Distribution and Natural History of Eligmodontia dunaris: An Endemic Small Rodent of the Atacama Desert (Chile)

Eligmodontia dunaris is a small rodent endemic to the Atacama Desert, discovered in the Los Choros dunes (La Higuera, Coquimbo Region, Chile). This study documents new records of the distribution, as well as relevant data on the natural history of this species. Records of geographic distribution were obtained in the field and from published data. The standardized number of captures was calculated by the IDR index. The ability to concentrate urine was evaluated using the RMT renal index. Reproduction and development data were obtained from pregnant females in the field and from animals that mated in the laboratory. Fourteen new locations between the type locality “Los Choros” (Coquimbo Region) and “Diego de Almagro” (Atacama Region) were recorded. In all these localities, captures of E. dunaris were low, except during periods of the flowering desert. In the laboratory, this rodent had two to three consecutive litters in a single breeding season, producing three to five pups per litter. Renal indices measured in five adult specimens (RMT = 7.9 ± 0.8) indicated that E. dunaris can concentrate urine around 4059 ± 120 mOsm/kg. These results may suggest that this species has developed physiological and ecological strategies to colonize the extreme arid environments of northern Chile, allowing it to spread across 11,267 km2 in the Atacama Desert.