Space to choose: network analysis of social preferences in a captive chimpanzee community, and implications for management.

Social network analysis (SNA) is rapidly gaining popularity in primatology, but its application to the management of zoo-housed primates has been largely overlooked. Here I use SNA techniques to explore the social structure of chimpanzees (Pan troglodytes) housed in the new "Budongo Trail" exhibit at Edinburgh Zoo, UK. Given that individuals have extensive space (2332 m(2)), and access to several interconnected exhibit sections, I test the hypothesis that individuals are able to choose to interact with specific social partners. Spatial association and social interaction data were recorded from 400 focal watches on 11 individuals, and association, affiliative, and agonistic networks were constructed. Matrix correlations showed that individuals who spent time in close proximity were likely to affiliate with one another, but spatial association did not predict the frequency of agonistic encounters. Cluster analysis revealed significantly distinct sub-groups in the affiliative network (but not association or agonistic networks) in line with maternal kinship. Overall my findings support the hypothesis that the Budongo Trail exhibit facilitates the expression of social preferences, and suggests that SNA can be a useful tool to study zoo primates when proximity between individuals is not forced (i.e. in large, modern exhibits). Now that I have validated a set of SNA methods for this community, they can be used to trace changes in social dynamics over a longer time period, and ultimately assist zoo staff in their management decisions.