Muridae - Mice and Rats
Muridae is the largest family of North American mammals, and certainly the largest family in Idaho. They range in size from the very small western harvest mouse weighing ½ of an ounce, to the muskrat, which may weigh 4 pounds. They occupy a great diversity of habitats from the driest area in Idaho to living in a totally aquatic environment. They are generally, non-hibernators, most use burrows for shelter and protection against predators, and they do not have external cheek pouches. Family Muridae is divided into two major groups on the basis of differences in their teeth and body form: the cricetines and the microtines. Cricetines include the harvest mice, deer mice, grasshopper mice and woodrats. They are characterized by having rather long tails, large eyes and ears and cheek teeth with prominent cusps , and most are active at night (nocturnal ). Many of these mice are good climbers. The Microtine group includes voles and lemmings. They have stouter, heavier-appearing bodies, and small, inconspicuous eyes and ears, and they have shorter tails. Their cheek teeth are more flattened on top. They tend to be active during day and night, and their populations exhibit dramatic fluctuations; and some exhibit cyclic population fluctuations.
- Jumping mice
Family Zapodidae is a small family consisting of only 4 species. Only one species, the western jumping mouse occurs in Idaho. As their name implies, they have tremendous leaping abilities, much like kangaroo rats. However, they are not closely related to kangaroo rats or pocket mice, but rather they seem more closely related to jerboas of the "Old World" deserts.