66 MANAGEMENT AND BREEDING OF HORSES 



petition with the bison" and the antelope, which had recently 

 migrated to America, may have made it more difficult 

 than formerly for the horse to get a living. Probably 

 primitive men in the hunt played a large part in ex- 

 tinguishing the race. Some unknown disease or pro- 

 longed season of drouth may have aided in the extermina- 

 tion. 



Ancestors of modern horse. — The connecting link be- 

 tween the prehistoric horse and the modern horse is not 

 definitely known, but is assumed to be the present form 

 of zebra, the Asiatic and African wild ass, and Przewal- 

 sky horse. The latter was discovered on the desert of 

 Zungaria in western Mongolia in Asia by Poliakofif, in 

 1881. This animal stood about 40 inches high and is as- 

 sumed to be similar in type to the horse as known by 

 primitive man. The drawings left by the European cave 

 dwellers show a strong resemblance to this type, and it is 

 probable that from such an ancestor have come the ponies 

 of northern Europe as well as of Mongolia and China. 



