Sexual Segregation in Ungulates: New Directions for Research

Abstract

We reviewed the literature on sexual segregation in polygynous ungulates in an effort to clarify terms and concepts, summarize recent information that supports or discredits three broadly defined hypotheses, and suggest directions for future research that should help resolve when and why the sexes segregate in these large mammals. The hypotheses discussed include those based on intersexual differences in energetics and security (reproductive-strategy hypothesis), body size dimorphism and dietary requirements (sexual dimorphism-body size hypothesis), and social mechanisms (social-factors hypothesis). These hypotheses represent ecological, physiological, and social perspectives and are not mutually exclusive. Most evidence reviewed supported the reproductive-strategy hypothesis. Less support was available for either the sexual dimorphism-body size hypothesis or the social-factors hypothesis. Nonetheless, most available evidence is provided by field studies that contend with many confounding variables. We suggest several areas of future study that may serve as critical tests and are likely to be productive in resolving why sexual segregation occurs in polygynous ungulates.