Physical and Physiological Indicators of Welfare in Guinea Pigs (Cavia porcellus) Serving as Ambassador Animals

SIMPLE SUMMARY: Ambassador animals give zoo and aquarium visitors the opportunity to connect with nature, but it is important to assess the welfare of these animals while serving in this role. We conducted a study to determine whether guinea pigs housed in a publicly accessible habitat and serving as ambassador animals demonstrated any differences in welfare indicators compared to periods when they are housed off exhibit. We found that individual differences were the largest drivers of glucocorticoid levels, while sex and on- or off-exhibit housing did not have significant effects on mean levels. There were sex differences in variation of glucocorticoid levels. Moving between habitats did not elicit a significant hormone response except when females were moved off exhibit. Neither the amount of handling the animals received nor closure of the exhibit affected hormone levels. Guinea pig body weights were lower on average when on exhibit but did not otherwise significantly differ. Our results suggest that a monthly rotational schedule of exposure to the public does not negatively impact the physical and physiological indicators of welfare studied. ABSTRACT: 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.