Macaques (Macaca) are the most geographically widespread and behaviourally diverse primate genus, and although macaque species share the same basic social structure, they display broad interspecific variation in patterns of social behaviour. Based on these patterns, macaque species have been arranged along a 4-grade scale for social style. At one end of the scale, there are grade 1 species (e.g., Japanese macaques) that have highly hierarchical and despotic social systems, and at the other end, grade 4 species (e.g., Tonkean macaques), that have more relaxed and egalitarian social systems. In this study, the play fighting of juvenile Tonkean and Japanese macaques was compared to determine whether or not play behaviour co-varies in a manner similar to that of adult social behaviour. As predicted, Tonkean macaques exhibit a relatively cooperative style of play fighting, whereas Japanese macaques exhibit a relatively competitive style of play fighting. / x, 174 leaves : ill. ; 29 cm. --