Let us look at a whale. Its body is cone-shaped; the head is very large, sometimes one-third of the animal’s entire length; there is no notch of the body to mark the neck;[79] the body tapers to the tail, which is widely expanded on each side into what are called flukes, and thus becomes a very strong propeller. Just behind the head we find a pair of fore limbs, called paddles or flippers. These are flat and oval, and have externally no marks of joints, fingers, or nails. But if you examine the skeleton of a whale, you will find that this limb is divided into arm and hand bones, very much like those of your own arms and fingers. There are no external signs of hind limbs, but in some kinds of whales we find in the skeletons some small, soft bones like a hint of legs. The skin of the whale is smooth, of a dark gray or black color, and without hair except a few bristles around the mouth. Under the skin is spread a layer of several inches of fat, called blubber. This layer of blubber serves to keep the whale warm, and also to render its huge body light, so that it will float easily; it also keeps it from being readily injured. Most whales have a low, narrow fin down the centre of the back, to aid them in keeping a proper position in the water. Let us now examine more particularly the whale’s big head; it has small eyes, and a pair of tiny holes for ears. These ears are close behind the eyes, but the nostrils are usually placed on top of the head. In nearly all varieties of whales we find teeth inside the large mouth. In one very important species there are no teeth, but instead, we find a large number of horny plates. The whale’s mouth opens very wide, and the lips are stiff and immovable, not soft and flexible like our own. Most people have read of the _blowing_ or spouting of the whale, when it sends a double stream of water from its nostrils up into the air. The general idea is that the whale takes this water in at the mouth, and then spurts it up into the air through the nostrils, as a matter of amusement. This is not true. When a whale comes to the surface he takes in a large amount of air, and returns below; most of this air becomes changed to steam or vapor, as the animal remains below for some time. Then the whale comes up for more air, and the first thing is to free his lungs of the heated, vaporized air that is already in them. The animal drives this air violently from its lungs through the nostrils, and rising into the cold atmosphere it is at once changed to spray by condensation. The whale frequently begins to blow before it reaches the top of the water, and so drives surface-water up with the vapor which it expels from its lungs.