378 TROPICAL AMERICA AND ITS ANIMALS 



internal structure of sloths is in many respects as remarkable as their external 

 appearance. The windpipe is apparently too long for the neck, which accounts for 

 the facility with which they turn their heads, and, as in some birds, forms a loop. 

 The neck does not contain the same number of vertebrae in all the sloths. Most 

 mammals have only seven neck-vertebrae, but the three-toed sloth possesses nine, 

 although the ninth, and sometimes also the eighth, is provided with a pair of small, 

 independently moving ribs not joined to the breast-bone. It might have been 

 thought that this extra number of vertebrae had something to do with the flexibility 

 of the neck of the sloths, were it not that the two-toed sloths have the ordinary 

 number of seven vertebrae sometimes reduced to six. 



Besides the number of the vertebras of the neck and the number of toes on 

 the feet, the three-toed sloths are distinguished from the two-toed species by the form 

 of the first upper tooth. One species of the former group (Bradypus tridactylus) 

 inhabits the drier parts of the forest, while a second, distinguished by a long, tan- 

 coloured stripe between the shoulders, prefers permanently flooded areas. The 

 latter species (B. infuscatus), called by the natives the sloth of the flooded country, 

 is distinguished by being able to swim. The two-toed sloths, which have only 

 two toes on their fore-feet but three on their hind-feet, are distinguished by their 

 long, thick, and almost tusk-like first upper and lower teeth. One of these, 

 Hoffmann's unau (CJiolaepus hoffmanni), has been heard to utter various sounds such 

 as a sheep-like bleating and a loud snorting. This species, which has only six 

 vertebras in the neck, is confined to Brazil, while the common unau (C. didactylus), 

 which has seven neck-vertebrae, inhabits Ecuador and Costa Rica. 



The ant-eaters, which form the third family of edentates, although 

 Ant-Eaters. . J ~ 



very different from the sloths in external appearance, are yet closely 



allied. They live, however, exclusively on insects, and are adapted in a remarkable 

 way for that sort of nourishment. They have unusually elongated heads with 

 tube-like mouths, through the small aperture of which they protrude and with- 

 draw the long, sticky tongue. The large, bent claw of the long middle toe of 

 the fore-feet serves for scratching up insects buried in the ground or hidden beneath 

 the bark of trees, while the long viscid tongue conveys them into the mouth. 

 Compared with this large middle toe, the other toes are small and in some cases 

 rudimentary. But while the toes of the fore-feet are irregular, the four or five toes 

 of the hind-legs, which are as long as the fore-legs, are of more or less equal size, 

 and provided with claws of equal length. One species of ant-eater has feet 

 somewhat like those of a sloth, adapted for climbing trees. The second also climbs, 

 and, like the first, has a long prehensile tail. The third and largest species, on the 

 other hand, lives entirelj* on or in the ground, and its tail though long is non- 

 prehensile. 



The great ant-eaters Myrmecophaga, locally known in Paraguay as yurumi, 

 and in Surinam as tamanoir, inhabit the tropical regions of South and Central 

 America, where they live either in river-marshes or forest-swamps, and are nowhere 

 numerous. They are the largest members of the family, attaining a length of about 

 48 inches exclusive of the tail, which may be 3 feet in length. The position of the 

 toes and the powerful claws might lead to the belief that these ant-eaters, which 

 generally move at a trot and, when pursued, at an awkward gallop, are burrowing 



