Intraspecific Aggression and Social Dominance

Intraspecific aggression, which links to dominance in socially integrated vertebrates, enables the struggle over limited resources to improve survival and reproduction. Studies of intrasexual competition-one of Darwin’s two mechanisms of sexual selection-typically focus on reproductive consequences of androgen-mediated, male aggression over access to females; yet, there is growing appreciation of female reproductive skew owing to competition over ecological resources, and of interactions between genetic, neural, and hormonal systems in governing aggression. Our review begins with historical, disciplinary highlights in the study of aggression, discussion of its relation to reproductive success in both sexes, and an overview of neuroendocrine mediators. We then review our own work evaluating tradeoffs in mating versus parenting effort, the integration of androgens and glucocorticoids, and findings on exceptional mammalian species that function as ‘experiments of nature’ for assessing the role of androgens in female aggression. We end by suggesting areas of future integrative study.