Social tolerance and adult play in macaque societies: a comparison with different human cultures

Differences in play behaviour often illuminate complex ecological parameters and social differences. In primate societies, including humans, individuals acquire information through play. It is adults in every community that are most committed to managing social practices. In tolerant species, adults often participate in play to reinforce social networks and cooperation. The 20 macaque species are all organized in multimale, multifemale groups but vary along a continuum from despotic/intolerant to egalitarian/tolerant social systems. These different social styles influence a wide range of behaviours including aggression and affiliation patterns, dominance relationships, and nepotism. We tested some hypotheses by comparing play patterns in two macaque societies at opposite ends of the continuum: despotic Japanese macaques, Macaca fuscata, and tolerant Tonkean macaques, Macaca tonkeana. Our results show that these two species have striking differences in the distribution of social play according to the age and sex of the players. Our findings strongly indicate that play, a highly plastic and versatile behaviour, is sensitive to the quality of interindividual relationships of a species, thus reflecting the nature of its social network. The different patterns of macaque play show striking parallels with those from comparisons of different human cultures including the distribution of social play according to the age and gender, partner preference according to age, and permissiveness of mothers. The adult play propensity of Tonkean compared to Japanese macaques indicates that adult-adult play is a good predictor for the polarity of changes in aggressiveness between different groups separated either genetically (taxa) or culturally (ethnies).