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

SIMPLE SUMMARY: For chimpanzees in zoos, the key aim of environmental enrichment is to enable them to exhibit behaviors, interactions, and societies similar to chimpanzees in the wild. A comparison of observational data, showed that the proportion of their time spent on collecting foraging was significantly lower in captive chimpanzees (located in Tama) than in wild chimpanzees (located in Mahale), but no significant difference was found between the two groups in terms of the proportion of their total time spent collecting, extractive, and hunting foraging. The percentage of time spent performing mutual grooming was much higher in Tama than in Mahale. Males, but not females, in Mahale formed a core social group, but no sex-specific differences were found in Tama. The multiple artificial feeders allowed chimpanzees in Tama to spend more time on extractive foraging to achieve a similar proportion of time on foraging as compared with that of the wild chimpanzees. The environmental enrichment for chimpanzees in Tama can be considered to be successful. ABSTRACT: 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.