The upper parts are pale brownish yellow. The tail is well haired. The young are darker and grayer than the parents. Eligmodontia is distinguished by the specialization of its hind feet, inflation of the auditory bullae, and brachyodont molars. The ears of Eligmodontia are long and prominent.
Females have eight mammae.
Eligmodontia can jump and climb with amazing agility, its period of greatest activity being during the night. It is said not to dig its own burrow but to inhabit the deserted dens of Ctenomys. It also lives under old logs and bushes. It also has the unusual capability of drinking salt water, which suggests that it could utilize succulent parts of desert plants with a high salt content. Females could produce more than one litter during this period.