Studying zoo animals: Why it’s worth the effort

Zoos are a contentious issue for some, but for me, they are a necessary part of modern conservation because of their intrinsic value to learning more about the ecology, biology, and behaviour of animals. However, I feel that zoos must be able to justify the species they house, and explain why these species need human management. From both an academic and applied point of view, the living collections that zoos manage should be selected, not for social or historical reasons, but because they are important biologically, and provide an opportunity to conduct valuable scientific research.

There is much that we do not know about the species that need our help, and zoos in the 21st century are being asked more and more frequently to provide homes for threatened, yet poorly understood, species that, in some cases, may not have been placed in a captive setting before. Similar or related species already housed in zoos can help build our knowledge of what is required by these rarer cousins. Likewise, as wild populations of these seemingly common species dwindle, it is important that we continue to tweak and adapt zoo husbandry regimes to ensure that all such species have a secure and viable future.

Common as muck, right? Not quite. Giraffe (Giraffa camelopardalis) populations have crashed across Africa and this much-loved and very familiar zoo staple is now in real danger. As such, research into best husbandry practices of zoo-housed giraffe is vital to underpin their management to conserve the wider population of this species well into the future.

The modern zoo should no longer be a living stamp collection of weird and wonderful wildlife for humans to gaze upon in awe. Zoo collections must contribute, either directly or indirectly, to conservation work, visitor education, and the attainment of scientific understanding. Species that do not thrive in captivity reduce the value of the animal collection and the raison d’être of zoos overall. I am a firm believer that not every species has a place in the zoo, and collection planning must take into account the relevance of a species actually being in captivity in the first instance.

Zoo-housed species that do well can be used to tell the story of specimens that are much rarer and of real conservation concern, but which are much more difficult to look after in captivity–species that need very specialist care, either in field-based conservation centres or away from humans completely. This “storybook approach” can be very species-specific, for example, the plight of the rare and fragile James’ flamingo (Phoenicoparrus jamesi) can be explained using the sympatric Chilean flamingo (Phoenicopterus chilensis); conservation work to secure the precarious future of the Javan (Rhinoceros sondaicus)  and Sumatran (Dicerorhinus sumatrensis) rhinoceroses can be promoted to visitors by displaying the equally threatened, but easier to care for, Indian rhino (Rhinoceros unicornis); the Madagascar pochard (Aythya innotata), the world’s rarest duck and possibly even the rarest bird, housed in situ in Madagascar and bred for reintroduction, can be championed by all manner of similar wildfowl that abound in captivity.

This storybook approach can also be much more general. The world’s shark populations have taken a nose-dive in recent years and not many aquaria have the space, facilities, or budgets to house large and threatened species, such as the great white shark (Carcharadon carcharias). However, sharks, in general, are aquarium staples and captivate the imagination of the public. Smaller and easier-to-house species can be excellent ambassadors for those other sharks less suited to life in a tank. The current global amphibian decline ranks second—preceded by coral reefs and followed by large Asian mammals—on the International Union for Conservation of Nature’s (IUCN’s) priority list of organisms threatened with imminent doom. Zoo involvement with field-based amphibian conservation initiatives is much more accessible to visitors if commonly-kept (zoo) species are displayed in an engaging and relevant manner.

In the UK, at least, zoos have a legal requirement to facilitate and undertake research within their animal collections. As part of the Zoo Licencing Act, which incorporates the EU Zoos Directive from 1999, a specific document termed the Secretary of State’s Standards for Modern Zoo Practice describes the need for a research programme to be implemented into the running of the zoological collection. The governing body of UK zoos, BIAZA (The British & Irish Association of Zoos and Aquariums), as well as other regional associations, such as the Europe-wide institution EAZA (the European Association of Zoos and Aquaria), have research committees that help support, evaluate, and critique zoo-based research programmes, to ensure that they generate data that are useful to those working with the animals directly, as well as to those managing the larger population of individuals of a species. Ultimately, these data will have a beneficial impact on captive individuals, ensuring that they are managed in the most biologically appropriate way possible.

We know that the wild does not confer the limitless freedom that it may seem to, and those wild animals are constrained by a variety of stresses and environmental pressures (for example, between- and within-species competition, unpredictable resource access, predation threat, and territorial limits). We also know that we need to replicate these wild interactions within modern zoo enclosures to ensure that species remain healthy and behaviorally normal. However, it is not always possible to reconstruct all elements of the natural habitats of all species. This is where research into individual species’ needs can help zoos to determine what types of animals should be maintained on their collection plan.

Research suggests that not all species should be managed in captivity and that some species are better preserved out in the wild with minimal human influence over what they do. Species that do not do well outside of their range states, but still require a more intense level of management, can be maintained by zoological collections in the countries where the species occur naturally, thereby helping to bolster dwindling free-living populations. Conservation work will be more successful if species’ management decisions are based on evidence that keeps populations healthy and viable.

The number of flamingoes in a flock will affect the chances of successful breeding. Past research has provided zoos with information on the minimum number of birds for i) overall good welfare and ii) stimulation of nesting behaviours.

Seminal work on carnivores, for instance, has shown that aspects of their behavioural ecology (notably territory or home range size) can predict whether or not the animals will display stereotypic, or abnormal, behaviour patterns in zoos. Some species of cetaceans (whales and dolphins) may experience shortened lifespans in captivity because we cannot recreate all the important facets of their natural habitat—for example, the complexity and size of the marine environment—and, hence, we should use other species that are more easily and healthily managed in zoos, to tell their story for them.
Research tells us that some species do especially well in captivity. There is a reason why meerkats (Suricata suricatta) are so popular, for example. We can use measurable indicators of positive welfare, such as the performance of appropriate behaviour patterns or temporal physiological changes, to determine the suitability of a managed environment for a particular species. Research into wild ecology allows the formation of best practice guidelines, which are shared between zoos to ensure species are managed to the highest standard possible. The output of research on wild populations and that conducted in captivity (to evaluate which forms of housing and husbandry work best) are brought together into a management regime known as “evidence-based husbandry”, which provides the foundation for how an individual species is managed in captivity, regardless of what zoo is keeping it.

Fussy eater? It can be difficult to provide the correct diets for proboscis monkeys (Nasalis larvatus) outside of their native South-East Asia. Results from dietary studies have shown that this species is best managed by collections that are able to provide these highly-specialised primates with the types of foliage most similar to what they would forage on in the wild.

For example, information on preferred climatic conditions, optimum dietary formation and nutrient requirements, individual space usage and environmental complexity, social grouping and population structure, and when and how often breeding occurs, enable positive welfare to be maintained across the course of each species’ life stages within a captive setting. The use of noninvasive physiological measurements (i.e., metabolites of reproductive hormones taken from faecal and urine samples) is now used with excellent results to assist in the breeding programmes of numerous highly endangered species, including Asian elephants (Elephas maximus) and black rhino (Diceros bicornis). Likewise, measurement of glucocorticoids enables evaluation of an individual’s stress response, which can provide information to help support changes to enclosure layout, visitor flow, housing, and husbandry, in order to maintain an overall positive welfare state. It should be remembered, however, that stress can be beneficial and as increases in adrenal glucocorticoids can occur with excitement, zoos need to maintain a dynamic environment that provides physical, physiological and psychological stimuli. Scientific explorations of environmental enrichment methods can help create such variety.
Ultimately, contented animals, with naturalistic behaviour patterns and biological rhythms are more likely to produce healthy and viable youngsters—a necessary outcome for conservation work. The IUCN is working on a new way of managing threatened species that breaks down old boundaries and simultaneously considers both wild (in situ) populations and zoo-based (ex situ) populations in the development of a single metapopulation management strategy; this is termed the One Plan Approach (OPA). The ultimate aim of the OPA is to integrate more closely the work of those in the field and those working with the same species in the zoo, to collect further evidence on the optimum methods of management and conservation planning, as well as to direct and focus research and knowledge where they are most needed. In an age of climate change and continual anthropogenic pressures, a species’  viability is likely to remain highest when all aspects of its population (captive and free-living) are managed as a whole.

Just a brown duck? Knowledge of the requirements of similar pochard species that have been maintained in captivity for far longer has helped in the development of husbandry protocols for one of the world’s rarest birds, the Madagascar pochard (Aythya innotata)—a species on the brink of extinction that is the focus of multi-zoo, multi-conservation organisation protection work.

Population management is integral to the future security of all species housed in zoos, regardless of how threatened they are. Research using zoo records is particularly important in assessing trends in population growth or determining (and hopefully) halting any population declines. The Zoological Information Management System (ZIMS) contains information on individuals contained in zoo populations around the world, facilitating largescale research projects on robust and statistically sound data sets. This allows researchers to conduct meta-analyses on topics such as longevity, time to maturity, and lifetime reproductive success, producing results that can be shared with other institutions, in order to facilitate the development of stable captive breeding groups.

European zoos have also been collaborating to further increase access to the output from research projects; these partnerships have resulted in the launch of a new, open-access peer-reviewed publication, the Journal of Zoo & Aquarium Research ( It is hoped that by encouraging zoo professionals to submit short case studies or husbandry reports to a free-to-read, fast turnaround scientific journal the dissemination of research output will reach a wider audience and generate further interest in the important research work conducted by modern, evidence-based zoological collections.

The red panda (Ailurus fulgens) is one species for whom a successful OPA has been applied, and a population viability analysis of both wild and captive animals has allowed for the production of a sturdier and more stable and future conservation strategy for this species.

The thorny ethical issue of keeping wild species in captivity may never be fully resolved, but I firmly believe that science-based zoological collections are an essential part of informed conservation practice. “The wilderness”, as many perceive it, may no longer fully exist; complete and boundless freedom is probably never experienced by even the most “wild” of wildlife. However, we should always remember that the species zoos house, have evolved to fit into a specific part of a wider habitat, and, though they may live in captivity, are not domesticated. Therefore, a species should not be made to fit the husbandry provided for it; rather, the husbandry must be tailored to fit each species’ evolutionary and behavioural needs.

Only by using captive collections to conduct research programmes that further advance the science of zoo biology can we uphold the value of a zoo’s animal collection. Some zoos may get bad press for the ways in which their animals are housed, but the vast majority of professionally accredited collections work together to advance zoo husbandry techniques, promote conservation breeding, and conduct worthwhile research on their charges. Zookeepers, curators, and directors are some of the hardest working individuals that I know, and who regularly volunteer their time for “extra-curricular” responsibilities, with the sole aim of improving a lot of the animals in the collection. Zoo science is ultimately good science, and long may it continue.

Further reading:
BIAZA. 2015. BIAZA Research Committee. http:// British & Irish Association of Zoos & Aquariums.
CBSG. 2015. The one plan approach to conservation IUCN SSC Conservation Breeding Specialist Group.
Hosey G, Melfi V, Pankhurst S. 2009. Zoo animals: behaviour, management and welfare. Oxford, UK: Oxford University Press.
Mason G, Burn CC, Dallaire JA, Kroshko J, McDonald Kinkaid H, Jeschke JM. 2013. Plastic animals in cages: behavioural flexibility and responses to captivity. Animal Behaviour 85 (5): 1113- 1126.
Mason GJ. 2010. Species differences in responses to captivity: stress, welfare and the comparative method. Trends in Ecology & Evolution 25 (12): 713- 721.
Rees PA. 2011. An introduction to zoo biology and management. Oxford, UK: John Wiley & Sons. Paul Rose is a PhD student at the Centre for Research in Animal Behaviour, University of Exeter, UK, p.rose@

Photographs: Kartik Shanker, Paul Rose, WWT, Lewis Rowden

This article is from issue


2016 Mar