1356 THE RODENTS 



The Bolivian cavy (C. boliviensis), which is of rather smaller size 

 avy than the restless cavy, is interesting from its habitat. It lives among 

 the higher regions of the Bolivian Andes at elevations of from ten to twelve thou- 

 sand feet; dwelling in large societies, and forming burrows which completely under- 

 mine the whole ground in certain districts. In color this species has the fur of the 

 upper parts gray, with a yellowish tinge, while the throat and under parts are 

 white, and the feet whitish. The incisor teeth are orange in front. 



The last species of the genus that we shall notice is the rock cavy 

 avy (C. rupestris], differing from those mentioned above by the extreme 

 shortness of its claws, which scarcely project beyond the toes. It has the fur gray- 

 ish above, and whitish beneath. This species inhabits rocky districts in certain 

 parts of Brazil, dwelling in cracks and crevices, and not constructing burrows. It 

 is much hunted by the Indians, and it is known to them as the hoki. 

 p . The Patagonian cavy, or mara (Dolichotis patachonica) , is readily 



Cavy distinguished from the true cavies by jts longer limbs and ears, and 

 the presence of a short tail, which is always turned to one side. Its 

 skull is characterized by the extreme narrowness of the front portion of the palate; 

 this being carried to such an extent that the premolar teeth of opposite sides are 

 actually in contact at their front edges. In length it is from thirty to thirty-four 

 inches, and it stands about thirteen inches at the shoulder. Its fur is thick and 

 crisp, and of a grayish color on the upper parts, while on the flanks it becomes rusty 

 yellow, and beneath white. The rump is black, with a broad transverse band of 

 white running from the hocks to just above the tail, and the limbs are rusty yellow, 

 but grayish in front. The hair of the throat is elongated into a fringe. Both in 

 habits and general appearance the mara has a superficial resemblance to the hare, 

 but the legs are longer and the ears shorter and wider. It inhabits not only the 

 barren country from which it derives its name, but likewise extends northward into 

 the grassy pampas of Argentine, where it ranges as far as Mendoza, in latitude 33 

 30'. On the Atlantic coast, however, where the climate is moister, it only ranges 

 as far north as 37 30'; while its extreme southern limit is about the forty-eighth 

 parallel. 



Absolutely dry and more or less desert-like districts are essential to 

 the well-being of the mara, and it is probable that its original home 

 was the Patagonian wastes. In Patagonia the mara is so common as to form almost 

 a characteristic feature in the landscape, Darwin observing that it is usual "to see 

 in the distance two or three of these cavies hopping one after the other in a straight 

 line over the gravelly plains, thinly clothed by a few thorny bushes, and a withered 

 herbage." Generally these Rodents are found either in pairs or in parties of from 

 four to eight individuals, but occasionally in large flocks of thirty or forty. They 

 live in burrows, generally excavated by themselves, and differ from the other cavies 

 in being diurnal. To protect its eyes from the glare of the midday sun, the mara 

 has well-developed eyelashes, which are wanting in its nocturnal allies. In dispo- 

 sition these cavies are extremely shy and timid, taking to flight at the least alarm, 

 and generally trusting to their legs, rather than to the shelter of their burrows, for 

 safety. Their food consists chiefly of grass and the roots and stems of such other 



