Page:First course in biology (IA firstcourseinbio00bailrich).pdf/450

 (Tapirus americanus). × 1/25.

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

, descended from a small wild species still found in Western Asia.

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 enormous 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 neighborhood 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 Æsop'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-