Spatial relationships between burrows of an insular population of Dipodomys merriami

For semi-fossorial rodents, descriptions of the distribution and use of burrows can advance in understanding the spatial and social organization of their population. This study describes the use and spatial relationships between burrows of the kangaroo rat (Dipodomys merriami insularis), a subspecies that is possibly on the verge of extinction. Individuals were captured and recaptured in an area of 79.8 hectares located at San José Island, Gulf of California, Mexico, during both the breeding (BRED, from March to May) and the non-breeding (NON-BRED, from October to November) seasons of 2008. Our results show that females and males use a median of 1-2 burrows; factors such as age class, season and frequency of captures account for the number of burrows used by individuals. Few individuals shared their burrows (9.2% during BRED and 1.1% during NON-BRED). The burrows showed a clumped spatial distribution in both sampling periods. The spatial relationship between burrows is characterized by the fact that animals of opposite sex are closer to each other than same-sex individuals, and this spatial relationship between nearest-neighbor burrows is influenced by age class. Our results show that D. m. insularis displays burrow use and spatial organization patterns similar to those observed in other populations of D. merriami.