Temporal patterns of den use suggest polygamous mating patterns in an obligate monogamous mammal

Mating systems in animal societies contain both social and genetic components. Deviations between these components may have important ramifications for our understanding of the evolution of reproductive strategies and their ecological correlates. However, although there is ample evidence for discrepancies between genetically assigned paternities and social associations in birds, relatively few studies have documented such differences in mammals. Moreover, few studies have addressed how deviations between social mating associations and mating activities influence male and female resource utilization patterns. The aardwolf, Proteles cristatus, is a socially monogamous hyaenid that exhibits polygamous mating behaviour. We show that temporal patterns in aardwolf den use, an important resource for protecting offspring, relate to predictions from polygamous mating rather than social monogamy. Males used more dens, changed dens more frequently and stayed in dens for shorter periods than females during both wet and dry seasons. We suggest that lower male den fidelity is caused by males trying to maximize female encounters and to monitor female activity, or that it is a nonadaptive behaviour related to elevated androgen levels. Our results did not point to territorial defence or space use optimization causing the observed sex differences, as we found no sex or seasonal differences in the spatial patterns of utilized dens. We suggest that aardwolves may have been ecologically constrained to exhibit social monogamy but that polygamous mating is maintained through extrapair copulations. We recommend that the evolutionary stability of these two conflicting strategies of male fitness maximization is further investigated.