Activity Patterns of Kangaroo Rats — Granivores in a Desert Habitat

Kangaroo rats (Dipodomys, Heteromyidae) are nocturnal, facultatively bipedal, burrow-dwelling rodents, inhabiting arid and grassy habitats in western North America (Genoways and Brown 1993). The family Heteromyidae consists of six genera, of which pocket mice (Chaetodipus and Perognathus) and kangaroo mice (Microdipodops) are sympatric with kangaroo rats in deserts, and are to some degree their competitors. The approximately 20 Dipodomys species (Williams etal. 1993) are very similar in appearance, but vary about fourfold in body mass from the smallest species (D. merriami and D. nitratoides) to the largest (D. ingens). Notable features of all kangaroo rats include large hind feet (which they use for rapid, bipedal, saltatory locomotion), tail substantially longer than the body, and large heads housing enormous tympanic bullae.