The effect of drought on the social structure and use of space in Cape ground squirrels, Xerus inauris

Abstract

Through changes in resource abundance, both spatial and temporal variability in environmental conditions can influence the type of sociality and life-history exhibited in a species. We documented the behavior and use of space of Cape ground squirrels, Xerus inauris, both before and during a prolonged (2-year) drought. This southern African species occurs in semiarid regions where drought is unpredictable, but not uncommon. As expected, during the drought we observed larger home ranges, lower population density and reduced breeding. However, body mass and sex ratios did not differ between conditions, and despite an obvious reduction in resources, female social groups did not disband or decrease in size. Instead, both before and during the drought, Cape ground squirrels remained in tightly cohesive social groups. We conclude that the resilient social organization in the face of dramatic changes in resource abundance reflects the great benefit of grouping as an anti-predator strategy for this species.