How strange now to turn from this ravenous hunter to the huge Sperm Whale, eighty feet long, with a head one-third the size of its whole body and more than a ton of spermacetic oil in its forehead, and to think that this monster swims quietly along in the sea, drops its long thin lower jaw, and with wide-open mouth simply gulps in jelly-fish, small fish, and other fry, thus without any exertion or fuss slaying its millions of small and soft creatures quietly, as the orca does the higher creatures with so much battle and strife! For the sperm whale (Fig. 87) must need a great deal of food to feed its huge body. Though it has forty-two teeth in the lower jaw it never cuts those in the upper one, and seems to depend more on sweeping its prey into its mouth than on attacking it. And this perhaps partly explains the use of that curious case of spermaceti which lies in its huge forehead over the tough fat of its upper jaw. For this oil gives out a powerful scent, which, when the whale is feeding below in the deep water, most probably attracts fish and other small animals, as they are also certainly attracted nearer the surface by the shining white lining of its mouth. This light mass is also, however, useful in giving the head a tendency to rise, so that when the whale wishes to swim quickly it has only to rise to the top, so that the bulk of its head will stand out of the water, the lower and narrow part cutting the waves. In this position he can go at the rate of twelve to twenty miles an hour. But if the sperm whale is curious, as it carries its oil-laden head through all seas from pole to pole, chiefly in warmer latitudes, how much more so are the whalebone whales, which are monarchs of the colder and arctic seas, where they feed on the swarms of mollusca, crustaceans, and jelly animals which live there. For these large whales, though they have teeth in their gums, never cut them, but in their place they have large sheets of whalebone hanging down from the upper jaw (see Fig. 84), smooth on the outside, fringed with short hairs on the inside, and crowded together so thickly, only about a quarter of an inch apart, that as many as three hundred sheets hang down on each side of the mouth of the great Greenland whale. [Illustration: Fig. 87. The Sperm Whale.] It is easy to see the use of these whalebones when we remember that this huge whale feeds entirely by filling its enormous mouth with water, and then closing it and raising its thick tongue at the back so as to drive the water out at the sides, straining it through the fine fringes, which fill up all the spaces between the plates and keep back every little shell-fish and soft animal. But it is less easy to guess where these whalebone plates come from, till we look back at the manatee, and remember those horny ridges which it uses for biting, and which are exaggerations of the rough fleshy ridges at the top of a cow’s mouth.