240 



FIRST LESSONS IN ZOOLOGY. 



muscles of the fore feet in the armadillos are specially mod- 

 ified so as to secure great strength for digging, and the 



FIG. 39. Nine-banded Armadillo. 



large claws are used like miniature picks in boring into 

 the tough clay." 



The Gnawers. Weak in bodily strength and usually di- 

 minutive in size, with brains inferior in capacity to those 

 of higher mammals, the gnawers or rodents, early choosing, 

 so to speak, the trade of carpenters and builders, have in- 

 creased and multiplied until their order is more widespread 

 and more numerous in species than any other order of 

 mammals. They live in every variety of station, burrow- 

 ing in the earth, making their homes in streams and ponds, 

 or taking up their abode in trees. Dissimilar as their sta- 

 tions are, they all agree in having the same kind of teeth, 

 and in getting their food in much the same manner. 



They differ from animals of other orders in the large in- 

 cisor teeth and in the absence of canine teeth (Fig. 240). 

 Their feet are adapted for walking, climbing, or burrow- 

 ing, the claws being long and curved. A peculiarity in the 

 incisors is that they grow out as fast as they are worn 

 down ; this is due to the fact that the pulp is persistent ; 

 the enamel in front causes them to wear away behind so 

 that they are chisel-shaped. The species are prolific, live 

 mostly on vegetable food, and are of small size; the musk- 

 rat, beaver, and capybara being the largest members of the 

 order. 



With rare exceptions, rodents feed on the stalks, roots, 

 and leaves of plants, as well as seeds and fruit. The hares 



