Assessment of Stress in Individual Zoo Animals: Towards Development of Stress-Tracking Tool
In zoos there is a need for concepts of stress to be translated into assessment tools that are accessible to animal care staff. The measurement of stress requires knowledge of (1) what animals respond to with aversion in captive environments, (2) behavioral signs of acute and chronically aversive situations, and (3) long-term biologic consequences of these responses. Measurement of glucocorticoids in feces, urine and saliva is the primary means of studying stress responses in zoo animals, but these measures need to be combined with other behavioral and biologic assessments in order to determine whether stress is a welfare problem or not. In addition, standardized tracking of environmental events that affect animals is essential for monitoring causes of stress. This paper discusses the key elements necessary for developing a zoo animal stress-tracking tool based on studies that pair individual variation in glucocorticoid output with other types of measurements. Results from diverse taxa will be discussed, including black (Diceros bicornis) and white rhinoceros (Ceratotherium simum), polar bear (Uris maritimus), clouded leopard (Neofelis nebulosa), Hawaiian honeycreepers (Himatione sanguinea and Hemignathus virens), okapi (Okapi johnstoni), false killer whale (Pseudorca crassidens), giant panda (Ailuropoda melanoleuca), kori bustard (Ardeotis kori), and orangutan (Pongo pygmaeus).