212 



ANIMAL BIOLOGY 



FIG. 384. TAPIR OF SOUTH AMERICA ( Tapirus americanus). X jt. 

 Questions: How does it resemble an elephant? (Fig. 376.) A horse ? (p. 210.) 



Ungulates, as the horse, need no other protection than 

 their great speed, which is due to lengthening the bones of 



the legs and rising 

 upon the very tip of 

 the largest toe, which, 

 to support the weight, 

 developed an enor- 

 mous toe-nail called a 

 hoof. The cattle, not 

 having developed such 

 speed as the horse, 

 usually have horns 

 for defense. If a calf 

 or cow bellows with distress, all the cattle in the neigh- 

 borhood rush to the rescue. This unselfish instinct to 

 help others was an aid to the survival of wild cattle living 

 in regions infested with beasts of prey. Which of yEsop's 

 fables is based upon this instinct? The habit of rapid 

 grazing and the correlated habit of chewing the cud were 

 also of great value, as it enabled cattle to obtain grass hur- 



FlG. 385. HORSE, descended from a small 

 wild species still found in Western Asia. 



