Evolution of Primate Social Systems

Abstract

We review evolutionary processes and mechanisms that gave rise to the diver- sity ofprimate social systems. We define social organization, social structure and mating system as distinct components ofa social system. For each com- ponent, we summarize levels and patterns of variation among primates and discuss evolutionary determinants ofthis variation. We conclude that conclu- sive explanations for a solitary life and pair-living are still lacking. We then focus on interactions among the 3 components in order to identify main targets ofselection and potential constraints for social evolution. Social organization and mating system are more closely linked to each other than either one is to social structure. Further, we conclude that it is important to seek a priori measures for the effects ofpresumed selective factors and that the genetic con- tribution to social systems is still poorly examined. Finally, weexamine the role of primate socio-ecology in current evolutionary biology and conclude that primates are not prominently represented because the main questions asked in behavioral ecology are often irrelevant for primate behavior. For the future, we see a rapprochement of these areas as the role of disease and life-history theory are integrated more fully into primate socio-ecology.