Effect of enrichments on behavioural reaction norms of two captive polar bears (Ursus maritimus) in Aalborg Zoo, Denmark

Abstract

Polar bears ( Ursus maritimus ) are susceptible to stereotypical behaviour in captivity. Studies have found that different enrichment strategies can help activate the bears, thereby changing their behaviour and decrease stereotypies. When observing polar bears, it is apparent that individuals exhibit behaviours with different frequencies, which makes it relevant to examine if the animals have different behavioural reaction norms. This study aims to investigate the behaviour of two polar bears in Aalborg Zoo and how enrichments changes their behaviour. Furthermore, it investigates if the polar bears differ in behavioural patterns, reflecting differences in behavioural reaction norms. Although no significant differences were found, the results suggest an association between enrichments and decreased stereotypical behaviour for one bear while there was no detectable change in stereotypical behaviour for the other bear. The different reaction patterns for the two bears, may be due to different behavioural reaction norms e.g. individual differences in neophobia and exploratory behavior. In future studies presentation of the enrichment objects before the test days, may yield more heterogeneous results easier to interpret.