HOFFMEISTER b MOHR: ILLINOIS MAMMALS 3 



edges, the number per acre may be even greater. Of this num- 

 ber, about 95 per cent are small mammals — chipmunk size or 

 smaller. As the hiker wanders through a forest or crosses a 

 brushy field, he may walk near hundreds of these small animals 

 without being aware of them. 



Habitats. — Each type of habitat has its characteristic deni- 

 zens. Under the forest floor may be shrews, moles, and voles. 

 On the forest floor may be skunks, raccoons, foxes, opossums, 

 white-footed mice, and chipmunks. Above the forest floor may be 

 flying squirrels, tree squirrels, and various kinds of bats. By 

 probing into the leaf mold on the forest floor, one may find the 

 intricate maze of tunnels used by shrews and voles; by breaking 

 open or turning over a decaying log, one may discover the nest 

 of a white-footed mouse or a pine vole; or, by probing into an 

 old woodpecker hole high in a tree, one may arouse a flying 

 squirrel from his sleep. Mammals characteristic of the Illinois 

 forest are shown in fig. 1. 



In a meadow or fencerow may live one or more coyotes, red 

 foxes, striped skunks, cottontails, woodchucks, weasels, and 

 smaller animals. If one looks closely in the grass, he may find 

 signs of the prairie vole, the least shrew, the thirteen-lined 

 ground squirrel, and the deer mouse. Some mammals character- 

 istic of this habitat are shown in fig. 2. 



In houses built in the water of lakes, marshes, or streams live 

 muskrats and beavers. At the edges of streams and lakes, one 

 may see tracks of raccoons, minks, and muskrats. Some mam- 

 mals characteristic of this habitat are shown in fig. 3. 



Many wild mammals are active principally at night; hence, 

 most people are unaware of their presence and unfamiliar with 

 the places in which they live. The comparatively large noc- 

 turnal mammals — as raccoons and opossums — are occasionally 

 encountered by day, but the more abundant, small nocturnal 

 forms such as shrews and mice are seldom seen. Most squirrels 

 are active and above ground during the day and for this reason 

 are seen more often than most other wild mammals. Fox squir- 

 rels in the woods are obvious during the daytime as they hunt 

 among leaves on the ground; but flying squirrels, which may be 

 just as numerous, are seldom seen because normally they sleep 

 all day. Shrews, voles, and other mice are easily overlooked be- 

 cause they spend much of their lives in their burrows and nest 

 chambers. 



