Space use and the evolution of social monogamy in eastern rock sengis

Limiting resources often differ between males and females. Reproductive success in females is constrained by resources such as food and shelter, while the availability of receptive females determines male reproductive success. In addition to limiting resources, low intra-sexual tolerances among females can affect their spacing. High intolerances coinciding with low population densities have been suggested as a cause for the evolution of monogamy in mammals, but the evidence for female intolerance is limited. We investigated long-term space use patterns (measured as home range sizes and centers of activity) in a wild population of eastern rock sengis (Elephantulus myurus) from Limpopo, South Africa. Between March 2012 and March 2016, we recorded capture locations for 93 sengis and home range size for 22 sengis and evaluated the contributions of study year, sex, and season on these measures. Sex had no significant effect on home range size, but ranges were significantly greater during the breeding compared to the non-breeding season, consistent with the increased energetic demands during reproduction. We found corroborative support for the role of energetic demands on home range size fluctuations. The activity centers of female–female dyads were further apart than those of male–male or mixed-sex dyads, suggesting lower female–female tolerances in the study species. Our results offer evidence that intolerances may affect female spacing behavior and may have contributed to the evolution of monogamy in sengis.