As a general rule a whale spends from ten to twelve minutes in spouting, and can then remain under water, if necessary, for considerably more than an hour. It is owing to this singular method of breathing that whales can be so easily killed. The object of the hunters is simply to drive them below before they have finished spouting. They do this again and again, and the consequence is that the poor animal soon becomes completely exhausted and falls an easy prey. THE WHALE'S BLUBBER You remember, don't you, how the seals are protected from cold, partly by their thick and oily fur, and partly by the layer of fat which lies just under the skin? Well, the whales are protected in much the same way. They have no fur, of course; but the layer of fat, which we call blubber, is always several inches in thickness, and is sometimes as much as two feet; so that the whale is never chilled by living in the water, even when it has to make its way through floating ice. This blubber has another use as well. When the whale dives to a great depth--and sometimes it sinks half a mile or more beneath the surface of the sea--the pressure on its body becomes enormously great because of the weight of the water above it. If you were to dive to half that depth you would die. But the blubber of the whale is so elastic that it resists the pressure just as a great thick sheet of india-rubber would, so that the animal does not suffer from it in the least. MISTAKES OF ARTISTS Sometimes you see pictures in which whales are drawn with very big eyes, very long ears, and perhaps even with their tongues hanging out of their mouths. Now such pictures are drawn by artists who know nothing about whales, for the eyes of these animals are quite small, their outward ears are merely little holes in the skin, closing by means of self-acting valves like those of the seals, and the tongue cannot be poked out of the mouth at all. Now let us learn something about the different kinds of whales. TOOTHED WHALES First come the toothed whales, or denticetes. As an example of these we will take the famous sperm or spermaceti whale, which is also known as the cachalot. This whale has nearly all its teeth in the lower jaw, the upper one only having a very short row of small teeth on either side. The lower teeth are five or six inches long, and fit into pits in the upper jaw when the mouth is closed. These teeth are composed of beautiful ivory, and were formerly valued so highly by the natives of the South Sea Islands, that more than once a tribe has actually gone to war with another tribe simply to obtain possession of a single whale's tooth.