Enrichment study in three captive polar bears (Ursus maritimus) at Aalborg Zoo

Polar bears (Ursus maritimus) are vulnerable to environmental changes, which often leads to the development of stereotypical behaviour in captivity.Multiple studies hadshownthat the usage of enrichment could reduce stereotypicalbehaviour in captive animals thereby, improving their welfare. When choosing enrichments,it is necessary to examine the individual personalities, since differences in behavioural reaction norms of the medianscould lead to different preferences among animals regarding the types of enrichment used.This study investigated the behaviour of three polar bears (one adult female and her two cubs)at Aalborg Zoo and whether different types of enrichment would have an impact on their behaviour and reduce stereotypes. Furthermore, this study also investigatedwhether the three polar bears differed in their behavioural reaction norms, behavioural instability, and behavioural diversity. No differences were found in behavioural reaction norms between the enrichment days and control days, except for, the skewness and kurtosis. The mother bear was observed to have more stereotypical behaviour than her cubs, which correlated well with her low behavioural diversity index. A significant difference in behavioural reaction norms was found between the mother and her cubs although, there was no difference between the cubs’ reaction norms. So, no significant differences in behavioural reaction normsand behavioural instability were found between thetwo cubs.