NATIONAL ZOOLOGICAL PARK HOLLISTER. 559 



merous black or blackish examples. These are descendents of black 

 squirrel stock introduced in the park a number of years ago from 

 southern Ontario. Other members of the squirrel family shown are 

 the Abert's squirrel (Sciurus aberti) from Arizona, the prairie dog 

 {Cynomys ludovicianus) , and various species of ground squirrels 

 and marmots. The prairie dogs have an inclosed area near the eland 

 yards where they live the social village life so characteristic of the 

 species. Numbers of young are born and reared each year. During 

 the coldest winter weather the prairie dogs hibernate, but in nice 

 weather they are always to be seen about the "dog town." 



Two aquatic rodents, the American beaver {Castor canadensis) 

 and the coypu (Myo castor coy pus) of South America enjoy the run- 

 ning stream above the sea lion pool. The beavers have an extensive 

 yard and have dammed the stream in true beaver fashion so that the 

 resulting lake offers them the most natural surroundings. They are 

 best seen in the late afternoon. The coypu, or nutria, is thoroughly at 

 home in the water, and the teats of the female are placed high on the 

 side of the back so that the young are able to nurse without diving. 

 The fur is valuable for many purposes but is chiefly cut and used in 

 the manufacture of hats. As many as 500,000 skins have been ex- 

 ported from South America within a single year. 



The European porcupine (Hystrix cristataz) is a splendid species 

 whose quills are far longer than those of the American porcupines. 



Among the attractive rodents found only in tropical America are 

 the families Caviidee, Dasyproctidse, and Chinchillidse. Many spe- 

 cies are peculiarly adapted to zoological park life, are showy ani- 

 mals, and breed regularly in captivity. The guinea pig (Cavia por- 

 cellus), so familiar to children, is bred in large numbers. The wild 

 guinea pig of Peru, a grayish species, is also on exhibition. A larger 

 species, the Patagonian cavy (Dolickotis patagonica), a peculiar 

 rough-haired animal with something the appearance of a big rabbit, 

 is shown in the antelope house. The paca ( Cunaevlus paca) , one of 

 the larger rodents, has a brown body well marked with whitish 

 spots. He is related to the agouti (Dasyprocta) of which a num- 

 ber of species are regularly kept. Some of the species of agouti 

 are brilliantly marked ; a most striking species is the hairy-rumped 

 agouti (Z>. prymnolopha) . Agoutis range north into Mexico and on 

 several of the West Indian Islands. They are hunted with dogs by 

 the natives, and are said to be almost as cunning as a fox. The 

 viscacha (Lagostomm maximm) is related to the famous chinchilla. 

 It has some of the habits of the prairie dog and lives in villages in 

 open country, but the towns do not approach in size those of the 

 North American animal. 



The mountain beaver, or sewellel (Aplodontia rufa) is a peculiar 

 burrowing rodent of the Pacific coast region of North America. It 



