Social play and rank order in rhesus monkeys (Macaca mulatta.

Social play is indispensable for adequate social development. Several authors have described a correlation between a mother's rank in the hierarchy and the rank of her infant. How the mother's rank is passed on to her infant was investigated. Social play in particular was studied. Social play among group members of rhesus monkeys (Macaca mulatta) was quantified in the laboratory. The group initially consisted of one adult male, six adult females and two infants. Four additional infants were born during the study period, all females. For each mother, social rank and order of giving birth was identical. There was a positive correlation between the social rank of the mother and the frequency of play. For the younger infants, this was not significantly due to age. Most play occured with the infant of the next (higher or lower) rank. The results suggest that both the amount of play and the partner's rank predispose the young monkey to assume its mother's rank.