Comparisons of Activity Budgets, Interactions, and Social Structures in Captive and Wild Chimpanzees (Pan troglodytes).

Chimpanzees in zoos with sufficient and appropriate environmental enrichment devices are expected to exhibit behaviors, interactions, and societies similar to those in the wild. In this study, we compared the activity budgets of each observed behavior, characteristics of social grooming, and social networks of captive chimpanzees at Tama Zoological Park (Tama) with those of wild chimpanzees at Mahale Mountains National Park, Tanzania (Mahale), and tested our predictions. We surveyed 16 chimpanzees in both Tama and Mahale and recorded the behaviors and individuals in proximity of each focal individual and social grooming the focal individuals participated in. The proportion of time spent collecting foraging was significantly lower in Tama than in Mahale. Additionally, the percentage of mutual grooming was much higher in Tama than in Mahale. All focal individuals in Mahale performed mutual grooming interactions, including grooming handclasp (GHC) but this was not observed in Tama. The result of a high rate of mutual grooming in chimpanzees in Tama without GHC and the finding that individuals forming the core of their social network are sex independent suggest that chimpanzees placed in an appropriate environmental enrichment have idiosyncratic grooming or social features, even in captivity.