MAMMALS AS NEST BUILDERS 131 



example of the dormouse, the animal constructs 

 a summer and a winter nest ; the former being 

 built within the bole of a tree, or beneath a log 

 or some other similar site, while the latter is situated 

 underground. The white-footed mouse (Cricetus 

 leucopus), another inhabitant of North America, 

 also builds a nest, sometimes measuring a foot 

 across, which is frequently suspended from the 

 branch of a tree at an elevation varying from five 

 to fifteen feet above ground, and is composed of 

 moss and strips of bark. In some parts of its 

 habitat, however, the animal makes its home 

 underground. 



Many other species of the mouse tribe build 

 nests ; the short-tailed field vole (Microtus agrestis), 

 for instance, makes a residence, composed of moss 

 and leaves, which is usually concealed beneath a 

 tuft of grass ; while the meadow vole (M. riparius), 

 of North America, resorts to the curious practice 

 (during the winter months, and in the northern 

 regions of its habitat) of constructing its nest upon 

 the ground and allowing itself to be covered up 

 with snow ; the heat which generates from its 

 body melting the under surface of the snow, so 

 that in due course a dome- shaped roof is formed 

 above its snelter. 



The aquatic rodent of South America known 

 as the coypu rat, a species which grows to a length 

 of two feet from the tip of its nose to the root of 

 its tail, and is frequently exhibited by showmen 

 hi this country as a monster sewer rat, will some- 

 times erect a platform-like nest amidst the rushes ; 



