82 MOUNTAIN FAUNAS 



described the way in which the animals push their way 

 through snow, or across glaciers, or through icy glacial 

 torrents. They present a remarkable instance of 

 adaptation to very unfavourable conditions, but in this 

 connexion it is important to remember the great extent 

 of the plateau of Tibet, and its great uniformity. 



The yak is the only member of the cattle group with 

 special adaptations to moimtain life. Passing to the 

 sheep we find that there are eleven well-defined wild 

 species. Of these, eight inhabit various mountain chains 

 and plateaux in Asia, one, the Indian urial, extending 

 to relatively low ground in the Punjab and Sind ; one 

 form is found in the Rocky Mountains, but this, the 

 Bighorn, is so closely related to the wild sheep of 

 Kamchatka as to suggest a former land connexion 

 across the Bering Strait. Of the remaining two species, 

 one, the mouflon, occurs in moimtain regions in Sardinia 

 and Corsica, and the other, the Barbary sheep, is foimd 

 on the southern slopes of the Atlas Motmtains in Africa. 

 We are thus justified not only in saying that sheep are 

 definitely mountain animals, but also that the home of 

 the genus is the mountainous regions of Central Asia, 

 only the urial extending south of the Himalayas. The 

 habits of all are generally similar, and have been 

 already alluded to. To the preceding description we 

 may add a brief note on the wild sheep called argali, of 

 which one form {Ovis ammon) is found at moderate 

 elevations in MongoHa, while the other [Ovis hodgsoni) 

 occurs at great heights on the Tibetan plateau. Both 

 are large animals, reaching the size of a small donkey, 

 and having short and close hair. The food consists of 

 grass, mingled in winter with mosses and lichens, and, 

 Mke the reindeer of the tundra, the animals in winter 

 seek exposed positions where the wind sweeps away 



