138 NATURAL HISTORY. 



Porcupine may destroy hundreds of trees in the course of a winter. The Urson resides in the holes 

 of trees, and in such situations, or in crevices among the rocks, the female prepares her nest, in which 

 she brings forth usually two, but occasionally three or four, young in April or May. 



FAMILY XIII. CHINCHILLIDJE (THE CHINCHILLAS). 



In the Chinchillas, which form a small family peculiar to South America, the incisor teeth are short ; 

 the molars are rootless, divided by continuous folds of enamel into transverse plates, and the two 

 series in each jaw converge towards the front ; the zygomatic arch has no angular process on the 

 lower margin ; the clavicles are slender but perfect ; the fore limbs are small, the hind limbs long ; the 

 tail of moderate length or long, and turned up at the end ; and the fur is very fine and soft. They are 

 Rodents of moderate size and more or less of Rabbit-like appearance, except that the tail is always 

 elongated and bushy. Of the five known species, four are inhabitants of the mountain regions, and 

 one lives in the plains of the region of La Plata. 



The latter, the VISCACHA (Layostomus trichodactylus), is a stout-built and almost Marmot-like 

 creature, from eighteen inches to two feet long, exclusive of the tail, which measures from six to eight 

 inches. It has four toes on the fore limbs, and three on the hind feet, the latter furnished with long, 

 compressed, and pointed nails ; the muffle is broad and covered with a velvet-like coat of brown hair ; 

 the fur, which is soft and moderately long, is of a mottled grey colour above, and white or yellowish- 

 white beneath ; on each cheek there is a dark band ; a white band crosses the muzzle and runs back on 

 each side almost as far as the eye ; the tail is dusky-brown or black. 



The Viscacha lives on the Pampas from Buenos Ayres to the borders of Patagonia, and where it 

 occurs is generally to be found in great numbers, residing in extensive burrows which it digs for itself 

 in the ground, generally in the neighbourhood of copses, and, if possible, near cultivated fields. Each 

 burrow has a great number of passages leading down to several chambers, in which the Viscachas 

 live in family parties to the number of eight or ten. The Burrowing Owl already mentioned as an 

 associate of the Prairie Dogs of North America, is found about the settlements of the Viscachas, 

 living in their burrows, but it is said that the intrusion of these birds immediately drives out the real 

 owners of the dwelling, as the Owls will not observe those rules of cleanliness which are characteristic 

 of their unwilling hosts. Of course the expelled family has to make itself a new residence, and in 

 this way great stretches of country come to be so undermined that they are dangerous to ride over. 

 According to Mr. Darwin, the most favourite resort of the Viscachas in the neighbourhood of Buenos 

 Ayres are those parts of the plain which, during half the year, are covered with great thistles. 



They are nocturnal in their habits, passing the day sleeping in the recesses of their burrows, 

 and coming forth in the twilight one by one, until a large and lively company is to be seen 

 playing about the neighbourhood of their holes. When all is quiet they go in search of their 

 food, which consists of grasses and other herbage and roots, and sometimes of the bark of trees 

 and shrubs. In cultivated fields they may do considerable damage. While engaged in feeding, 

 one or other of the party is perpetually on the watch, and the moment anything occurs to cause 

 alarm, the whole of them scamper away with their tails elevated, to take refuge in their holes. 

 In their movements they are very like Rabbits, but less active. 



The Viscacha has the very singular habit of dragging all sorts of hard objects to the mouth 

 of its burrow, where bones, stones, thistle-stalks, hard lumps of earth, dry cow-dung, and other 

 chance articles may be found collected into a heap, frequently, according to Mr. Darwin, amount- 

 ing to as much as a wheelbarrow would contain. Mr. Darwin says that he was informed that 

 " a gentleman riding on a dark night dropped his watch ; he returned in the morning, and by search- 

 ing in the neighbourhood of every Viscacha hole on the line of road, as he expected, soon found it." 

 The purpose of this accumulation, of apparently useless articles by the Viscacha has never been 

 ascertained. It has been compared to the habit of some of the Australian Bower-birds, which adorn 

 their playing-places with bright and glittering objects. 



The Chinchillas of the Andes, or Alpine Chinchillas, are much lighter and more elegant animals 

 than their cousins of the plains ; in form they more resemble Squirrels or large Dormice. Their fur 

 is excessively soft, perhaps the softest that clothes any animal, and in all the species it is of a grey 



