The Welfare of Zoo-housed Chimpanzees (Pan troglodytes) with Special Attention to Auditory Enrichment

Modern zoos house millions of wild animals but also aim to conduct animal research, educate visitors about the natural world and support conservation programmes via funding and encouraging wildlife-friendly actions by the public. However, the benefit to conservation efforts and species living in the wild, through fundraising and increasing public awareness, may come at the cost of the animals living within zoos. In this thesis I focussed on the welfare of zoo-housed chimpanzees due to their endangered status and public popularity. I investigated potential social, dietary and visitor related triggers for anxiety-related behaviours (yawning and scratching) and regurgitation and reingestion (R/R). Despite interesting trends, no immediate triggers for these behaviours were found. However, long-term data showed the frequency with which individuals engage in R/R reduced over time when part of a complex group inhabiting an enclosure encouraging natural behaviours and social dynamics. I also examined if music, frequently broadcast to captive chimpanzees, provides any enriching effect on their welfare. Both observational and experimental research suggested that whilst music does not appear to have any obvious positive welfare effects it is equally not detrimental. The final study explored whether public education, one of assumed benefits associated with having animals in zoos, is achieved via ‘Keeper Talks’. They were effective at demonstrating to adult visitors that touchscreens are an effective form of enrichment for chimpanzees but the talks had no significant effect on their knowledge of other issues covered, or any area of knowledge in young people. Further investigation showed that zoo professionals have inaccurate estimates of visitor knowledge and that assessment methods do not always align with educational goals. Overall, the findings in this thesis highlight the importance of research within zoos, which can lead to a better understanding of barriers to good animal welfare, utilisation of only positive welfare interventions and maximisation of educational potential.