X. THE GNAWERS 



A large and interesting group of animals are called 

 rodents, or gnawers, from the fact that they are provided 

 with powerful chisel-like incisor teeth (Fig. 58) to enable 

 them to cut trees, limbs, and nuts, upon which they live or 



Fig. 58.— Incisor Teeth of a Rodent. 



depend. They have no canine teeth, which form so promi- 

 nent a feature in the carnivorous animals. The molar 

 teeth are flat, and the lower jaw is so articulated that it 

 moves forward and back instead of up and down. 



Animals of this kind are typified in the squirrel, which 

 is a familiar object, sitting upright and gnawing into a 

 hard nut with its powerful teeth. The beaver, which 

 chisels down large trees, is another member of this group. 



The rabbit and hare are familiar examples of rodents. 

 The incisor teeth (Fig. 59) of these animals are sharp and 

 powerful, making them troublesome to the farmer from 



HOLDER, MAMMALS — 6 



8i 



