The effects of rearing conditions on grooming and play behaviour in captive chimpanzees

The effects of maternal and peer separation during infancy and juvenescence on adolescent and adult chimpanzee behaviour were studied. The aim was to provide an insight into the social development of the species and to investigate human influence on this process. Forty-three adolescent and adult chimpanzees (Pan troglodytes), from a variety of backgrounds, were studied at five zoos in the UK. Details of play and grooming interactions were recorded. Competence at initiating, maintaining and contributing to play and grooming interactions was assessed. It was predicted that, regardless of their present environment, captive chimpanzees that were reared without their mother would be less competent and complex in these social abilities than mother-reared chimpanzees. Results indicated that the chimpanzees' social skills showed few detrimental effects of maternal separation. Nevertheless, individuals that had been human-reared demonstrated more unsuccessful initiations of social interactions and fewer polyadic grooming interactions than their mother-reared peers. Therefore, rearing background may have only a limited effect on adult chimpanzees' social competence. Adult chimpanzees that were hand-reared or nursery-reared may be exhibiting a recovery of their social skills, or they may be unaffected by their rearing background, alternatively, the effects of rearing may have been masked by more significant factors, such as current management.