Great Basin Naturalist Memoirs


The functional morphology of desert heteromyid rodents (Perognathus, Dipodomys, Microdipodops) is reviewed with considerable new information provided. Specific attention is given to the interaction of anatomical structure and the behavioral and ecological patterns of these rodents.
Inflation of the auditory bullae, although apparently related to improving hearing, is also shown to directly impact the structure and function of the feeding apparatus in desert heteromyids. The mechanics of high speed pouching behavior is Dipodomys deserti as well as the rates of digging activities of various heteromyids are described using data from slow motion films. The biomechanical consequences of cheek pouch loading for body size and locomotor behavior yield theoretical predictive models concerning interspecific differences in foraging behavior, dietary preference, and microhabitat selection.
Structural modifications of the forelimb associated with use of external cheek pouches reduce the mechanical competence of these limbs for shock absorption during fast quadrupedal running. The relative size of various front and hind limb segments are correlated with quadrupedal, tripodal, and bipedal gaits in heteromyid rodents. The interdependence of body balance, gait, and speed are examined in Dipodomys merriami. Factors possibly contributing to the origin of bepedalism in rodents are reviewed and discussed.