444 THE MAMMALS 



blooded, have a placenta, nurse their young with mammary glands after 

 birth, breathe by lungs, and have the other typical mammalian charac- 

 teristics. The tail is horizontal, rather than vertical, as in fish. This 

 makes them swim with an up and down rolling motion in contrast to the 

 side-to-side movements of the fish. 



The whales have the distinction of being the largest animals that ever 

 existed. One measured 103 feet long, and weighed the tremendous 

 amount of 294,000 pounds. Whales have a heavy deposit of fat, or blub- 

 ber, under the skin that gives them a good insulation from the cold 

 waters in which they are often found. Unfortunately, for the whales, 

 this blubber furnishes commercially valuable whale oil and so they are 

 hunted by whaling vessels. Also, they may have an extremely valuable 

 substance, ambergris, in the intestine from which the most expensive 

 perfumes are made. Some species have long strainers in their mouths 

 called whale bone, which, in the past, was used extensively as stays in 

 women's corsets, but changing styles in feminine figures and other means 

 of control of body parts that bulge in the wrong places have about 

 eliminated their use in this respect. 



The whales have their single nostril on the top of the head. They 

 may be seen "blowing" at a great distance. This spout, which can be 

 seen coming up from the nostril, is formed of condensing moisture and 

 is not a spout of water. If the outside air is cool, the warm air from the 

 lungs will condense and form a visible water vapor, just as a person's 

 breath condenses on a cold day. 



The porpoises are just a miniature edition of the whales, their struc- 

 ture being about the same. They are an interesting sight following in 

 the wake of boats with their rolling motions, and sometimes they jump 

 entirely out of the water. 



Order — Proboscidea 



The only living members of this order are the elephants, which are 

 the largest of the living land animals. There are two varieties : the Af- 

 rican elephant, which may be eleven and one-half feet tall at the shoul- 

 ders and has huge ears that completely cover its shoulders ; and the In- 

 dian elephant, which may be ten feet high and has smaller ears. In spite 

 of their huge size they are rather easily captured and tamed and become 

 valuable beasts of burden in tropical countries. In some parts of India, 

 travel by elephant is the only way a person can get through a dense 

 jungle. The tusks, which may be more than eleven feet long in the 

 African elephant, are a valuable source of ivory. 



