Season but not sex influences burrow length and complexity in the non-sexually dimorphic solitary Cape mole-rat (Rodentia : Bathyergidae)

Abstract

Little is known about how environmental factors such as season influence burrowing activity, burrow structure or reproductive behaviour in subterranean mammals. We excavated burrow systems of male and female Georychus capensis, a solitary, subterranean rodent, in winter (wet season) and summer (dry season) to investigate whether any seasonal differences due to putative mate-seeking behaviour of males were apparent. Burrow structure did not differ between sexes, but did differ between seasons. For both sexes, summer burrows were shorter in length and covered a smaller area but explored the surrounding environment more efficiently than did winter burrows. Summer burrows had fewer mounds present indicating less expansion of the burrow systems in this season. We discuss these differences in exploration and use of the environment between seasons but not between sexes in terms of mating strategies of G. capensis and observed levels of sexual dimorphism in our populations. This study supports recent concepts regarding female competition and selection that may favour the expression of female exaggerated traits, which affect a female’s ability to acquire reproductive resources that often appear similar to that selected for by males.