178 



Order RODENTIA 



Fig. 97. — Pine vole. 



median projection. Dental formula: I 1/1, C 0/0, Pm 0/0, 

 M 3/3. 



The pine vole, fig. 4, differs from other voles in having a 

 shorter tail, glossy, velvety fur, two pairs of mammary glands, 

 and a broad interorbital region of the skull. It differs from the 

 bog lemming in possessing ungrooved and narrower upper 

 incisors and glossy brown hair that is velvety like that of a mole. 



Life History. — The pine vole occurs in woods, orchards, and 

 even in grassy fields some distance from woods. It lives in leaf 

 litter or grassy mats. It makes an extensive network of under- 

 ground burrows, which it uses in searching for food, in resting 

 or nesting, and in rearing its young. Along these underground 

 burrows, fig. 1, it feeds on tubers and succulent roots, grasses, 

 seeds, and roots of trees. The pine vole spends much less time 

 in surface runways than do other Illinois voles. It makes a 

 globular nest of dead leaves and grasses in a burrow a few 

 inches below the surface of the ground, under the roots or the 

 stump of a tree, or in a log. 



Breeding of the pine vole extends from March to November. 

 Usually there are three or four young in a litter. Although 

 helpless at birth, the young can gather food for themselves at 

 about 2 weeks of age. 



The pine vole is preyed upon by foxes, minks, skunks, rac- 

 coons, and owls. 



Signs. — Tracks of the pine vole are similar to those of other 

 voles but are rarely seen because this mouse prefers to remain 

 underground. Its burrows, however, are common in some wood- 



