Social evolution in mammals.

Long-term, individual-based field studies, the application of genetic techniques, and phylogenetic reconstructions have led to substantial advances in our understanding of the diversity and evolution of mammalian breeding systems and their consequences. These studies show how differences in ecology, life histories, and phylogeny affect the distributions of breeding females and breeding males; how the distributions of both sexes affect the evolution of breeding systems and the composition and kinship structure of social groups; how differences in breeding systems and the social environment that individuals encounter affect the selection pressures operating on both sexes and the evolution of their behavior, physiology, and morphology; and how these differences affect the demography and dynamics of populations and their responses to variation in density, climate, and human impact.