MAMMALIA 



349 



head low. From the chin, throat, and lower parts of the sides the hair 

 grows long and forms a fringe, a wonderful adaptation to the climate. This 

 long hair serves as a mat beneath it when it lies down upon the ice and snow, 

 as well as a warm cover under which it curls its legs. The tail is thick and 

 silky, sometimes 6 feet long. It is often beautifully mounted on antelope- 

 horn handles and used for fly-whisks in the East. The cry is much like the 

 grunt of a pig, but louder and longer. ' Tame yaks have long been used as 

 strong, sure-footed beasts of burden. The flesh, milk, and butter are ex- 

 cellent. From its hide, clothing, tent covers, and harness are made, and the 

 hair is twisted into ropes. 



Fig. 283. — A group of bufTaloes, " American bison " (Bos americanus) in 

 Yellowstone National Park. (From life.) 



The numerous breeds of domestic cattle form an enormous industry. 

 The exports of the United States alone, such as cheese, butter, hides, tallow, 

 and beef, amount to many million dollars annually. 



Geologic Distribution of Ungulates. — The camel is represented 

 in the Ohgocene. The Miocene forms in America had horns 

 something hke deer antlers. The Procamelus, the probable 

 ancestor of both camels and llamas, flourished in the Miocene. 

 In the Pliocene, Europe had deer, antelopes, oxen, and the first 

 1 Ingersoll, p. 247. 



