Special encounters that allow contact between animals and guests are common in zoos and aquariums. Visitors to the Saint Louis Zoo may touch guinea pigs serving as ambassador animals. We evaluated two welfare indicators in ambassador guinea pigs by comparing glucocorticoid levels and body weights between periods when guinea pigs lived in a habitat accessible to the public and while off exhibit. Mean glucocorticoid levels did not differ between sexes or between on- and off-exhibit periods. There was significant individual variation, and females demonstrated greater variation than males. While on exhibit, glucocorticoid levels slightly but significantly increased in males and decreased in females. Moving guinea pigs between habitats only elicited a significant glucocorticoid response when females were moved off exhibit. Temporary closures of the exhibit had no effect on glucocorticoid levels in either sex. Analyses of the impact of handling rates on males found no impact on glucocorticoid levels. Guinea pigs’ body weights were lower while on exhibit. We conclude that guinea pigs serving as ambassador animals at the Saint Louis Zoo demonstrate comparable physiological profiles while on and off exhibit and, when used in a rotational schedule, are a suitable species for animal encounters involving contact with the public.

Modern herpetoculture has seen a rise in welfare-related habitat modifications, although ethologically-informed enclosure design and evidence-based husbandry are lacking. The diversity that exists within snakes complicates standardizing snake welfare assessment tools and evaluation techniques. Utilizing behavioral indicators in conjunction with physiological measures, such as fecal glucocorticoid metabolite concentrations, could aid in the validation of evidence-based metrics for evaluating snake welfare. We increased habitat cleaning, to identify behavioral or physiological indicators that might indicate heightened arousal in snakes as a response to the disturbance. While glucocorticoid metabolite concentrations increased significantly during a period of increased disturbance, this increase was not associated with a significant increase in tongue-flicking, a behavior previously associated with arousal in snakes. Locomotion behavior and the proportion of time spent exposed were also not affected by more frequent habitat cleaning. These results demonstrate the need to further investigate the behavioral and physiological responses of snakes to different aspects of animal care at a species and individual level. They also highlight the need to collect baseline behavioral and physiological data for animals, in order to make meaningful comparisons when evaluating changes in animal care.

We used the COVID-19 pandemic closure at the Saint Louis Zoo to examine visitor effects on space use and glucocorticoid levels in banteng, grizzly bears, polar bears, and western lowland gorillas. The study was divided into four six-week phases: closure in spring 2020, reopening in summer 2020, fall 2020, and spring 2021 as a seasonal comparison. Space use data were collected using video, and fecal samples were assayed for glucocorticoids. Generalized linear models were used to examine differences in zone occupancy and glucocorticoids between phases. The banteng spent more time near visitors, and glucocorticoids were only temporarily elevated in two of five animals when visitors returned. The grizzly bears spent more time in their habitat than in the den, and the polar bear spent more time near viewing areas after visitors returned. Glucocorticoids did not differ significantly between the closure and reopening for any bears. The gorillas spent less time close to visitors immediately after reopening but this effect waned by fall; glucocorticoid data were not available. Overall, based on space use and glucocorticoid levels, we suggest visitor effects on the gorillas are neutral, on the grizzly bears are neutral or positive, and are positive on the banteng and polar bear.

Long-term evaluations of whether modern zoological exhibits help to maintain variation in the behavior of zoo animals are lacking despite the hope that animals avoid falling into monotonous patterns of behavior or boredom. This study evaluated changes in behavior and habitat use over multi-year periods in nine individuals of five bear species at two zoological facilities. Behavioral data gathered over months to years were analyzed graphically for trends in the direction of change. The habitat use dynamics were assessed graphically by looking for trends in the entropy values over time. We found that the activity budgets remained diverse and were dynamic over time, more so in younger compared to older bears. Changes in behavior suggesting positive welfare were observed, while changes that may reflect declining welfare seemed more likely to be due to age or seasonality. The observed behavioral changes suggest that the bears did not become bored with their habitats; there was likely one to several hours of daily variation in behavior, and stereotypy was rare. The diversity in the habitat use decreased over time as the animals settled into patterns of use reflecting preferences for certain areas of their habitats.