242 ANIMAL STUDIES 



dogs, ground-squirrels, and chipmunks of the terrestrial 

 species are of frequent occurrence, and of the tree-dwellers 

 the fox, gray and red squirrels are well known in many 

 sections of the United States. 



225. Insect-eating mammals (Insectivora). The shrews 

 and moles belonging to this order are representatives of a 

 large group of small animals, which, unlike the major 

 number of rodents, live on insects. The shrews, of which 

 there are several species in this country, are small, mouse- 

 like creatures, nocturnal in their habits, and hence rarely 

 seen. The moles are of much larger size, and owing to 

 their burrowing proclivities scarcely ever appear above 

 ground, but excavate elaborate burrows with their shovel- 

 like feet, devouring the insects which fall in their way. The 

 common mole (Scalops aquaticus) extends from the eastern 

 seaboard to the Mississippi Eiver, where it is replaced by 

 the prairie-mole (S. argenteus), which extends far to the 

 west, into a country inhabited by other species. 



226. The bats (Cheiroptera). The bats are also insectiv- 

 orous, but their habits are widely different from those of 

 the shrews and moles. The forearm and the fingers of the 

 fore limbs are greatly elongated, and are connected by a 

 thin papery membrane, which also includes the hind limbs 

 and tail, and serves as an efficient organ of flight. During 

 the day they remain suspended head downward in some 

 dark cranny, awakening at nightfall to capture flying 

 insects. Several species are found in this country, the 

 most common being the little brown bat ( Vespertilio fus- 

 cus), with small, fox-like face, large erect ears, and short 

 olive-brown hair. The red bat (Lasiurus borealis) is also 

 plentiful everywhere throughout the United States, and is 

 distinguished from the preceding by its somewhat larger 

 size and long reddish-brown fur. 



227. The whales and porpoises (Cete). The animals 

 belonging to this order, the whales (Fig. 135), porpoises, and 

 dolphins, are aquatic animals bearing a resemblance to fishes 



