Data from: Large brains and groups associated with high rates of agonism in primates

Animals living in social groups will almost inevitably experience competition for limited resources. One consequence of competition can be agonism, an activity that is not only costly to participate in at the individual level but potentially also at the group level due the detrimental effects that agonism can have on group stability and cohesion. Agonism rates across primate species have previously been associated with group size and terrestriality; therefore primates, particularly those in large groups, should develop strategies to mitigate or counter-act agonism. Here, we use phylogenetically controlled analyses to evaluate whether the known relationship between brain size and group size may partially reflect an association between agonism and brain size in large groups. We find strong positive associations between group level agonism and 2 measures of brain size (endocranial volume and neocortex ratio) in 45 separate populations across 23 different primate species. In contrast, dyadic (pair-wise) rates of agonism are inversely associated with group size and not with brain size. Moreover, we find a distinct absence of relationships between agonism and the prevalence of prosocial, cooperative behaviors. That overall rates of agonism increase but dyadic rates decrease with group size suggests that individuals in larger groups either can buffer aggression better or only species with low levels of dyadic conflict can maintain large groups

Island Life: Use of Activity Budgets and Visibility to Evaluate a Multi-Species Within-Zoo Exhibit Move.

Modern zoos strive to construct habitats which both enable and encourage animals to engage in species-specific behaviour, without compromising their visibility to visitors. Here, we present the findings of a within-zoo move to a custom-built exhibit (Islands at Chester Zoo, UK) with respect to the behaviour of four mammal species; the Sumatran orangutan (Pongo abelii), crested macaque (Macaca nigra), Malayan tapir (Tapirus indicus) and the Malayan sun bear (Helarctos malayanus). We used full activity budgets along with Compositional Data Analysis (CoDA) to gain insight into how the move to a more naturalistic exhibit influenced behaviour. Engagement in abnormal behaviour remained low during the study period for all four species, suggesting no adverse responses to the change in environment. Following the move, both the non-human primate species spent more time engaged in positive social interactions with conspecifics, highlighting the importance of social support during enclosure moves. Time spent visible to the public was largely unaffected by the enclosure move for the Sumatran orangutan, whilst the movement to a new environment increased visibility for the Malayan sun bear and decreased visibility for the crested macaque and Malayan tapir. We demonstrate the value of monitoring behaviour throughout the translocation of zoo-housed species and outline the positive behavioral impacts of providing individuals with naturalistic, species-appropriate environments