94 TEXT-BOOK OF ZOOLOGY 



A. The Boar as an Inhabitant of the Forest. 



The wild boar, like the elephant (which see), is capable of forcing its way 

 through the thickets and undergrowth of the forest. It is equipped for this 

 purpose with 



1. A conical head, which it pushes like a wedge through the bushes. 

 Through the opening thus formed it next advances its rigid, laterally 

 compressed body, which forms a second and still larger wedge. In this 

 manner, with "lightning speed," as we are informed by a careful 

 observer, the animal rushes through thickets quite impenetrable by any 

 other creature. 



2. By means of the short, powerful legs and the two middle toes, 

 which are encased in strong hoofs, the animal is enabled to obtain a 

 firm purchase against the ground. (Would an animal with long legs 

 and hoofless toes be able to do this ?) The two other toes are shorter 

 and weaker, and do not touch the ground. 



3. The skin is very tough, as a protection against injuries which 

 might be sustained while breaking through the thicket (compare the 

 so-called " rind of bacon " from the domestic pig). 



4. The coating of bristles which covers the skin becomes also 

 intelligible in relation to this habit of the animal of breaking through 

 thickets. (Could you imagine a sheep, for instance, forcing its way 

 through dense underwood ?) 



5. The small, strong eyes are deep-set, and surrounded by dense 

 growths of bristles. 



6. The thicket of the forest affords these animals, and more especially 

 their still defenceless young, a safe protection against their enemies. 



B. The Boar as an Inhabitant of the Marsh. 



Water is one of the necessary conditions of the life of this animal. 

 It evidently delights to wallow in swamps. 



1. How is it prevented from Sinking ? (a) By the separation of the 

 broad central toes, the area of the surface of support is increased (compare 

 with camel). This happens even on hard ground, but still more on mud, 

 because the latter penetrates between the toes. When these toes sink in 

 further, the smaller hind toes reach the ground, and give further support. 



(b) By again bringing the toes together into their normal position, 

 the animal, on sinking in a swamp, soon manages to liberate its feet. 

 For a man this is a much more difficult performance, for on raising the 

 foot a vacuum is formed below its surface. The two-toed ox can also 

 walk on swampy meadows, but not the one-toed horse. 



2. Why weltering in Swamps for Hours does not induce an Excessive 

 Cooling oj the Body. (a) Under the skin is a thick layer of fat (the 



