Family CRICETIDAE 161 



work of stems, roots, and leaves, and holds a soft Inner lining 

 of plant down, fur, or feathers. 



Young may be produced in nearly any month of the year. An 

 adult female may have several litters (potentially a dozen, but 

 probably only four or five) each year, and there are usually four 

 young in each litter. The young, blind and naked at birth, grow 

 rapidly. Females can start breeding when only 5 to 10 weeks 

 old. 



The deer mouse feeds on seeds of grasses and weeds, and on 

 berries, buds, insects, and possibly some green plants. It does 

 not hibernate. Probably it hoards some seeds in burrows or 

 tunnels near its nest for winter use. This mouse is preyed upon 

 by owls, snakes, weasels, foxes, and nearly all other Illinois fur 

 bearers. In the wild, it probably never lives for more than 2 

 years before it meets an untimely end; it may live as long as 9 

 years in captivity. 



Signs. — It is difficult to tell the footprints and droppings of 

 the various kinds of Peromyscus apart. The location of signs 

 may aid in determining the kind of mouse that made the signs, 

 as habitats of the various species differ considerably. 



Prints of the hind feet of the deer mouse are paired and those 

 of the front feet are nearly so. The sets, fig. 31, are about 3 

 inches apart when made by a mouse bounding at an ordinary 

 gait; much farther apart when made by a speeding mouse. Drop- 

 pings are brown or black and between 14 ^^^ ^ inch long. 



Distribution. — The deer mouse may be locally abundant, 

 particularly in sand prairies. Colonies probably occur through- 

 out the state. The subspecies in Illinois is Peromyscus nianicu- 

 latus bairdii (Hoy & Kennicott). The main range of the spe- 

 cies extends from Labrador to central Alaska and southward to 

 southern Mexico in the west and Tennessee in the east; the 

 range also extends down the Appalachians to northeastern 

 Georgia. 



PEROMYSCUS LEUCOPUS (Rafinesque) 



White-Footed Mouse Woodland White-Footed Mouse 



Description. — The white-footed mouse, fig. 90, has the same 

 proportions as the house mouse, but is larger. In the adult, the 

 upper parts are bright brown or fulvous, the under parts white. 

 The ears are dusky brown, with whitish edges. All four feet 



