Kinship associations of a solitary rodent, Dipodomys ingens, at fluctuating population densities

The formation of kin groups is an important step in the path to evolution of sociality in mammals. We used microsatellite DNA analyses, trapping and radiotelemetry data to investigate spatial and genetic associations of the solitary giant kangaroo rat, Dipodomys ingens. We predicted that, as population densities increase, dispersal distances should decrease to form kin groups. As predicted, females decreased dispersal distances as population densities increased to form female kin clusters of related neighbours. Males also decreased dispersal distances, but only at the highest density, and they did not form kin clusters. Males seemed to adjust their home ranges to overlap unrelated females as a possible strategy to avoid inbreeding. They were not highly related to the majority of females that they overlapped, and the nearest neighbour in most cases was an unrelated female. The significant decrease in distance between female neighbours and the formation of female kin groups at high population density represents a potential increase in social interactions among these solitary rodents. Further research is necessary to determine the extent to which D. ingens is able to discriminate between kin and other familiar animals and whether they interact preferentially to facilitate the success of closely related kin.