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Zoo ResearchStudies of Clouded Leopard Behavior Correlating with Stress Hormone Production

Investigator: Dr. Nadja Wielebnowski of the Brookfield Zoo and Dr. Janine Brown of the National Zoological Park's Conservation and Research Center (CRC)

In the last few years, clouded leopards in zoos have been studied in an attempt to help zoologists better manage them by mitigating behavioral problems and enhancing reproduction. The following is a summary of this research.
Since 1998, Dr. Nadja Wielebnowski of the Brookfield Zoo and Dr. Janine Brown of the National Zoological Park's Conservation and Research Center (CRC) have been studying the link between clouded leopard behavior and their production of stress hormones (i.e. glucocorticoids: cortisol and corticosterone) in order to identify factors that lead to problems such as fur-plucking, tail-biting, and excessive pacing and hiding that are often demonstrated by clouded leopards in zoos. Many of these aberrant behaviors are thought to be the result of high levels of stress faced by clouded leopards living in captivity. Finding ways to alleviate this stress is a top priority for zoos housing clouded leopards as well as the Clouded Leopard Species Survival Plan management team.

Their study consisted of monitoring 74 clouded leopards in North American zoos (65% of the population) to gather data on their hormone production. In order to evaluate the level of hormones produced by the cats, the keepers collected fecal samples every other day for six weeks and sent them to the researchers who analyzed them for the hormones in question.

At the same time, the keepers made behavioral assessments evaluating the cats' temperaments, indicating if the cats appeared "stressed" or "calm" and if they exhibited any abnormal behavior.

The results indicated that clouded leopards evaluated by keepers as being "stressed" did produce higher levels of stress hormones than those evaluated as being "calm." Additionally, stress hormone levels were found to be higher in cats exhibiting behaviors such as self-mutilation and excessive hiding. Furthermore, when the researchers analyzed a variety of husbandry factors, such as exhibit height, their ability to see other large cats (i.e. potential predators), and the amount of keeper time spent around the animals, they were found to be linked to the levels of stress hormones produced. For example, high concentrations of stress hormones were measured when potential predators were visible and when cats were on public display. Lower levels of stress hormones were measured when cats had enclosures with high climbing space and also when keepers were able to spend more time with them.

These results indicate that zoo staff may be able to control some of the factors that lead to stress in clouded leopards to more effectively manage this species. In order to identify the best ways to improve clouded leopard management, the researchers are now undertaking a new study to vary several of the husbandry factors that are known to be associated with stress hormone levels. They will be looking at how providing cats with additional hiding and climbing opportunities affects the production of stress hormones in the hopes of being able to make specific management recommendations for improving the behavior and breeding success of clouded leopards in zoos.

The following references provide more information on these studies:

Wielebnowski, N., Busso, J.M., Brown, J.L. 1999.
Adrenal activity in relation to subjective temperament assessment in clouded leopards (Neofelis nebulosa). In: Felid Taxon Advisory Group Action Plan. Annual report. Eds. D.E. Wildt, J.D. Mellen, J. Brown. American Zoo and Aquarium Association, Disney's Animal Kingdom Publ., Lake Buena Vista, FL: p. 74-75.

Wielebnowski, N., Fletchall, N., Carlstead, K., Busso, J.M., Brown, J.L 2002.
Non-invasive assessment of adrenal activity associated of adrenal activity associated with husbandry and behavioral factors in the North American clouded leopard population. Zoo Biol. 21 (In Press).