MAMMALS 301 



tree tops feeding on green leaves. They are not entirely tooth- 

 less as the name of the order would indicate, but they are 

 nearly so. "One cannot look at a live sloth without thinking 

 that nature has but poorly equipped this animal to live in this 

 murderous world. Its countenance is a picture of complete and 

 far-reaching stupidity, its bodily form the acme of four-footed 

 helplessness. It can neither fight, hide, nor run away. It has 

 no defensive armor, not even spines. It is too large to live in a 

 hole in a tree, and too weak to dig a burrow in the earth. It 

 is too tired to walk on its feet, as the monkeys do, so through- 

 out its queer life it hangs underneath the branches of the trees 

 in which it finds its food." (Hornaday.) 



The armadillos occur principally in South America, but one 

 species, the nine-banded armadillo, Tatu novemcinctum, is 

 found also in Mexico, Texas and Arizona. They are covered 

 with hard bony plates which form a protecting case for all 

 parts of the body. When attacked the animal draws in its 

 legs and rolls up into a ball leaving exposed to its enemy only 

 this bony shell. 



The ant-eaters are also confined to South and Central 

 America. The small mouth situated at the end of a long 

 slender beak is entirely toothless. They devour great quan- 

 tities of ants and thus help to reduce the numbers of these 

 insects which are often great pests in tropical countries. 



To the order Sirenia belong the manatees, or sea-cows, and 

 the dugongs. These are aquatic, seal-like animals with the 

 fore legs reduced to a pair of flippers and the hind legs wanting. 

 One species of manatee, Trichechus latirostris, is still found off 

 Florida, and others occur in the warm waters of the islands and 

 along the coast of Mexico, Central and South America. The 

 great Arctic sea-cow, Hydrodamalis gigas, once occurred 

 abundantly in the Bering Sea region where it reached a length 

 of twenty to thirty feet. The natives and the whalers used 

 it for food until it was practically exterminated about 1780. 

 The last animal of this species seen was killed in 1854. 



The Cete are an order of aquatic mammals all more or less 

 fish-like. The whales, dolphins and porpoises belong to this 

 order. In all, the posterior limbs are so reduced that they 



