biological data may be inhibiting zoo research output. Well-studied animals, such as Pan sp ., will continue to receive research interest because scientists have a reliable bank of background information to utilise. Consequently, equally important research candidates remain understudied due to this lack of baseline information. Use of ecological information on species’ habitat choices can be used to inform housing (Mason, 2015 , Kroshko et al., 2016 , Mellor et al., 2018 ) and suitability of husbandry can be evaluated via individual preference testing (Mehrkam and Dorey, 2015 , Troxell-Smith et al., 2017a , Troxell-Smith et al., 2017b ). Therefore, constructing “in-zoo” questions based on manipulations that can yield species-specific information means that these poorly understood species can be researched and improvements to their husbandry be made on an evidence-based approach.

We demonstrate that zoo-themed research output is slowly filling in these gaps for more and more species, and we have evaluated how this research can have wider impact across scientific publications with a broader readership (Fig. 2 ). From the output in Melfi ( 2009 ), 89% of the sample concerned mammals (60% of which was primate-focussed), with 8% on birds, 1% on reptiles and 1% on other taxa. Whilst the Melfi ( 2009 ) dataset was restricted to output from only one region (British & Irish facilities), the bias for investigating mammalian species is clear. Within our main Web of Science© dataset, 69% of papers focussed solely on mammals (40% on primates)- therefore highlighting a shift change towards the use of other species as research subjects that is unrelated to the number of species kept of a given taxa.

Inter-disciplinary research also identifies the usefulness of zoo information to big data questions, and such an approach helps further reduce the lack of biological information as identified by Melfi ( 2009 ). Information held in the Zoological Information Management System (ZIMS) database, managed by species360 (species360, 2018 ) has added to the bank of biological information held on non-domestic species (Conde et al., 2019 ) to improve our knowledge and understanding of many important areas of species biology, physiology and life history. To develop this research output, zoos should be increasing the number of scientific studies being published within higher impact journals. Our dataset shows that mammals remain considerably better represented in publications than all other taxonomic groups combined. Indeed, two mammalian Orders, Carnivora (154 papers) and Primates (294 papers), are both better represented in research output than all birds, reptiles, amphibians and fish together (204 papers) for papers covering a single taxonomic class.

Publication output centring on a few species within taxonomic groups that are the focus of research attention is documented (Bautista and Pantoja, 2005 ) and similar reasons are postulated to ones that we cover in our evaluation (i.e., flagship for conservation). These authors also note that fish are an underrepresented group in “wildlife research” and again this echoes our own zoo-focussed findings. Given that aquarium-housed fish can be flagships for conservation research, e.g., McGregor Reid et al. ( 2013 ), there is the potential to build on key traits that make a specific taxa suitable for scientific study to increase its use for research. Increases in species-specific output may be based on active researchers investigating questions on the same taxa because these are considered the most appropriate for that question. However, scientists could consider diversifying the taxa used to ask a similar question. For example, the use of highly-cognitive birds instead of primates for cognition research, facilitating the use of non-mammalian species. Use of cephalopods to determine personality differences (Carere et al., 2015 ) can be a realistic alternative to primate studies given the complex cognition of these invertebrates (Mather and Dickel, 2017 ) that involves both short- and long-term learning and engagement in behaviours such as play.

However, we should also be mindful of the importance of knowledge gaps (e.g., the achievement of optimal welfare) for all captive species, regardless of taxonomic class and therefore zoos should actively engage in directed scientific research to answer key applied questions. A lack of background knowledge on such species, hampering effective evaluation of any results generated, may be causing researchers to choose more familiar species as study models. When considering zoo-specific and open access publications (Fig. S2, Supplementary information) there is an overall predominance of mammalian-research noted, even when annual volumes are themed around a particular taxa, such as freshwater fish (McGregor Reid, 2013 ), or area of work, such as reintroduction and translocation practice (Gilbert and Soorae, 2017 ).

The continuing decline in biodiversity is resulting in zoos providing care for species with a limited to non-existent captive history. Science has a role to play in informing practice for these species if species conservation initiatives are to be successful. Zoos and aquariums are unique in their capacity to provide direct conservation action to threatened species across the globe (Michaels et al., 2014 , Biega et al., 2019 ), and it is encouraging to see that many zoo research projects already focus on conservation breeding and the wider role of animals in ecosystem health. Zoo studies currently are used to better inform conservation projects for animals in situ (da Silva et al., 2019 , Lacy, 2019 ) and this trend is likely to continue into the future. The success of in-situ conservation initiatives can be hindered by a lack of evidence (Reichhardt, 1999 , Schwartz, 2008 ) and therefore decisions that influence population management, breeding recommendations and similar measures to conserve biological diversity ex situ must have an evidence basis to them.

The Convention on Biological Diversity (2020) is currently developing a post-2020 global biodiversity framework, which will aim to address the key drivers of extinction (CBD, 2019 ). A key area for future focus is the relatively poor representation of amphibians, both in zoo collection plans, and also in the research output. Zoos appear to be housing relatively few species of amphibians. In relation to biodiversity and conservation, there are over 7900 amphibian species, and roughly 40% of these species are threatened with extinction (IUCN, 2019 ). While some animal collections have produced excellent conservation education strategies centred around amphibians (Pavajeau et al., 2008 ), it is clear there is room for development of collection plans for these species. It may be difficult for visitors to appreciate the diversity of threatened amphibians if few are represented in captivity (Michaels et al., 2014 b).

Because zoological collections have the responsibility of maintaining populations of highly endangered species, prioritising research into areas of population sustainability, educational initiatives and human behaviour change, can help inform the overall conservation plan for species at the brink of extinction. Whilst our results show that current conservation and ecosystem health output appears low, there is evidence that the quantity of research output is growing. This range of publications has value for those engaged in direct conservation action, as well as to educators disseminating information to zoo visitors and beyond.

It is interesting to note that the best represented animals in our dataset also appear to be some of the favourite animals of zoo visitors (Carr 2016 ). Primates, carnivores and elephants are well-represented in the public’s top ten favourite animals (Courchamp et al., 2018 ) and whilst it is beyond the scope of this paper to determine why these animals appear to feature in both public interest and in zoo literature, we do suggest that public interest could act as a driver for research focus on this species (i.e., to better inform practice and scrutinise the extent to which species are presented to visitors). We do not suggest “less primates” in the output from zoos but more focus on other taxa, as well as the continuation of high levels of research on traditional study species. We would encourage researchers to consider their choice of study population carefully and think about other benefits to their research. It might be intriguing to study chimpanzees but is there more added conservation, education and recreational value if the waxy monkey frog (Phyllomedusa sauvagii) was studied instead…?

In conclusion, our results demonstrate that, globally, zoo-themed researchers have an impressive scientific output and are investigating a range of empirical, hypothesis-driven questions that relate to all the modern zoo’s key roles. Between 2009 and 2018, considerable progress has been made regarding the number of zoo-based publications, especially papers focussed on welfare assessment or improvement. Our results show that there remains a mismatch between the number of species within a taxonomic class held in captivity and the representation of this class in the peer-reviewed literature. Whilst it is relevant that some charismatic species are receiving considerable publication interest, further focus on species that are less represented in literature would help the zoological community to develop welfare indicators and evidence-based husbandry more rapidly for a wider range of taxa. The research output of zoological collections is worthwhile, not only for those working within the industry, but also for those working in other capacities with wild animals and in related disciplines (e.g., academia). As such, progress in increasing the number of questions being posed and output of answering such questions, both within and beyond the zoo, has value to people and animals worldwide.

Data availability

The dataset on publications gathered from scientific databases is available at Open Research Exeter: https://ore.exeter.ac.uk/repository/handle/10871/39092 . The dataset generated on species holdings are not publicly available due to this project still be researched but are available from author James E. Brereton upon reasonable request.

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Acknowledgements

We thank A. Loader for her help with compiling data from JZAR and the IZYB. We thank S. Bereton for assistance with the global species holdings dataset. The open access publication charge was covered by the University of Exeter’s Institutional APC Fund.

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Rose, P.E., Brereton, J.E., Rowden, L.J. et al. What’s new from the zoo? An analysis of ten years of zoo-themed research output. Palgrave Commun 5 , 128 (2019). https://doi.org/10.1057/s41599-019-0345-3

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Mutual benefits of research collaborations between zoos and academic institutions

Affiliation.

• 1 Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana.
• PMID: 19360641
• DOI: 10.1002/zoo.20215

Zoos focus on welfare, conservation, education, and research related to animals they keep. Academic institutions emphasize description, experimentation, modeling, and teaching of general and specific animal biology and behavior through work in both laboratory and field. The considerable overlap in concerns and methods has increased interest in collaborative projects, but there is ample room for closer and more extensive interactions. The purpose of this article is to increase awareness of potential research collaborations in three areas: (1) control and analysis of behavior, (2) conservation and propagation of species, and (3) education of students and the general public. In each area, we outline (a) research in zoos, (b) research in academics, and (c) potential collaborative efforts. Zoo Biol 27:470-487, 2008. (c) 2008 Wiley-Liss, Inc.

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Zoos and aquariums shift to a new standard of ‘animal welfare’ that depends on deeper understanding of animals’ lives

Professor of Biology, Psychology, and Environmental Science & Sustainability, and director of the program in Zoo & Conservation Science, Drake University

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Michael J. Renner is a pro bono member of the board of directors and chairperson of the research commitee at Blank Park Zoo ( www.blankparkzoo.net ), an AZA accredited zoo. He is also a pro bono member of the board of directors for the Ape Initiative ( www.apeinitiative.org ), an AZA certified facility.

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In 1980 I visited the zoo in a major U.S. city and found row after row of bare concrete boxes with jailhouse-style bars occupied by animals from around the world. The animals appeared to be in good physical condition, but many were staring into space or pacing restlessly around the edges of their tiny quarters. It was depressing. I’m not naming the zoo, because you could have seen the same thing at most U.S. zoos in that era.

More recently, visitors to many zoos and aquariums see animals in surroundings that resemble their native habitat, behaving in ways that are typical for their species. What has changed?

In the intervening years, the professional zoo and aquarium community has fundamentally altered the way it views the task of caring for the animals in its collections. Instead of focusing on animal care, the industry is now requiring that zoos meet a higher standard – animal welfare. This is a new metric, and it represents a huge change in how zoos and aquariums qualify for accreditation.

I am a scientist who studies animal behavior , both in captivity and in the wild. This recent development in the zoo world is the result of an evolution in the scientific understanding of animals’ lives and welfare . It also reflects zoos’ and aquariums’ increasing focus on conservation .

From trophy case to conservation message

Since the first animal menageries in ancient Egypt , zoos and aquariums have taken a progression of forms.

The British Royal Menagerie, which was housed in the Tower of London from the early 13th century until 1835, served as an animated trophy case. In Europe, exotic animal collections were often displayed in garden settings for the amusement of the gentry, and by the late 18th century, for the general public as well . These places often functioned as stationary circuses, sensationalizing the strangeness of animals from afar.

In Victorian England, zoos were recast as edifying entertainments. This was also true in the U.S., where the first zoo opened to the public in Philadelphia in 1874.

Early zoos weren’t very good at keeping animals alive. In the first half of the 20th century, though, zoos began to focus on animals’ physical health. This ushered in the “bathroom” era in zoo design, with an emphasis on surfaces that could be steam-sterilized , such as ceramic tile.

Over the past 50 years, a landscape immersion model of zoo design has risen to prominence, as institutions have evolved into conservation and education organizations. By displaying animals in settings resembling their natural habitat – and setting the scene for visitors to imagine themselves in that habitat – the hope is to instill in visitors who might never see a lion in its element a passion for its preservation.

Changing standards

Accreditation is a mechanism for maintaining and pioneering best practices. Being accredited by the Association of Zoos and Aquariums is the highest level of professional recognition for North American zoos and aquariums. Fewer than 250 out of approximately 2,800 animal exhibitors licensed by the U.S. Department of Agriculture are AZA accredited.

To earn that accreditation, a zoo or aquarium must demonstrate alignment with its mission, a sound business operation and significant activity in the areas of education, conservation and research. But the centerpiece of accreditation is demonstrating quality of life for animals under human care.

For decades, the focus was on practices that correlate with animal health, like absence of illness, successful reproduction and longevity. The AZA has published objective standards for what it means to provide proper care for a tapir, a tiger or a Japanese spider crab – for example, requirements specifying certain amounts of physical space, environmental temperature ranges and cleaning routines. These extensive and detailed standards were devised by working groups of experts in various species from across the zoo and aquarium community and based on the best available scientific evidence.

A recent revision to accreditation standards in 2018, however, supersedes this model in favor of a new goal – that a zoo or aquarium demonstrate it has achieved animal welfare. Not only must animals be healthy, but they should also display behavior typical of their species. Climbers must climb, diggers must dig and runners must run.

Understanding the lives of animals is central

Over the past 60 years, scientific understanding of animals’ cognitive abilities has exploded. A large body of scientific work has shown that a relatively rich or impoverished environment has effects on both brain and behavior . Such awareness has led the zoo and aquarium community to formally embrace a higher standard of care.

Zoo or aquarium personnel can provide such behavioral opportunities only if they know what is normal for that species in the wild. So optimizing animal welfare requires a knowledge base that is both broad and deep. For example, a zoo must understand what is normal behavior for a pygmy marmoset before it can know what behavioral opportunities to provide.

Many zoos and aquariums house hundreds of animal species. Each species exists because it occupies a unique niche in the ecosystem, so the conditions that produce ideal welfare for one species may not be the same as those for a different species.

Developing welfare standards for the wide diversity of zoo species will take time and quite a bit of research. Although AZA-accredited zoos and aquariums contribute over $200 million per year to research in over 100 countries around the world, the need for conservation research always far outstrips the available funding.

How old is an eastern black rhinoceros before it begins to go on adventures away from its mother? If a flamingo chick has a medical issue that is successfully resolved, how can keepers tell if its development has been affected? How can keepers evaluate whether items introduced into the enclosure of a troop of Japanese macaque monkeys, intended to enrich their environment, are actually serving that purpose? Knowing the answers to these questions, and a multitude of other similar ones, will help the zoo community truly optimize the welfare of animals under their care.

Another major factor behind the AZA’s new standard is its role in species conservation. Captive animals typically outlive their wild counterparts. Zoos and aquariums are the figurative lifeboat for an increasing number of species that are extinct in the wild . Simply keeping an animal alive is now no longer enough. Zoo-based efforts to save endangered species will succeed only if understanding of the animals’ lives is fully integrated with husbandry standards.

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5 ways your zoo uses science every day

Posted on Tuesday, April 18th, 2017

From daily care of the animals at the Zoo to advanced research of husbandry, behavior and diet that is used to set standards for animal welfare, the Zoo’s research and animal care staffs use science in ways big and small.

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Research power of zoos

Alongside conservation and education, one of the core tenets of a modern zoo is research – but what exactly is the contribution to science from eaza zoos this new piece of fascinating research involving chester zoo’s research officer, dr. lindsay eckley, set out to find out just that..

In this multi-institutional collaboration, comprising of researchers from Chester Zoo, Copenhagen Zoo, and Manchester Metropolitan University, the research team reviewed over 3,300 publications from 291 institutions, which included research topics such as zoology, veterinary sciences, and environmental sciences and ecology. While they found that 65% of institutions had contributed to peer-reviewed science, seven institutions, including Chester Zoo, made up 37% of all publications!

The study also identified a general increasing trend in the number of publications by EAZA members, notably with a more than three-fold increase between 2008 and 2018.

“This paper highlights the tremendous value of zoo research to conservation and the significant contribution that European zoos in particular make to doing practical research that is directly applied to solving welfare and conservation problems on the ground.” – Dr. Simon Dowell, Chester Zoo’s Science Director.

By ensuring that research goes through the peer-review process, zoo researchers ensure their work is of high scientific quality. However, while the study focused on peer-reviewed publications, the authors also highlight the many contributions that zoos have to science outside of peer-reviewed publications through things like contributions to magazines, book chapters, and Best Practice Guidelines, through training opportunities, and by opening their facilities and animal collections to external researchers.

“Scientific evidence is vitally important for making decisions to benefit in-situ and ex-situ conservation. However, to be applied and make a difference on a wider scale, evidence needs to be trustworthy and disseminated. This analysis has shown that zoos and aquaria have the ability to publish valid research in a variety of relevant subjects, but there is room for more. I believe that zoos and aquaria are in a unique position to lead on scientific research and they should be supported to share the results.” –  Dr. Lindsay Eckley, Chester Zoo’s Research Officer.

Figure 1. The number of publications in the top 10 research areas from EAZA zoos between 1998 and 2018.

Read the published research here

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5 Ways How Zoos Are Saving Endangered Species

Published by michael anderson on may 11, 2024 may 11, 2024.

Modern zoos have evolved beyond their not so glamorous history and traditional roles of showcasing (sad) animals ; they have become critical sanctuaries and breeding grounds for endangered species.

Through innovative breeding programs, reintroduction initiatives, cutting-edge research, educational outreach, and habitat restoration, zoos have saved >100 endangered species and are continuing to do so, shaping a sustainable future for our planet’s wildlife.

5 Species Saved From Extinction by Zoos

1. california condor.

• With numbers dwindling to just 27, a captive breeding program initiated by the San Diego Wild Animal Park and the Los Angeles Zoo has helped increase their population, now allowing hundreds to soar in the wild​.

2. Golden Lion Tamarin

• Native to Brazil, this tamarin faced habitat loss but has been supported by global zoo breeding programs, contributing to a third of the wild population today.

3. Arabian Oryx

• Once extinct in the wild due to extensive hunting, the Arabian Oryx was successfully reintroduced thanks to breeding programs in zoos, notably the Phoenix Zoo, and now thrives with over 1,000 individuals in the wild​.

4. Przewalski’s Horse

• Known as the last truly wild horse species, Przewalski’s Horse was once extinct in the wild but has been reintroduced through global zoo collaboration, stabilizing its population and reestablishing it in its native habitats.

5. Panamanian Golden Frog

• Declared extinct in the wild since 2007 due to fungal disease, captive breeding efforts by various zoos have ensured its survival, with ongoing conservation projects aimed at eventual reintroduction.

1. Breeding Programs – Nurturing Tomorrow’s Wildlife

Zoos have become bastions of hope for many endangered species, thanks to their meticulously managed breeding programs . These programs are designed to ensure the survival of species that face the threat of extinction in the wild.

As a matter of fact, the conservation efforts of zoos have can be contributed to the saving of more than 100 endangered species .

By creating controlled environments, zoos can facilitate breeding while maintaining genetic diversity, a crucial element for the health and resilience of species populations.

Genetic Diversity Monitoring

Modern zoos employ sophisticated techniques to enhance the success of their breeding programs. Genetic diversity monitoring is one such technique, where genetic information from various individuals within a species is analyzed to avoid inbreeding and ensure a healthy gene pool.

This practice is essential for maintaining the long-term viability of species , as it prevents genetic disorders that can arise from a limited gene pool.

Artificial Insemination

Another advanced technique used in zoos is artificial insemination . This method allows for the reproduction of species without the need for direct mating, which can be particularly useful for animals that are difficult to breed in captivity or are geographically separated.

Artificial insemination not only increases the chances of successful reproduction but also facilitates the exchange of genetic material between different zoos, further enhancing genetic diversity.

Success Stories of Breeding Programs

California condor.

A prime example of the success of zoo breeding programs is the revival of the California Condor.

In the 1980s, the California Condor population had dwindled to just 27 individuals, putting the species on the brink of extinction. Zoos like the San Diego Zoo and the Los Angeles Zoo launched intensive breeding programs that included genetic monitoring and artificial insemination.

These efforts have been immensely successful, leading to a population rebound with over 400 condors now living in the wild and captivity.

Golden Lion Tamarin

Similarly, the breeding program for the Golden Lion Tamarin has been a triumph.

Native to Brazil’s Atlantic Forest, this species faced severe habitat loss and a declining population.

Through a collaborative breeding effort among several zoos worldwide, over 1,500 tamarins have been reintroduced to the wild, with a current population of about 3,200, demonstrating the profound impact of coordinated breeding initiatives.

Panamanian Golden Frog

Zoos also focus on breeding programs for critically endangered amphibians, such as the Panamanian Golden Frog.

Utilizing techniques like hormone therapy to stimulate reproduction, zoos have managed to breed these frogs successfully in captivity.

These programs not only aim to increase population numbers but also serve as a genetic reservoir, safeguarding species against potential future threats.

2. Reintroduction Initiatives – Back to the Wild

Zoos around the world are playing a pivotal role in reintroduction initiatives, striving to return endangered species to their natural habitats.

Process of Preparing Animals for Release

The journey from captivity to the wild is meticulously planned and executed. There are three stages during the reintroduction process:

1. Behavioral Conditioning

It begins with behavioral conditioning , where animals are trained to develop survival skills necessary for their natural habitats. This includes teaching them to forage for food, recognize predators, and develop social behaviors essential for their species.

For instance, predatory birds might be trained in hunting techniques, while herbivores learn to identify and consume native vegetation.

2. Health and Genetic Assessments

Health and genetic assessments are critical components of the preparation process. Animals undergo thorough health checks to ensure they are disease-free and physically fit for the challenges of the wild.

Genetic assessments help in selecting individuals that will maximize genetic diversity in the reintroduced population, thereby enhancing their chances of long-term survival.

3. Habitat Acclimatization

Habitat acclimatization is another crucial step, where animals are gradually exposed to conditions that mimic their natural environments.

This can involve placing them in large, enclosed spaces that simulate their future habitats, allowing them to adjust to environmental conditions such as weather variations and terrain differences.

Success Stories of Reintroductions

There are many great examples to illustrate how zoos are saving endangered species. Let’s take a closer look at two of them:

Arabian Oryx

A landmark example of successful reintroduction is the Arabian Oryx . Once extinct in the wild due to overhunting and habitat loss, the Arabian Oryx has made a remarkable comeback through coordinated efforts by zoos and conservation organizations.

The Phoenix Zoo, in collaboration with other institutions, led a captive breeding program that saw the population grow significantly. In the early 1980s, reintroduction efforts began in Oman, followed by releases in Saudi Arabia and Israel. Today, there are over 1,000 Arabian Oryx roaming free, symbolizing a triumph in conservation.

European Bison

Another notable success story is the reintroduction of the European Bison . Extinct in the wild by the early 20th century, these majestic animals have been reintroduced to forests in Poland, Belarus, and other parts of Europe, thanks to breeding programs initiated by zoos.

The Białowieża Forest, a UNESCO World Heritage site, now hosts a thriving population of European Bison, demonstrating the effectiveness of reintroduction initiatives.

Challenges & Solutions in Reintroduction Efforts

Reintroducing species to the wild is fraught with challenges, but innovative solutions are continually being developed to overcome these hurdles.

• Habitat Degradation : One of the primary challenges is the degradation or loss of natural habitats, addressed by habitat restoration projects to ensure suitable environments for released animals.
• Human-Wildlife Conflict : Animals reintroduced to the wild often come into conflict with human activities, mitigated through community engagement, education, compensation schemes, and wildlife corridors.
• Genetic Bottlenecks : Maintaining genetic diversity is a challenge in small, reintroduced populations, managed by exchanging animals between different zoos and wild populations to reduce inbreeding risks.
• Survival Skills : Ensuring that reintroduced animals have the necessary skills to survive involves intensive pre-release training, post-release monitoring, and techniques like soft release to enhance adaptation.

25 BEST Zoos in California (Ultimate Review 2024)

3. Research and Innovation – Pioneering Wildlife Science

Modern zoos are at the cutting edge of wildlife research, d riving innovations that are crucial for the conservation of endangered species . Through extensive studies on animal behavior, health, and genetics, zoos are not only enhancing our understanding of wildlife but also developing strategies to protect and preserve biodiversity.

Cutting-Edge Animal Research

Animal behavior research.

Zoos conduct comprehensive research on animal behavior to improve conservation strategies. Behavioral studies help zoos understand the natural habits and needs of different species, which is critical for designing effective breeding programs and reintroduction initiatives.

For instance, zoos have used behavior observation to refine enrichment programs that simulate natural environments , promoting physical and mental well-being in captive animals.

Animal Health Research

Health research is another vital area where zoos excel. Veterinary teams at zoos perform routine health checks, develop advanced medical treatments, and conduct disease research.

For example, the San Diego Zoo’s Wildlife Health Center is renowned for its work in developing vaccines for wildlife diseases, such as the vaccine for the devastating avian malaria that affects Hawaiian birds. This type of research is essential for maintaining healthy populations both in captivity and in the wild.

Animal Genetics Research

Genetic research conducted by zoos plays a critical role in conservation. By analyzing the genetic makeup of different species, zoos can monitor genetic diversity, identify potential inbreeding issues, and develop strategies to enhance genetic health.

Techniques such as DNA sequencing and genome mapping are employed to understand genetic variations and identify traits that can aid in the survival of species. This research has been instrumental in managing captive breeding programs to ensure robust and diverse populations.

Collaborations with Universities and Conservation Organizations

Zoos often collaborate with universities and conservation organizations to amplify their research impact. These partnerships enable the sharing of resources, expertise, and data, leading to groundbreaking discoveries and conservation initiatives.

One prominent example is the Global Conservation Consortium for Cheetahs , which includes zoos, universities, and conservation groups working together to study cheetah genetics, health, and behavior. This consortium has led to significant advancements in understanding cheetah reproduction and health, aiding in the development of more effective conservation strategies.

The Zoo and Aquarium All Hazards Partnership (ZAAHP) is another notable collaboration, focusing on disaster preparedness and response for wildlife. This partnership has improved the resilience of zoos and aquariums to natural disasters, ensuring the safety and continuity of critical conservation programs.

Notable Discoveries and Their Impact on Conservation Strategies

1. genetic markers for susceptibility to elephant endotheliotropic herpesvirus.

Zoos have made several notable discoveries that have profoundly impacted conservation strategies. One such discovery is the identification of the genetic markers for susceptibility to Elephant Endotheliotropic Herpesvirus (EEHV) , a deadly virus affecting young elephants.

This breakthrough, made possible through collaborative research involving multiple zoos, has led to the development of targeted treatments and improved management practices, significantly reducing mortality rates among captive elephant populations.

2. Frozen Zoo

Another significant contribution is the development of the frozen zoo concept by the San Diego Zoo Institute for Conservation Research. This initiative involves the cryopreservation of genetic material from endangered species, creating a genetic reservoir that can be used for future breeding and genetic diversity enhancement.

This technology has been pivotal in reviving populations of critically endangered species, such as the Northern White Rhinoceros.

3. Discovery of Behavioral Adaptations in Captive-bred Animals

The discovery of behavioral adaptations in captive-bred animals has also influenced conservation strategies. Research has shown that captive-bred animals can develop unique behaviors that aid their survival in the wild.

For example, studies on captive-bred California Condors revealed that they could learn to avoid power lines, a significant threat to their wild counterparts. This insight has led to targeted training programs that teach condors to navigate around such hazards, enhancing their survival prospects upon reintroduction.

4. Education and Awareness – Inspiring Future Conservationists

Zoos play a crucial role in educating the public and inspiring future conservationists . Through a variety of educational programs and interactive exhibits, zoos raise awareness about the plight of endangered species and the importance of conservation, fostering a conservation mindset among millions of visitors each year.

Zoos’ Educational Programs and Interactive Exhibits that Raise Awareness

Zoos offer a wide array of educational programs designed to engage visitors of all ages and backgrounds. These programs include:

• School Outreach Programs: Many zoos provide curriculum-aligned educational programs for schools, offering students hands-on learning experiences about wildlife and conservation.
• Conservation Camps and Workshops: Zoos organize conservation camps and workshops for children and adults, focusing on various aspects of wildlife conservation through practical activities.
• Interactive Exhibits: Zoos design interactive exhibits that engage visitors with wildlife and conservation through dynamic and immersive experiences.
• Keeper Talks and Animal Demonstrations: Regularly scheduled keeper talks and animal demonstrations provide visitors with insights into animal care, behavior, and conservation challenges.

Fostering a Conservation Mindset Among Visitors

Zoos are uniquely positioned to foster a conservation mindset among their visitors by creating meaningful connections between people and wildlife. By providing opportunities to observe and learn about animals up close, zoos help visitors develop a personal appreciation for wildlife, which is a critical first step in fostering a conservation ethic.

Emotional Connection

Zoos create opportunities for visitors to form emotional connections with animals through close encounters and storytelling. When visitors see and learn about animals, especially endangered species, they are more likely to feel a sense of responsibility and motivation to protect them.

Awareness of Conservation Issues

Through exhibits and educational programs, zoos highlight the threats facing endangered species , such as habitat loss, climate change, and poaching. By raising awareness of these issues, zoos educate visitors on the urgent need for conservation action and the role they can play in supporting these efforts.

Promoting Sustainable Practices

Zoos often incorporate messages about sustainable living and environmental stewardship into their exhibits and programs. By encouraging visitors to adopt sustainable practices, such as reducing plastic use and supporting eco-friendly products, zoos help promote behaviors that contribute to the conservation of wildlife and their habitats.

Impact on Policy and Conservation Efforts

Public engagement facilitated by zoos has a significant impact on conservation policies and efforts at both local and global levels. By mobilizing public support and raising awareness, zoos contribute to the advancement of conservation initiatives and influence policy decisions.

1. Advocacy and Campaigns

Zoos often lead or participate in advocacy campaigns aimed at protecting endangered species and their habitats. These campaigns can include petitions, public awareness events, and social media initiatives, which help generate public support and pressure policymakers to take action on critical conservation issues.

For example, the “Which Fish?” campaign raised awareness about the unsustainable practices of the European fishing industry, which have led to a destruction of the local marine ecosystem, causing many endangered species to die. By promoting responsible fishing practices and fighting for marine exclusion zones, the campaign managed to prevent further damage being done; and thus, saved hundreds of endangered species from extinction.

2. Funding and Donations

Zoos play a vital role in raising funds for conservation projects through donations, membership programs, and special events. Public support generated through these efforts provides essential financial resources for field conservation programs, habitat restoration projects, and research initiatives.

3. Influencing Legislation

By educating the public and raising awareness about conservation issues, zoos help build a constituency of informed citizens who are more likely to support conservation-friendly policies and legislation . This public support can lead to the enactment of laws and regulations that protect endangered species and their habitats.

4. Collaborative Conservation Projects

Zoos often collaborate with government agencies , NGOs, and other conservation organizations to implement conservation projects. Public engagement through zoos helps garner support for these projects, facilitating their successful implementation and increasing their impact on wildlife conservation.

5. Habitat Restoration and Support – Beyond Zoo Walls

Zoos extend their conservation efforts far beyond their gates, playing a critical role in habitat restoration and environmental stewardship. By leading and participating in initiatives that restore and protect natural habitats, zoos help create sustainable environments where endangered species can thrive. According to the Association of Zoos & Aquariums , zoological institutions are generating more than $160 million every year for wildlife conservation, supporting more than 2,650 conservation projects in 130 countries .

Initiatives for Habitat Restoration and Protection Led by Zoos

Reforestation projects.

Zoos frequently participate in reforestation efforts , planting trees and restoring forest ecosystems that have been degraded or destroyed. These projects help to rebuild critical habitats for species that rely on forested areas, enhancing biodiversity and stabilizing ecosystems.

Wetland Restoration

Wetlands are vital ecosystems that support a diverse range of species. Zoos contribute to wetland restoration by removing invasive species, reintroducing native plants, and improving water quality. These efforts help restore the natural functions of wetlands, providing essential habitats for birds, amphibians, and other wildlife.

Coral Reef Restoration

Some zoos and aquariums are involved in coral reef restoration projects , cultivating coral fragments in controlled environments before transplanting them to damaged reefs. This process helps rejuvenate coral ecosystems, which are crucial for marine biodiversity.

Grassland Rehabilitation

Zoos also focus on the restoration of grasslands , which are important habitats for many herbivores and ground-nesting birds. By reseeding native grasses and removing invasive plants, zoos help restore these ecosystems, providing vital habitats for species such as the black-footed ferret and the greater prairie chicken.

Partnership with Local and Global Conservation Projects

Zoos collaborate with a wide range of partners, including local communities, governments, NGOs, and international conservation organizations, to amplify their habitat restoration and protection efforts. These partnerships are essential for the successful implementation and sustainability of conservation projects.

• Local Community Engagement: Zoos work closely with local communities in habitat restoration projects, providing education, resources, and incentives to encourage participation.
• Government and NGO Collaboration: Zoos partner with government agencies and NGOs to enhance conservation efforts through joint policy advocacy, resource sharing, and project implementation.
• International Conservation Networks: Zoos participate in international conservation networks to collaborate on global strategies, share best practices, and protect endangered species and habitats.

Success Story – Restoration of Coral Triangle

The Coral Triangle habitat restoration project, which was led by zoos, has achieved remarkable success, demonstrating the positive impact of such initiatives on endangered species and their ecosystems.

What is the Coral Triangle Initiative?

The Coral Triangle Initiative is a critical effort focused on restoring and protecting coral reef ecosystems within the Coral Triangle, a region encompassing the waters of Indonesia, Malaysia, Papua New Guinea, the Philippines, Solomon Islands, and Timor-Leste. This area is renowned for its extraordinary marine biodiversity, hosting over 600 species of reef-building corals and more than 2,000 species of reef fish, many of which are endangered due to habitat degradation, climate change, and overfishing.

What is done as part of the Coral Triangle Initiative?

Aquariums like the Shedd Aquarium have been deeply involved in the Coral Triangle Initiative by supporting coral cultivation and transplantation efforts. These initiatives include:

• Coral Nurseries : Establishing coral nurseries where fragments of coral are grown under controlled conditions before being transplanted to damaged reef sites. These nurseries are crucial for cultivating healthy corals that can repopulate degraded reefs.
• Genetic Research and Breeding : Conducting genetic research to identify resilient coral strains that can withstand higher temperatures and acidification. Selective breeding programs are implemented to enhance these resilient traits.
• Community Training : Training local communities in coral restoration techniques and sustainable fishing practices to ensure long-term conservation and stewardship of the reefs.

Outcome of the Coral Triangle Initiative

• Restored Coral Cover : Thousands of square meters of degraded reef have been restored, with coral cover increasing by over 40% in some areas.
• Increased Biodiversity : The restored reefs now support a higher diversity of marine life , including endangered species such as the Green Sea Turtle and the Napoleon Wrasse.
• Community Benefits : Local communities have seen improvements in fish stocks and increased income from sustainable fishing practices and eco-tourism, promoting long-term stewardship of coral reef ecosystems.

As we reflect on the critical role of zoos in wildlife conservation, it’s clear that their contributions extend far beyond traditional animal exhibits. By being dynamic conservation hubs, zoos have saved many endangered species already, and will continue to do so in the future.

Whereas the ethics of zoos are a hotly debated topic, their contributions to saving endangered animals is straightforward and clear.

Top 20 Worst Zoos in America in 2024

Should Zoos be Banned? Pros & Cons of Zoos – UPDATED 2024

Your support is vital in continuing the impactful work of zoos in conservation. Here’s how you can make a difference:

• Visit Your Local Zoo : Your admission fees contribute directly to conservation programs and educational initiatives.
• Donate : Financial contributions support research, breeding programs, and habitat restoration projects.
• Volunteer : Offer your time and skills to assist with conservation efforts and educational programs at zoos.
• Advocate : Raise awareness about the importance of zoos in conservation by sharing information and supporting policies that protect wildlife and their habitats.

Yes, zoos help endangered species through breeding programs, habitat restoration, research, reintroduction initiatives, and public education, significantly aiding conservation efforts.

Zoos have contributed to the conservation of over 100 endangered species, with many successfully bred and reintroduced into the wild, like the California Condor and the Arabian Oryx.

Zoos provide comprehensive care through specialized diets, veterinary care, enrichment activities, and habitat simulations, ensuring animals’ physical and mental well-being. Though, there are some zoos that don’t treat their animals well , which is why there is not a small number of people demanding zoos to be banned , or suggesting to visit ethical alternatives to zoos .

Captivity has saved animals from extinction by providing safe breeding environments, protecting them from poaching, disease, and habitat loss, and facilitating reintroduction into the wild.

Some species might face higher extinction risks without zoos, as zoos provide critical support through breeding programs and conservation initiatives that mitigate threats in the wild.

Without zoos, many endangered species would lose vital conservation support, leading to increased extinction risks and a loss of public education and awareness about wildlife conservation.

Michael Anderson

Michael is a dedicated veterinarian and the owner of a thriving animal hospital. With a passion for animal welfare, he sees himself as an ambassador for animals, advocating for their health and well-being. Michael regularly publishes expert articles on a variety of animal health topics, sharing his extensive knowledge and experience with a broader audience. His writings are a valuable resource for pet owners and animal lovers, offering insights into best practices for animal care. Through his work at the hospital and his contributions to the field of veterinary science, Michael is committed to enhancing the lives of animals and promoting compassionate care.

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Isabel escobar-ibarra , daniel mota-rojas , fernando gual-sill , carlos r. sánchez , fidel baschetto , maría alonso-spilsbury.

Although zoos are committed to wildlife conservation and have a long-term positive impact on visitors’ attitudes towards wildlife, the question of whether maintaining wild animals in human care is justified remains as animal welfare concerns grow and human understanding of animal intelligence and capacities broadens. Zoos have always been the subject of debate, with conflicts between those who argue they save endangered species and educate visitors, and animal rights activists who believe that conditions of wild animals are inadequate and that zoos should not exist. In this review, we do not discuss the moral side of the issue, but the scientific one. This manuscript aims to show the scope of literature available on the strengths and weaknesses of modern zoos regarding wild animal welfare. We provide information useful to argue why zoos are important in modern society and factors that influence welfare are examined. Some potentially stressful stimuli may diminish animal welfare in zoo animals, while some of the benefits zoos offer to conservation and science include the opportunity to study and learn about different aspects necessary to improve management practices; the possibility of breeding wild animals in zoos has been a key factor in the recovery of species that have improved their conservation status. Animal welfare is an essential part of wildlife conservation, so efforts should be directed to ensure the best possible quality of life and optimum conditions of all zoo animals in our care.

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Submitted date: 10/02/2020

Accepted date: 10/26/2020

J. Anim. Behav. Biometeorol.

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Human–Animal Interactions in Zoos: What Can Compassionate Conservation, Conservation Welfare and Duty of Care Tell Us about the Ethics of Interacting, and Avoiding Unintended Consequences?

Simple summary.

This article is an examination of human–animal interactions in zoos from an ethical perspective, their benefits to both human and animal participants, and also their potential risks and ethical dilemmas. Contact with animals can be beneficial for all parties involved, and can indeed lead to pro-conservation and respect for nature behaviours being adopted by humans after so-called “profound experiences” of connecting or interacting with animals. Yet, human–animal interactions may also increase certain individuals’ desires for inappropriate wild-animal ‘pet’ ownership, and can convey a false sense of acceptability of exploiting animals for “cheap titillation”. Three ethical frameworks that may be beneficial for ethically run zoos to incorporate when considering human–animal interactions are: Compassionate Conservation, Conservation Welfare and Duty of Care. Human–animal interactions in zoos may be acceptable in many circumstances, and may be beneficial to both animal and human participants; however, they must be closely monitored through welfare tracking tools. Melding Duty of Care and the two Conservation ethical frameworks would be ideal for assessing the ethical acceptability of such interactions.

Human–animal interactions (HAIs) in zoos can be rewarding for both humans and animals, but can also be fraught with ethical and welfare perils. Contact with animals can be beneficial for all parties involved, and can indeed lead to pro-conservation and respect for nature behaviours being adopted by humans after so-called “profound experiences” of connecting or interacting with animals. Yet, human–animal interactions may also increase certain individuals’ desires for inappropriate wild-animal ‘pet’ ownership, and can convey a false sense of acceptability of exploiting animals for “cheap titillation”. Indeed, this has been reflected in a recent research review conducted on animal–visitor interactions in zoos from a number of different countries and global regions. These are unintended consequences that ”modern, ethical zoos” would try to minimise, or avoid completely where possible, though most zoos still offer close-contact experiences with their animals. Three ethical frameworks that may be beneficial for ethically run zoos to incorporate when considering human–animal interactions are: Compassionate Conservation, Conservation Welfare and Duty of Care. These three ethical frameworks are concerned with the welfare state and outcomes for individual animals, not just the population or species. Human–animal interactions in zoos may be acceptable in many circumstances and may be beneficial to both animal and human participants; however, they must be closely monitored through welfare tracking tools. The World Association of Zoos and Aquariums (WAZA) has published guidelines for human–animal interactions that are mandatory for member institutions to adhere to, although whether these guidelines are taken as mandatory or suggestions at individual institutions is unknown. Some suggestions for relevant extensions to the guidelines are suggested herein. Melding Duty of Care and the two Conservation ethical frameworks would be ideal for assessing the ethical acceptability of such interactions as they currently occur, and for considering how they should be modified to occur (or not) into the future in zoological settings.

1. Introduction

Human–animal Interactions (HAIs) are common occurrences in zoological institutions, from husbandry practices to interactions with visitors (both regulated and unregulated) [ 1 , 2 ]. Animal–visitor Interactions (AVIs) are often a large component of zoos’ appeal to visitors, and these experiences are also a large component of zoos’ operations and financial viability [ 1 , 3 , 4 ]. It has been estimated that global zoo attendance is over 700 million visitors annually [ 5 ]. Some of these zoo visitors attend purely for entertainment, and/or for direct interactions with animals (for which they are willing to pay) [ 4 , 6 , 7 ]; however, many visitors to modern zoos report considering zoos and aquaria as centres for education [ 8 , 9 , 10 , 11 ]. AVIs may be classified as “direct contact” (such as holding, feeding, brushing or touching experiences) or “indirect contact” (such as visually viewing, gaze-following and/or mimicking through shared enclosure windows, “scattering” food for the animals from a unique vantage point, auditory communication from traditional enclosure perimeters, or the “solving” of combined human–animal input “puzzle walls” installed in some zoo exhibits for “cognitive enrichment” of the enclosure animals). Globally, zoos vary significantly in their offering of direct and indirect contact animal experiences, but almost all zoos surveyed in a 2019 study promoted one or more types of interaction experiences on their public websites [ 4 ]. Yet, these interactions may be at odds with many of the ethical principles upon which “modern, ethical zoos” have built their new moral foundations, and expound their virtues and “social license” [ 1 , 4 , 12 , 13 , 14 ], such as ensuring positive welfare of their captive animals, promoting "natural behaviours", and being compassionate towards individuals as well as populations in their conservation efforts. This article discusses how three prominent ethical frameworks (which are often explicitly or implicitly utilised by zoos) may be used to examine and justify HAIs in zoos (examining interactions with both visitors and with zookeepers), how new guidelines for AVIs published by the World Association of Zoos and Aquariums (WAZA) [ 15 ] perform under these ethical frameworks, and whether the guidelines work in practice alongside the stated missions of some zoological associations and institutions. The three specific ethical frameworks discussed herein are: Compassionate Conservation, Conservation Welfare, and Duty of Care. These three frameworks are not mutually exclusive, although it is suggested here that a deliberate melding of elements and tenets from all three frameworks could make a robust new framework that would be of relevance to zoological institutions. Furthermore, these three frameworks are concerned with the welfare of individual animals, rather than whole populations or ecosystems as most other Conservation or Environmental ethical frameworks are. Many forms of Environmental ethics and Conservation ethics have been espoused over almost the last 100 years [ 16 ], with the collective aim of saving Earth’s last remaining wild and natural places from being paved over by human expansion/exploitation. These ethical frameworks are mostly characterised by a focus on the overall ecosystem health rather than on individual welfare outcomes [ 16 , 17 ]. These ethics have more recently been criticised for perpetuating the status quo of ecosystem or population health always trumping considerations of individual animals’ welfare [ 16 ] (and a lack of empathy for suffering individuals), for sidestepping problematic issues arising from our increasing knowledge of animal consciousness and sentience (and increasing knowledge of harmful anthropogenic impacts) [ 17 ], and for perpetuating the influential, anthropocentric “land ethic” attitude that species conservation is important, yet often only prioritised after human interests (especially where that land, or the animals on it, are of utility or economic benefit to humans) [ 18 , 19 ].

D’Cruze et al. [ 4 ] list five inter-connected goals that many modern zoos and aquaria share: 1. Conservation; 2. Education; 3. Research; 4. Animal welfare; and 5. Entertainment. While many modern facilities place major emphasis only on the first four goals, and shy away from promoting their facilities as places for human entertainment, as mentioned above, many visitors still report entertainment or leisure as their first reason for attending these places [ 4 , 6 , 7 ]. Many zoos and aquaria exist as private, for-profit enterprises, meaning a certain level of revenue is required to remain operational, and then profit is required to financially contribute to their conservation goals. WAZA report conservation as zoos’ core purpose , but their core activity is animal welfare [ 12 ]. Likewise, the American Association of Zoos and Aquariums (AZA) list their mission as “ helping member institutions and animals in their care thrive, through advancing animal welfare, public engagement, and the conservation of wildlife ” [ 20 ]; and the Australasian Zoo and Aquarium Association (ZAA) list saving (conserving) wildlife by inspiring best practice in conservation and (animal) welfare with support from government and community as their strategic mission for member institutions [ 21 ]. Both of these associations detail supporting member institutions’ financial and operational goals as key goals, as well as supporting and facilitating memorable visitor experiences, but they do not list “entertainment” as a key consideration in their strategic documents [ 20 , 21 ]. In fact, most accredited facilities oppose procuring and displaying animals for entertainment purposes, or training animals for “performances”, as part of their new “ecocentric” ethos [ 1 , 14 ]. It is important to note, too, that member institutions pay monetary fees and dues to continue to be members of these self-regulated associations, but the accreditation processes are independent of institutional membership. Accreditation processes with these associations are a benchmarking tool, for monitoring animal welfare standards and meaningful contributions to conservation within individual institutions [ 22 , 23 ]. Whilst human–animal interactions are not discouraged or banned by these associations, strict guidelines and policies around the acceptability of offering these (especially direct) interactions in accredited facilities are being written into modern documentation [ 13 ]. Here, the ethics and the welfare impacts of two types of HAIs shall be discussed: Animal–visitor Interactions; and lesser scrutinised Keeper–Animal Interactions (KAIs) and Relationships (KARs).

2. Human–Animal Interactions

HAIs have been extensively studied in the agricultural/production animal sector [ 24 , 25 ] and the effects of stockperson attitudes and behaviours on the behaviours and productivity of livestock have been well established, and typified in robust models, such as the Hemsworth–Coleman model [ 25 ] based on the psychological theories of reasoned action and planned behaviour [ 26 , 27 ]. Built upon the Hemsworth–Coleman livestock model, there are also a few models of HAIs in zoos, such as the Hosey model [ 28 , 29 ], and the Chiew–Hemsworth model of animal–visitor interactions (published in [ 30 ]). HAI research in zoos has steadily increased over the last few decades [ 14 ]. The results of many studies report mixed welfare effects of human interactions, from negative effects through to neutral and positive effects [ 4 , 14 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ], and many of the results have been found to be very individual specific. Most studies of zoo HAIs to date have focused on assessing AVIs, and, so far, very few studies have assessed and quantified KAIs or KARs [ 32 ].

3. Animal–Visitor Interactions

There are now quite a few studies that have uncovered negative effects of visitor presence and interactions on captive zoo animal behaviour and welfare, especially when those interactions are in uncontrolled circumstances [ 4 , 34 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 ]. There are also many assumed detrimental (but currently unknown) effects of controlled interactions, such as in provided and promoted animal–visitor “experiences” within zoos, especially with understudied animals such as reptiles (e.g., handled snakes and lizards) [ 4 , 35 , 36 , 38 ]. Often, the current standards of housing conditions for these animals are also inadequate, however, and this is likely to increase or confound detrimental effects of other interactions or welfare-impacting conditions [ 45 , 46 , 47 ]. Although, there are also a number of studies that show that many zoo species are apparently unaffected by visitors and their behaviours, if only viewed from a distance (i.e., no direct physical interactions), and it has been supposed that these animals simply view visitors as a type of expected “environmental variation” [ 32 , 43 , 44 , 48 , 49 , 50 ].

Studies on the positive effects of AVIs are sparse [ 4 ], and are limited to very few species, such as lemurs [ 51 , 52 ], giant tortoises [ 35 , 53 ], and leopard tortoises [ 36 ]; and possible positive effects of visitors for orangutans [ 54 , 55 ] and meerkats [ 49 ]. Despite the dearth of research on positive AVIs, it is suggested here that, as research increases, more positive effects for some individual animals within captive groups (and possibly in some whole groups or populations) will be uncovered. This may further increase as AVIs are undertaken in a more controlled, ethical, and evidence-based manner, prioritising consideration of what the animal wants from the interaction, rather than the human [ 56 ]. When considering individual animal welfare as the ultimate priority for modern, ethical zoos [ 1 , 12 ] (especially those zoos adhering to Compassionate Conservation, Conservation Welfare and/or Duty of Care ethical frameworks), fostering positive AVIs (and positive HAIs in general) is of the utmost importance. There are countless anecdotal stories, passed between zookeeping and animal care staff, that exemplify positive human–animal interactions with animals under their charge. Properly recording and quantifying these relationships, to provide empirical evidence that these relationships are beneficial (or that they are not, in some circumstances) is suggested to be a next step in better understanding captive animals’ wants for, or against, these interactions.

4. Ethical Frameworks

4.1. compassionate conservation.

Compassionate Conservation is an ethical framework that has flourished in the last decade, originally conceived to deal with many “wicked problems” [ 1 ] for individual animal welfare in wildlife management, that traditional Environmental and Conservation ethics could not effectively grapple with [ 16 , 57 ]. This framework has become an explicit ethical alignment within the code of ethics of some zoos, such as Zoos Victoria [ 1 , 58 ], although the framework as used in a pro-zoo manner [ 1 ] differs from the original Compassionate Conservation approach [ 57 ], which was largely concerned with wildlife management, and was generally aligned to anti-captivity principles. While its beginnings were of an in situ wildlife conservation focus, the principles of Compassionate Conservation as applied to ex situ conservation efforts within a captive zoo environment are largely the same [ 1 ]. Compassionate Conservation, in its different iterations, has been described by various proponents as ascribing mostly to a virtue ethic (the virtue of Compassion), a deontological ethic (Animal Rights theories), or to consequentialist ethics (the greatest good for the most number of animals) [ 59 ]. It is obviously a pluralistic approach, focused on the wellbeing of individual wild animals as well as larger populations and ecosystems. The main four tenets of Compassionate Conservation are: 1. First do no harm; 2. Individuals matter; 3. Inclusivity; and 4. Peaceful co-existence (an explanation of these principles is available in [ 59 ]). However, these tenets have also been criticised for a lack of clarity on how the specifics of this ethical framework can be applied to novel or complex dilemmas, such as individual suffering for the benefit of populations or ecosystems [ 59 ].

4.2. Conservation Welfare

A new ethic, Conservation Welfare (predicated mostly upon principles of Singer’s Utilitarianism [ 60 ]), has been proposed as a more legitimate and pragmatic framework for zoos, aquariums and other captive animal conservation organisations to become adherents of [ 59 ]. Conservation Welfare is the recent application of Animal Welfare ethics (and some principles of Conservation and Environmental ethics) to conservation practices for non-captive wild animals [ 59 ]. Like Compassionate Conservation, it differs from most Environmental ethics as it is largely focused on the wellbeing of individual animals, not just whole populations, species or ecosystems. Conservation Welfare, like Animal Rights and Compassionate Conservation, asserts that animals do indeed possess inherent value, meaning they are morally relevant, though the difference in Conservation Welfare is that this inherent value does not preclude the possibility of the imposition of individual suffering or death, if it is necessary and for the “greatest good” (i.e., it can be “traded-off”). Still, this ethic always endeavours to minimise pain and suffering in individual animals. Thus, as applied to in situ and ex situ conservation practices, a Conservation Welfare ethic is more pragmatic than Compassionate Conservation, in that the direct imposition of some suffering on some individuals is deemed acceptable (and this will not violate any tenets) as long as this suffering is necessary and justified . Although, what is deemed necessary, justified suffering is still somewhat ambiguous [ 59 ].

4.3. Duty of Care

The Duty of Care ethical framework (which was initially a humanistic ethical framework for humans caring for humans, then companion animals, and then other domesticated animals) is often an implicitly nurtured approach within zoos, distributed amongst the new generation of animal care managers and husbandry staff, as this ethical framework also promotes a duty to provide positive welfare conditions to captive animals which aligns with modern zoos’ goals. That is, as guardians of captive animals, we have a moral duty to provide all levels of care to those animals [ 61 , 62 ], including the provision of opportunities for animals to have “ a life worth living ” or to be able to thrive in captivity [ 1 , 63 , 64 ]. The duty of care ethic is a reasonable melding of two ethics—a deontological “duty-based” ethic (a moral obligation towards another), and a “virtue-based” care ethic (both active provision of care to others, and internally “caring about” (i.e., consideration for) others) [ 61 , 62 ]. Duty of care as a concept reaches far beyond simply an ethical framework, with “ currency in legal, philosophical, ethical, and general animal protection discourse ” [ 62 ]. As opposed to Conservation and Environmental ethics at large, these three specific ethical frameworks above are all concerned with the welfare of individual animals rather than populations.

5. WAZA Guidelines for AVIs

WAZA have specifically published a set of “ Animal-Visitor Interaction Guidelines ” [ 15 ], based on their 2003 Code of Ethics [ 65 ] and their 2015 Animal Welfare Strategy [ 12 ]. There are six key recommendations for AVI’s listed in the document, with further subsections devoted to recommended procedures to meet these guidelines. The six recommendations are:

Prima facie, these guidelines are sensible and easily interpretable ways for reducing the negative impacts of AVIs on animals. However, individual institutional adherence to these “guidelines” in varying regions may be incomplete, inadequate, or altogether ignored (in favour of financial viability or human experience, for example). Likewise, the auditing of guideline adherence seems to be self-prompted by each individual institution, rather than by a broader regulatory body. Institutional adherence to WAZA and regional association guidelines is largely unknown, or at least reviews are held confidentially. Properly assessing these guidelines would also take an individualistic approach, whereas many zoo facilities often keep “encounter groups” consisting of multiple animals of the same species, and often assess their welfare collectively. Individual welfare assessments are becoming more common globally, especially with the development of specific welfare-monitoring tools (following the Five Domains model), such as WelfareTrak ® (Chicago Zoological Society, Chicago, IL, USA) [ 14 , 66 ]. Other issues include interpretation of specific guidelines. For example, guideline 3 states, “ make no unnecessary demands on animals ”, though, what exactly necessary or unnecessary demands during human interaction encounters are is ambiguous. One of the most important guidelines is number 4—“ provide animals with choice of whether to participate or not ”. Choice and control over their immediate situation are now known to be important for an animal’s overall wellbeing and agency, which can lead to positive welfare states, and these concepts are currently being taught to new generations of zookeepers and animal husbandry professionals as crucial provisions for captive animals wherever possible and pragmatic [ 14 , 67 , 68 ]. It is also suggested that it would be pertinent to add an additional guideline here around safe interaction practices, as follows: “7. Only interactions with non-dangerous animals should be allowed and conducted, and if there is a reasonable chance of harm (even if minimal) to either the human or the animal participants, these interactive experiences should be terminated immediately. ” That is, direct physical contact “experiences” with large predatory animals, such as Tigers, Lions, Bears or Orcas, which could potentially cause serious injury or death to the human participants, should not be offered nor conducted by modern, ethical zoological and aquarium facilities. Currently, many of these offered experiences rely on harmful or abusive training practices, physical restraint, bodily mutilations (such as declawing or teeth removal), and punishments to maintain physical and psychological “control” over these large dangerous animals [ 69 ]. This does not preclude the possibility of beneficial positive HAIs between keepers and these animals, nor in fact between unfamiliar visitors and these animals, but direct contact in these situations is always of the highest risk. It should also be mentioned that most accredited zoological facilities have prohibited abusive and/or bodily mutilation practices in their codes of ethics [ 13 , 15 , 65 ], yet these practices still persist at many eco-tourism or unregulated destinations in many regions [ 69 ].

6. Keeper–Animal Interactions

Currently, AVIs are the focus of much research effort [ 4 , 66 , 70 , 71 ]. However, close examinations of keeper–animal interactions and relationships (KAIs; KARs) are sparse, with a few varying results [ 32 , 55 , 72 , 73 , 74 , 75 ]. Due to the persistence of many “ folklore husbandry ” practices [ 45 ], there is a strong possibility that we are currently ignoring many established negative relationships between zookeepers and animals under their charge [ 32 ]. Although, most modern zoological facilities and (nearly all) animal care professionals endeavour to minimise harmful interventions and to ameliorate possible negative HAIs before they become established negative HARs that would be detrimental to the animal’s overall welfare [ 1 , 75 ]. Furthermore, even though they are often communicated through folklore husbandry, many anecdotal stories and personal experiences (some documented in photographs or short videos) shared broadly over social media can sometimes be beneficial for improving KAIs and KARs in circumstances where objective, empirical evidence is not currently available. Folklore husbandry is a double-edged sword, however, and the established folklore is often very resistant to change even when presented with solid scientific evidence to the contrary [ 45 , 46 ].

To date, specific studies on positive KARs have found the following animal-focused results: increased reproductive success in small cats [ 76 ]; lower faecal glucocorticoid metabolites in clouded leopards [ 77 ], white rhinoceros [ 78 ], and Asiatic and African elephants [ 74 ]; reduced abnormal and stress-related behaviours after positive reinforcement training (PRT) in chimpanzees [ 79 ] and polar bears [ 80 ]; and increased responsiveness to husbandry cues after PRT in black rhinoceros, zebras and Sulawesi macaques [ 81 ]. Similarly, human-focused results found that zookeepers reported stronger, more positive KARs with tortoises that they conducted public-visible training sessions with [ 82 ]; another recent study found that zookeepers’ self-reported job dissatisfaction rose when “Keeper-Elephant Bonds” were weaker [ 74 ]. Apart from Alba et al. [ 82 ], all of these KAI studies have focused on mammalian species. Very little is known about KAIs with other classes of animal. It is strongly suggested that an increase in the empirical investigation of KAIs and KARs is necessary and warranted.

7. Are the Benefits Worth Allowing These Interactions?

As just described above, there are some reported benefits (for both humans and animals) of positive KARs in zoos. There is also marginal evidence to suggest that positive AVIs can be beneficial for the animals involved and documented evidence that these interactions do indeed improve visitor experiences, conservation caring and learning [ 4 , 70 ]. So, is there a good case for allowing and promoting AVIs in zoos? The answer is complicated, but yes. As with all complex dilemmas, the devil is in the details, as it were. Firstly, the guidelines as set out by WAZA, plus the suggested 7th recommendation above, should be closely adhered to, to prevent negative effects of close interactions. However, a new model for clearly identifying when these interactions are being “ asked for ” by captive animals needs to be developed (i.e., being more attentive to what animals actually “ want ”, and aware of how we interpret it [ 56 ]). Interactions that are “asked for” by animals means circumstances where animals have been observed “soliciting” interactions from people, either through glass or other barriers, or by direct contact at shared fence lines (as in the case of the Aldabran Giant Tortoises studied in [ 35 ]). Currently, many zoos have moved towards a highly “hands-off” model of animal keeping, such that most direct contact interactions between humans (both visitors and zookeepers) have been minimised, or totally abolished, and are discouraged as much as possible. Yet, this may be a counter to enhancing the overall welfare of animals in some circumstances, especially in situations where the animals are highly motivated to interact but are denied this rewarding outcome. Sufficient time should be dedicated by animal care managers to allow zookeepers or other staff qualified in animal behaviour to observe daily interaction solicitation or engagement by individual animals under their charge, to identify more opportunities for “ positive affective engagement ” interactions that may currently be overlooked or unnoticed. Furthermore, identifying specific individuals that may benefit from positive KAIs or AVIs should be prioritised by zoos as well. These animals may not always solicit interactions, but other personality factors may be apparent that could predict higher enjoyment of these interactions were they to be offered—factors such as high levels of boldness and curiosity are suggested to be a good starting point for investigation. For human participants, provision of these so-called “ profound experiences ” [ 1 ] in safe, controlled zoo environments can indeed be very beneficial for inciting pro-environmental and pro-conservation behaviour and attitudinal change in visitors, ultimately contributing to the zoos’ conservation goals in meaningful ways [ 3 , 43 , 66 , 83 , 84 ]. “Connecting” with wildlife has been rated as a top priority by zoo visitors, although the type of “connections” that they are seeking can vary significantly [ 71 ].

8. Unintended Consequences

Although AVIs may potentially be rewarding for all parties involved in some circumstances, there are also a number of risks associated with close contact experiences offered within zoos. Obviously, there are a number of health and safety issues for both animal and human participants that are involved in these interactions (especially direct physical contact interactions), some of which have been detailed elsewhere [ 4 , 14 , 69 ]. There is also a growing worry among zoo researchers, managers, educators and behaviour change specialists that providing opportunities to directly interact with animals in zoos may “normalise” the behaviours and promote a false sense of acceptability of engaging in these same behaviours in inappropriate circumstances, such as with wild animals or at unregulated “roadside zoos” and eco-tourism destinations with very poor animal welfare standards [ 4 , 69 , 85 , 86 ]. Interactive experiences that present these animals as “tame” or “cute” may also increase the desire to own these types of animals as exotic pets [ 87 ], and celebrities posing with animals at “roadside zoos” and poorly regulated eco-tourism destinations in social media posts can further normalise this problematic behaviour in unaware members of the public. There is a very real potential that “behavioural spill-over” [ 88 ] could occur after these experiences; thus, approach and interaction behaviours would be attempted by visitors in inappropriate circumstances (such as encounters with animals in the wild), especially because the interaction experienced in the zoo environment is likely to be highly rewarding emotionally and physiologically, leading to an increased motivation to engage in these types of behaviours more often [ 88 ].

Compounding these concerns, the ethical values and beliefs that certain individuals hold about interacting with wildlife may very likely increase the risks of inappropriate or ill-advised behaviours occurring. Historically, zoos were created as displays of imperial majesty—purely for elevating social/cultural status, human awe and entertainment [ 1 , 89 , 90 , 91 ]. Modern zoos are attempting to transform into ethical biodiversity conservation organisations that promote education and positive animal welfare [ 3 , 10 , 11 , 92 , 93 , 94 , 95 ], yet entertainment and leisure are still two commonly reported reasons for attending these destinations by patrons [ 1 , 89 , 90 , 91 ]. Indeed, a zoo visitor survey conducted by the author [ 96 ] found that one of the five extracted ethical alignments of visitors was labelled “ human interaction and entertainment priority ”. Visitors that aligned with this component had high agreement responses on questionnaire items such as “ humans should be allowed to interact with ALL animals in the zoo ”, “ zoo animals are like pets ”, “ zoo animals should be treated like pets ”, and “ I believe that it is acceptable to keep ALL types of animals in zoos ”. Patrons that hold these types of ethical views about interactions with wildlife are likely to be minimally concerned with the animal welfare risks associated with these interactions. They may also be less concerned with evaluating or acknowledging unsatisfactory animal handling and keeping conditions at unregulated, poor-welfare eco-tourism destinations, as their main priority in those moments is their own enjoyment (and they will engage in behaviours that are contrary to their usual moral attitudes) [ 97 ]. To counter this problem, engaging (yet stringent) educational elements must be built into interactive animal experiences offered by zoos, to attempt to change perceptions of these interactions as being harmless enjoyable interactions for all parties involved towards a realistic understanding of how the animals may actually feel about such interactions (and why this matters).

9. What Do the Ethical Frameworks Say?

From a Compassionate Conservation perspective, these types of human–animal interactions would usually be discouraged quite strongly. This is because there are many potential risks of harm to the animals involved (even though minor or non-existent in ideal settings), which would violate the first tenet. The repercussions and undesirable consequences listed above would also likely violate the tenet of peaceful co-existence, as most wild animals would be quite fearful or defensive towards humans approaching them for interactions. Whilst the controlled interactions in zoo environments could be beneficial to fostering pro-environmental attitudes if participants were educated correctly, the inherent risks of direct contact interactions are probably too great to allow. The Conservation Welfare framework would only allow these interactions to occur in very controlled circumstances, but would not completely discourage nor prohibit all of these types of direct interactions. The main principle that would have to be followed, however, is that only those interactions that are “asked” for by the captive animals (not the humans), and could be delivered in an absolutely safe and controlled manner, would be deemed acceptable. Although, uncontrolled HAIs at shared fence lines or through glass viewing windows would likely also be acceptable in circumstances where the animals were initiating or soliciting such interactions. Ergo, if the animal is “asking” for the interaction, and the interaction is deemed safe and minimal or zero risk, then this interaction could be used to increase both the individual animal’s wellbeing and welfare, and conservation caring in humans. Though Conservation Welfare would also be opposed to and concerned about negative “behavioural spill-over” into inappropriate circumstances with wildlife or poor welfare destinations, as this is counted-productive to conservation efforts and to fostering respect for nature. Duty of Care ethics would be mostly concerned with the impacts upon the individual animals within that particular captive environment, so many more HAIs in these circumstances would be deemed acceptable. The main principle followed would be to provide that which is best for the overall welfare for individual animals, and hence allowing and facilitating HAIs and AVIs that are positive and rewarding would be best practice. These interactions would have to be assessed for risks and for safety; however, the framework would only be concerned with the participants as they are in the immediate environment, not what the humans could potentially do in other circumstances or other times outside of the interaction. Therefore, effective communication and education for pro-environmental or conservation caring behavioural change in the human participants would not be considered a priority during these allowed interactions.

10. Conclusions: Promoting Positive Interactions

There are many potential risks inherent in HAIs in all circumstances. However, in specific settings there are also many potential benefits, with the potential to greatly enhance animal welfare conditions and human attitudes towards animal (and natural habitat) conservation and environmental caring. They could potentially be a very powerful tool to increase public awareness, engagement, and support for conservation practices and for achieving the goals of many zoological institutions. However, risks to animal and human participants, as well as the risks of inciting future inappropriate behaviours need to be thoroughly assessed and appropriately mitigated, and all direct HAIs should only be conducted in strictly “very low-risk” scenarios. There is great potential to vastly improve positive affective engagement in animals that are highly motivated to engage in these interactions, providing them with more choice and control over their captive environments [ 64 , 67 , 98 ]. Welfare monitoring tools (such as WelfareTrak ® ) should be utilised during all encounters, and direct behavioural observations from each and every session should be rigorously recorded, to ensure that only animals that are benefitting from interacting are continually used in “encounter programs”. Those animals that display fear, avoidance and/or defensive behaviours before, during, or after encounters should cease being used for these types of close-contact experiences. Behavioural observers must also become much more acutely aware of reptile species’ particular behaviours, as these animals’ full behavioural repertoires are still somewhat unknown [ 38 ]. Likewise, more accurate recognition of unreactive, torpid animals (that may be overwhelmed mentally and physiologically by both acute and chronic stressors) as animals that are not coping with their environments and/or handling must be treated as a priority for relevant behaviourists and animal care staff. Melding Duty of Care and the two Conservation ethical frameworks would be ideal for assessing the ethical acceptability of such interactions as they currently occur, and for considering how they should be modified to occur (or not) into the future in zoological settings.

Acknowledgments

The author wishes to acknowledge the help of Paul Hemsworth in testing and tempering the conceptual, ethical and scientific arguments presented within. The author also wishes to thank Peter Sandøe for honing his argument formulation and philosophical and ethical thinking over the course of his PhD as well as the Animal Welfare Science Students of the University of Melbourne (AWSSUM) graduate student group members for their critiques, comments and support throughout the construction of this paper. This paper represents an ethical chapter of a broader ethical and experimental animal welfare PhD thesis conducted through the Animal Welfare Science Centre, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Australia. https://www.animalwelfare-science.net/ .

The author was supported by an Australian Government Research Training Program (RTP) merit-based PhD Scholarship.

Conflicts of Interest

The authors declare no conflict of interest.

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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How Zoos Support Wildlife Conservation

It’s fair to say that zoos have moved away from the image of just being a place for entertainment. Although recreation is still an important focus for zoos, they now place a lot of value on education, research and conservation.

When it comes to conservation, zoos have the ability to conduct plenty of ex situ conservation work, such as captive breeding programs. But, there are also lots of ways that they help support in situ conservation efforts that take place in the wild.

How are zoos helping conservation in the wild?

Providing financial, equipment, and staff support.

Possibly the most important thing a zoo can do to help in situ conservation projects is to provide financial support. It can be difficult for conservation projects to obtain funding. By receiving either one-off sums or, better yet, zoos committing to giving long term financial aid, many projects are able to continue their crucial conservation work.

Along with monetary support, zoos also provide important equipment, research students, and their own staff. Zoo staff are incredibly knowledgeable in animal husbandry, veterinary care, population management and conducting scientific research. With zoos sharing their knowledge and expertise, in situ conservation project staff and volunteers gain important skills that help aid their efforts. 

These endangered radiated tortoises were rescued from poaching and the pet trade in Madagascar. Photo credit: Turtle Survival Alliance.

Zoos Help the Turtle Survival Alliance Rescue Radiated Tortoises in Madagascar

One example of the crucial assistance zoos have provided is a project conducted by the Turtle Survival Alliance . In collaboration with several North American zoos, Turtle Survival Alliance has been working in Madagascar to help save the endangered radiated tortoise.

Staff from zoos were flown in to provide assistance in animal husbandry and veterinary care. This allowed for thousands of radiated tortoises — originally intended to be traded in the illegal food and pet trades — to be rehabilitated and prepared for future release back into the wild.

Learn more about this project from the Turtle Survival Alliance . 

Combining ex situ and in situ Conservation through Captive Breeding and Reintroduction

Zoos also take part in captive breeding programs. This connects zoos worldwide and allows the movement of animals to different locations to successfully breed endangered species, while ensuring high genetic diversity, and managing worldwide zoo populations. Animals produced as a result of breeding programs may then be used to reintroduce species into the wild.

This is where ex situ (captive breeding) and in situ (reintroduction) conservation efforts combine. This union of ex situ and in situ is part of the IUCN’s One Plan Approach which presents the idea of a worldwide population management system between wild and captive populations.

Zoos collaborated to breed golden lion tamarins and prepare them for reintroduction. Photo credit: Smithsonian National Zoo.

Zoos Collaborate to Breed and Reintroduce Golden Lion Tamarins in Brazil

The golden lion tamarin is a great example of the successful combination of ex situ and in situ conservation. A primate found in South America, the wild population of golden lion tamarins was once down to 200 individuals. In 1972, the Smithsonian National Zoo led a conference to discuss how this species could be saved, and created a captive breeding program. By 1981, 143 zoos were involved!

Thanks to this successful captive breeding program, individuals were reintroduced into the wild in Brazil. Now, the population is up to 2,500! About one-third of the wild population is a result of the released captive-bred tamarins.

Learn more about golden lion tamarin conservation .

How are zoos helping the lemurs of Madagascar?

Educating zoo visitors about lemur conservation.

One Ring-tailed lemur and two Red-fronted brown lemurs at the Smithsonian National Zoo. Photo credit: Alex Reddy.

Lemurs are a popular animal in zoo collections, with zoos around the world housing a number of different species. Zoos are in an optimal position to educate the public about lemurs, the threats they face, and the conservation projects that are working hard to save them. This education helps zoo visitors become aware of lemur conservation and then support it through donations, volunteering, or sharing their knowledge and passion with others.

A 2017 study found that zoo visitors’ knowledge of biodiversity and conservation actions that can be taken to protect it significantly increased during their zoo visit. This increase was even larger in visitors who engaged with educational materials such as signs, interactive panels, and films. Thus, zoos have a brilliant opportunity to increase the public’s awareness about key conservation issues!

Supporting Conservation in Madagascar

In addition to educating visitors, many zoos also help in situ lemur conservation projects in Madagascar. Each of our member zoos supports various lemur conservation work. Many zoos are members of joint associations such as Madagascar Fauna and Flora Group and AEECL . And, some zoos are part of zoological societies that carry out their own in situ work in Madagascar. 

A team from the Bristol Zoo is working to build the Akarafa Field Station in northwest Madagascar. Photo credit: Bristol Zoo.

Bristol Zoo Works to Build a Field Station in Northwest Madagascar

Bristol Zoological Society , one of our members run by the Bristol Zoo in the United Kingdom, works in the Sahamalaza region of Madagascar with species such as the blue-eyed black lemur ( Eulemur flavifrons ). The zoo has been working on conservation projects in Madagascar since 2006. Their most recent project involves the building of a research station in the Sahamalaza region. This field station will provide infrastructure for tourists and researchers in this remote, difficult-to-reach region. 

Learn more about this project and help support it .

Blue-eyed black lemur at the Bristol Zoo. Photo from Bristol Zoo website.

The Collaboration of Zoos and Conservation Efforts

There are many ways in which zoos contribute to in situ conservation efforts: financial support, providing resources, educating the public, and sharing expertise. For lemurs, zoos can have a significant impact on conservation efforts by working with conservation organizations towards the same goal: conserving as much biodiversity as possible and saving species in Madagascar from extinction.

Amber Wyard

About the Author

Amber Wyard  is from North Wales in the UK and is currently studying for a MSc in Zoo Conservation Biology. She is passionate about science communication and sharing important wildlife conservation issues. She is fascinated by Madagascar’s incredibly unique wildlife (especially lemurs!) and hopes to one day travel to Madagascar to see some of these amazing species in the wild!

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