1330 THE RODENTS 



Rodents are found in large numbers; whole tracts being frequently undermined by 

 their long and shallow burrows, of which the course is indicated by lines of hillocks. 

 They are nocturnal in their habits, feeding mainly upon the roots of plants of which 

 they are said to lay up a store. Mr. W. H. Hudson writes that on the Argentine 

 pampas wherever there is a stretch of sandy soil, or a range of sand hills, the tuco- 

 tuco is to be found; " not seen, but heard; for all day long and all night sounds its 

 voice, resonant and loud, like a succession of blows from a hammer; as if a com- 

 pany of gnomes were toiling far down underfoot, beating on their anvils, first with 

 strong measured strokes, then with lighter and faster, and with a swing and rhythm 

 as if the little men were beating in time to some rude chant unheard above the 

 surface. ' ' The tucotucos seem to be somewhat gregarious in their habits as several 

 may be often taken from a single burrow. 



Chili is the home of two species of Rodents known as cururo 



lacopus), nearly allied to the last, but distinguished by their rudi- 

 mental ears. Somewhat curiously, another nearly related form (Petromys typicus) 

 is found in South Africa, which differs from its American cousins by the harshness 

 of the fur, the shortness of the thumb, the rather bushy tail, and the partially 

 rooted molar teeth. 



THE COYPU 

 Genus Myopotamus 



Widely different in its habits from the tucotuco is the coypu (Myopotamus coypu) 

 of South America, which is one of the largest members of the order, attaining a 

 length of from twenty inches to two feet, exclusive of the tail. It belongs to a 

 group of several genera distinguished from the preceding American examples by the 

 very harsh nature of the fur, and depth of the folds of enamel in the half-rooted or 

 rootless molars. The coypu itself is characterized by the very large size of its 

 incisor teeth, and by the upper molars having two folds of enamel on each side, 

 while in those of the lower jaw there are one external and three internal folds. 

 The molars are partially rooted, and the last one is larger than either of the others. 

 The ears are of moderate size, and the tail, which is scaly, with a thin coating of 

 short hairs, is about two-thirds the length of the head and body. Each of the feet 

 has five toes, which in the hind-limb are connected by webs. The fur of the coypu 

 is long, but beneath there is a dense and soft under-fur. The color of the upper 

 parts is a mixture of dusky and brownish yellow, the sides and under parts being 

 pure brownish yellow, the tip of the muzzle and chin white, the feet dusky brown, 

 and a patch below each ear yellow. 



The coypu is found in the rivers and lakes of South America, on 

 Distribution * * 



both sides of the Andes, from Chili and Peru to about the forty-eighth 



parallel of south latitude. In the Chonos Archipelago, according to Darwin, coypu 



are found exclusively in the channels and bays separating the various small islands. 



In general appearance and habits the coypu is not unlike a beaver, being thor- 



oughly aquatic, and making its burrows in the banks of the rivers and lakes it fre- 



