Spatial grouping in behaviourally solitary striped hyaenas, Hyaena hyaena

We investigated spatial organization and patterns of interaction in a population of the little-known striped hyaena, Hyaena hyaena. We use the resulting data to test hypotheses of group formation that predict that female striped hyaenas will be solitary in response to overdispersion of food resources and males will be solitary in response to overdispersion of females. Based primarily on anecdotal or historical information, striped hyaenas have been described as solitary. We show that, as predicted, striped hyaenas of both sexes are behaviourally solitary. However, they form stable, polyandrous spatial groups composed of multiple males and a single female. We suggest that male coalition formation may be the result of male strategies to optimize trade-offs between the number of female ranges defended and the effectiveness of that defence when females are solitary and maintain large territories. Nevertheless, the joint male defence of a territory (of any size) containing only a single female would not be predicted by any major hypothesis for the evolution of group living, in this or any other species.