Species vary significantly in terms of the association patterns of individuals, on who interacts with whom within a social unit and how, on who mates with whom, and on who cares for dependent offspring and to what extent.
We study this diversity of social systems on three levels: describing component patterns through long-term demographic and behavioral data, examining ultimate and proximate determinants of the individual components, and the consequences of individual social factors for individual health and fitness.
By comparing sympatric species in Madagascar and Peru, we obtain additional insight into the social evolution and complexity of primate (and predator) societies.