The problem of adult play fighting: A comparative analysis of play and courtship in primates

Although play fighting, like play generally, is predominantly a feature of the juvenile phase, such behavior persists in the adults of many species. T here are two major contexts in which adults engage in play fighting - with juveniles and with other adults. The least attention has been given to adul t-adult play. However, one pattern that has been noted by several authors i s that the most commonly occurring context of adult-adult play fighting is during courtship, and that this is more likely to occur in solitary species . Supposedly, such play could function to overcome the aggressiveness of po tential pairmates unfamiliar with one another, or as a means of evaluating mate quality by one or both partners. By contrasting the presence and degre e of play fighting during courtship with the degree of male-female familiar ity, the hypothesis that the former is influenced by the latter is tested. Data on 35 species of primates, from 15 families, were compiled from the li terature and compared using a method of independent contrasts that incorpor ates information on phylogenetic relationships. A significant regression wa s found, with the degree of male-female familiarity accounting for 40% of t he variance in courtship play. Therefore, our data support the hypothesis t hat play fighting in courtship is influenced by male-female patterns of ass ociation. However, the data also indicate that other factors must influence the occurrence of play fighting amongst adults, not only during courtship, but also in nonsexual contexts. The broader context of adult-adult play in mammals is discussed.