WHEN CONSERVATION BECOMES A FLEXIBLE LABEL
What actually determines which animals zoos keep—and when does maintaining them become wildlife conservation?

A Response To: “Materialising Reform: How Conservation Encounters Collection Practises in Zoos” — Monika Krause and Katherine Robinson

Modern zoos routinely describe conservation as central to their missions. But what does that word mean when institutions decide which animals to acquire, breed, transfer, display or eventually phase out?
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A study published in the Journal of Cultural Economy examined that question through zoo-association guidance and interviews with ten collection professionals from institutions including the Bronx, Berlin, Chester, London, Schönbrunn and Singapore zoos.
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The researchers found that conservation influences collection planning, but it operates alongside numerous other considerations: visitor appeal, educational potential, available facilities, institutional history, animal availability, staff expertise, acquisition costs and the practical difficulty of transferring or phasing out animals already in a collection.
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Their central conclusion deserves careful consideration. Because conservation can refer to breeding, research, education, fundraising, maintaining an assurance population or supporting projects in the wild, the term can be connected—sometimes very loosely—to an extraordinarily broad range of collection decisions.
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The question, therefore, should not be whether an institution can associate an animal with conservation. It should be:

What specific conservation outcome does keeping this animal produce, and how is that outcome measured?
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WHAT ZOOS KEEP

A global analysis of 3,955 terrestrial vertebrate species held within the international zoo network found that approximately 23% were classified as threatened. Viewed from the opposite direction, zoos collectively held only about 15% of the world’s threatened terrestrial vertebrate species.
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Only two of 59 taxonomic orders contained more threatened species than researchers would have expected if species had been selected at random. Threatened rodents, insectivorous mammals, several groups of birds and salamanders were among those underrepresented.
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Another study compared 165 zoo-held mammal species and 228 zoo-held bird species with their closest relatives not maintained in zoos. The zoo-held species tended to be larger, more geographically widespread, less likely to be endemic and distributed in lower-risk regions. They also tended to be less—not more—threatened with extinction.
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These findings do not demonstrate that conservation is absent from collection planning. They show that extinction risk is not necessarily the deciding factor.
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The species most urgently in need of protection may be difficult to obtain, maintain or breed. They may require specialized diets, environments or expertise. Some may be small, unfamiliar to visitors or unlikely to generate attendance and financial support. The very characteristics that make a species vulnerable can also make it less likely to be represented in a traditional zoo collection.
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MANAGED BREEDING IS NOT ONE UNIFORM OUTCOME

Coordinated breeding programs can provide genuine conservation value. Zoo-associated expertise has contributed to the recovery of species including the California condor, black-footed ferret, Arabian oryx and golden lion tamarin. These achievements should be recognized.
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But familiar success stories do not establish that every managed population serves the same purpose.
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A review of 1,863 publications involving North American conservation translocations identified 279 animal species that had been moved and released for conservation purposes. Captive breeding supplied animals for 162 of those species, but zoos provided released animals for only 40.
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Zoo-bred animals therefore contributed to 14% of all species with published conservation translocations and 25% of the species whose releases involved captive breeding. Only 54 zoos were identified as having supplied animals for release, although zoo participation varied considerably among animal groups and was especially important for amphibians.
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Zoos can also contribute through research, veterinary expertise, funding, monitoring and technical support without providing animals for release. Those roles matter. But they should be described accurately.
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Maintaining a captive population may preserve genetic material, develop husbandry knowledge or provide options for the future. That is not automatically equivalent to restoring a self-sustaining population in the wild.
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WHERE BREEDING, RECOVERY AND FIELD CONSERVATION MEET

A separate analysis examined the involvement of North American zoos in recovery programs under the Endangered Species Act.
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Of 482 listed species with recovery plans, 73 plans—approximately 15%—assigned zoos responsibility for at least one recovery action. Those responsibilities included research, population augmentation, monitoring, assurance populations, education, veterinary work and financial assistance.
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The researchers also found zoo-supported field activities that were not reflected in older federal recovery plans. That finding demonstrates that zoo contributions can extend well beyond their grounds.
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However, only ten species appeared across all three categories examined: a federal recovery plan assigning zoos a role, a zoo-reported conservation project and a population managed through an AZA Species Survival Plan.
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The relationship among captive breeding, zoo-supported fieldwork and official recovery priorities is therefore real—but neither automatic nor universal.
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MAINTAINING POPULATIONS FOR WHOM?

Cooperative population management has become increasingly sophisticated. Studbooks, genetic analysis and breeding and transfer plans can help institutions manage animals collectively rather than as isolated collections.
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A study of more than 400 managed vertebrate populations over nearly 20 years found that most did not experience the demographic and genetic deterioration researchers might expect in small, relatively closed populations. Cooperative management appeared to slow or prevent declines in many of them, although some populations remained unsustainable.
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Yet implementation presents another challenge.
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A later analysis evaluated more than 52,000 AZA breeding and transfer recommendations issued from 2012 through 2019. Recommendations to hold animals or prevent breeding were fulfilled at high rates, generally exceeding 88%. Transfer recommendations were completed approximately 61% to 64% of the time.
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Recommendations to breed designated animals had substantially lower fulfillment rates: approximately 29% for mammals, 21% for birds and 15% for reptiles and amphibians.
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The researchers did not identify one institutional factor responsible for those results and emphasized the complexity of managing animals across numerous facilities. Nevertheless, the findings illustrate an important distinction:

Participation in a managed breeding program does not, by itself, demonstrate that a population is sustainable—or that it is connected to recovery in the wild.
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WHEN VISITOR APPEAL ENTERS THE EQUATION

Visitor appeal is not merely an accusation directed at zoos. It is a measurable part of how many institutions operate.
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A global study involving 458 zoos found that institutions with more animals, greater mammal diversity and larger-bodied species generally attracted more visitors. Higher attendance was then associated with participation in a greater number of in situ conservation projects.
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This supports a legitimate argument: charismatic animals can attract visitors, and institutions with greater attendance may have more resources and opportunities to support field conservation.
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But the study measured associations—not proof that displaying a particular animal caused a successful conservation outcome. Attendance served as a proxy for income, while the number of field projects did not reveal how much money was invested, whether those projects were effective or what measurable benefit they produced for wildlife.
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“Popular animals can help generate support for conservation” is a defensible conclusion.

“Keeping popular animals is inherently conservation” is not.
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WHAT ABOUT EDUCATION?

Education is perhaps the most frequently invoked connection between zoo attendance and conservation.
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A 2025 systematic review and meta-analysis examined 56 studies evaluating zoo visits and zoo-led interventions. Overall, visitors demonstrated positive changes in conservation knowledge, attitudes, intentions and reported behavior.
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But the strength of the evidence varied. Thirty-seven studies measured knowledge, 30 measured attitudes and 14 measured intentions. Only seven measured behavior, and the effect on behavior was smaller than the effects on knowledge or intentions.
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Approximately 95% of the studies measured participants immediately after their zoo experience. Consequently, we still know relatively little about whether those changes endure—or whether they produce meaningful action weeks, months or years later.
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Earlier research also identified a persistent selection problem: people who repeatedly visit zoos may already be more interested in animals and conservation. Without adequately comparing visitors and non-visitors, it can be difficult to determine whether a zoo created an attitude or attracted someone who already held it.
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The fairest conclusion is that carefully designed zoo education can improve knowledge and attitudes and may influence some behavior. The evidence does not establish that merely seeing an animal educates visitors—or that attention, emotional response, stated intention and conservation action are interchangeable outcomes.
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RESEARCH VALUE IS ALSO NOT AUTOMATICALLY CONSERVATION VALUE

Zoos have increased their contribution to peer-reviewed research, particularly in animal care, reproduction, veterinary medicine, behavior and welfare. That work can benefit individual animals and expand scientific knowledge.
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Research priorities, however, remain uneven. Global reviews have found a continuing emphasis on mammals—particularly charismatic carnivores, primates and cetaceans—while reptiles, amphibians, fish, invertebrates and less familiar species receive considerably less attention.
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Research conducted on a captive animal may improve husbandry or reveal valuable biological information. But unless the work addresses a conservation need or produces knowledge applicable to protecting wild populations, it should not automatically be presented as wildlife conservation.
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Animal welfare research, basic biological research and species conservation can all be valuable. They are not identical.
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FROM LABELS TO MEASURABLE OUTCOMES

The evidence does not support the claim that zoos make no contribution to conservation. Some institutions provide important funding, scientific expertise, professional training, field support, assurance populations and animals for carefully planned releases. Certain species would almost certainly have disappeared without those interventions.
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Nor does the evidence support placing every captive population, birth, visitor experience or research project beneath one undifferentiated conservation label.
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Responsible transparency requires institutions to explain:

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• Why is this species being maintained?

• Is the population genetically and demographically sustainable?

• Is breeding connected to an established recovery objective?

• Are animals expected to be released, or is the population maintained entirely in captivity?

• What field program is supported, and what measurable outcomes has it achieved?

• What research question is being answered, and how does it benefit wild populations?

• What educational outcome is being measured beyond attention, enjoyment or immediate intention?

• How much funding reaches conservation work in the species’ natural habitat?

• What happens when animals become genetically overrepresented, socially incompatible or surplus to institutional plans?
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  Those questions do not reject conservation. They protect its meaning.
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  CONSERVATION SHOULD DESCRIBE AN OUTCOME—NOT SIMPLY PROVIDE A JUSTIFICATION

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Krause and Robinson’s research helps explain how conservation can become flexible enough to accommodate decisions also driven by visitor appeal, existing buildings, institutional history and the practical needs of managing captive animals.
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The broader evidence confirms that tension. Zoos possess real conservation capacity, but capacity is not the same as outcome. A managed population is not automatically a recovery program. Education is not automatically behavioral change. Research is not automatically wildlife protection. Attendance is not automatically conservation impact.
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If captivity is justified in conservation’s name, the public deserves more than the label.

It deserves a clear explanation of what is being conserved, how captivity contributes and what measurable result could not otherwise be achieved.
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PRIMARY RESEARCH REVIEWED

Krause, M. and Robinson, K. Materialising Reform: How Conservation Encounters Collection Practises in Zoos.
https://doi.org/10.1080/17530350.2021.1952096

Conde, D.A., et al. Zoos Through the Lens of the IUCN Red List: A Global Metapopulation Approach to Support Conservation Breeding Programs.
https://doi.org/10.1371/journal.pone.0080311

Martin, T.E., et al. Mammal and Bird Species Held in Zoos Are Less Endemic and Less Threatened Than Their Close Relatives Not Held in Zoos.
https://doi.org/10.1111/acv.12069

Brichieri-Colombi, T.A., et al. Limited Contributions of Released Animals From Zoos to North American Conservation Translocations.
https://doi.org/10.1111/cobi.13160

Che-Castaldo, J.P., et al. Evaluating the Contribution of North American Zoos and Aquariums to Endangered Species Recovery.
https://doi.org/10.1038/s41598-018-27806-2

Mooney, A., et al. A System Wide Approach to Managing Zoo Collections for Visitor Attendance and In Situ Conservation.
https://doi.org/10.1038/s41467-020-14303-2

Che-Castaldo, J.P., et al. Expected Demographic and Genetic Declines Not Found in Most Zoo and Aquarium Populations.
https://doi.org/10.1002/fee.2362

Gray, S.M., et al. Influence of Institutional Attributes on Fulfillment of Transfer and Breeding Recommendations in Zoos and Aquariums.
https://doi.org/10.1002/zoo.21724

McNally, X., et al. A Meta-Analysis of the Effect of Visiting Zoos and Aquariums on Visitors’ Conservation Knowledge, Beliefs and Behavior.
https://doi.org/10.1111/cobi.14237

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Related Reading:

Zoo Conservation and Collection Planning
Explore related research examining how conservation priorities, visitor appeal and other factors influence which species zoos choose to keep—and whether conservation claims translate into measurable outcomes.

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KeepingWildlifeWild.org

Evidence • Education • Accountability

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