Noun | 1. | ![]() mammal genus - a genus of mammals family Heteromyidae, Heteromyidae - small New World burrowing mouselike rodents with fur-lined cheek pouches and hind limbs and tail adapted to leaping; adapted to desert conditions: pocket mice; kangaroo mice; kangaroo rats dwarf pocket rat, kangaroo mouse - small silky-haired pouched rodent; similar to but smaller than kangaroo rats |