The role of personality in welfare: how individual differences in personality influence welfare variations and response to environmental enrichment in captive Sapajus apella

This study investigates the relationship between personality, behaviour, and welfare in captive capuchin monkeys (Sapajus apella) at Bioparque Buinzoo (Chile). The main goals were to assess welfare, examine association between personality traits and abnormal behaviour, and evaluate the effects of habitat enrichment on activity levels, social interactions, and abnormal behaviours. We assessed personality using an adapted Eysenck’s PEN questionnaire, whereas welfare was evaluated through the Animal Welfare Assessment Grid (AWAG), complemented with behavioural observations. The results revealed strong connections between personality traits, behaviour, and welfare. Self-directed behaviours were significantly associated with the Introversion-Extraversion personality axis, while affiliative behaviours correlated with higher welfare scores. Contrary to expectations, Anxiety-related traits were negatively correlated with abnormal behaviour, suggesting a more complex relationship than anticipated. Individuals with lower welfare scores were less active, supporting the notion that poor welfare impacts both physical and psychological well-being. Habitat enrichment interventions produced mixed results: while inactivity decreased significantly, there were no notable changes in abnormal or affiliative behaviours. These findings indicate that while enrichment can improve activity, its design may require greater personalisation to address social and behavioural challenges effectively. This study highlights the importance of considering individual differences when planning welfare strategies. Incorporating personality assessments into environmental enrichment planning would provide a more tailored approach, better addressing the specific needs of each animal. By focusing on individual traits, welfare can be improved and foster healthy social interactions. This study also emphasizes the value of nonhuman primates as models for understanding personality and behaviour, contributing to both welfare management and species-specific biological insights.