Using sexual dimorphism and development to reconstruct mating systems in ancient primates

Male and female interactions are often reconstructed for fossil primates for a number of reasons: To argue that a particular social system is the primitive or ancestral form; to investigate the evolution of mating systems; to examine the potential for infanticide and female counter-strategies; and to study how behaviors like sexual selection and mate choice may have influenced primate speciation. Behavioral reconstruction from fossils is extremely limited. Yet, sexual dimorphism has been used since the 1980s to infer polygynous mating systems in early anthropoids like Aegyptopithecus. Rates of growth can be studied from fossil remains using a number of techniques. Despite extensive study, living primates show no good link between degree of dimorphism and social structure. Group composition can be analyzed for fossil primates (including humans) in a few rare cases. In addition to maturation rates in fossils and comparative soft-tissue evidence from living primates, group composition allows a rough outline of social structure to be reconstructed for a limited number of fossil primates. Much more attention has been directed to fossil humans, especially given the existence of multiple hominid species, and sympatry between some early species. The degree of sexual dimorphism in fossil hominids has been used to document hominid status itself and increasing hominization through time, and to infer behaviors such as pair-bonding.