Fecal glucocorticoid metabolites stabilize following the transition of free-ranging orphaned wild polar bear cubs into human care

Relocating free-ranging animals to human-care facilities can enhance survival when individuals are unlikely to survive in the wild. Between 2015 and 2017, six orphaned polar bear ( Ursus maritimus Phipps, 1774) cubs from northern Manitoba were transferred to the Assiniboine Park Zoo in Winnipeg, Manitoba. To assess their physiological response to relocation, fecal glucocorticoid metabolites were measured to determine the timing and extent of their adjustment to human care. Daily fecal samples ( n = 822) were collected from six cubs-of-the-year over a period of 180 days post-arrival. Biochemical and biological validation indicated that a cortisol antibody-based enzyme immunoassay was a robust technique for quantifying changes in fecal glucocorticoid metabolites in polar bear. Linear-mixed models accounting for days since arrival, body condition, and individual identity showed that fecal cortisol metabolites decreased to a mean of 28.5 ng/g approximately 12 days after transfer. These results indicate that with proper care and nutrition, orphaned polar bear cubs can rapidly adjust to living under human care within 2 weeks of relocation. Although there are several challenges to using fecal hormone metabolites to measure stress physiology in wildlife, they can still offer insights into how animals adapt to novel environments. As human–wildlife conflicts are expected to increase, establishing validated monitoring techniques for physiological acclimation will support the welfare and management of free-ranging animals transferred into human care.