As the Whale forces used-up air from its nostril--or "blow-hole," as it is called--it mixes with water; this causes a jet or spout of water to rise some distance into the air. The blow-hole is closed by a stopper or valve, opening to let the air in or out, but closing to shut out the water. Some of the Whale family are enormous, and some are small. A large Sperm Whale may grow to be ninety feet long, and its weight would be nearly two hundred tons! This huge creature would look like a deep barge in the water. These Sperm Whales love to swim in herds, or schools. As many as three hundred have been seen in one school, old "bulls" and "cows," and their young ones swimming together far out at sea. It has been noticed that they all spout, or breathe, at the same time, and then dive to great depths. The old ones seem to know that their babies cannot stay under water as long as a full-grown Whale can, and they all rise at the same time. These youngsters may be nearly thirty feet long; but they gambol like so many kittens, twisting and turning over and over, and throwing themselves into the air. Most Whales are happy creatures, enjoying their roving life in the free ocean. You can well imagine that a Whale as big as a barge needs huge dinners. We should not be far wrong if we guessed that he would need about a ton of food every day. Where is he to get all that food? It is said that he feeds mostly on the Cuttle-fish, that giant cousin of the Octopus, who haunts the dim caverns of the deep. The Sperm is of enormous strength, and is as fierce as he is strong. Otherwise he would not dare to face the awful, clinging arms of the Cuttle, that ogre of the deep sea. The Sperm Whale has a great, blunt head, a huge mouth, and a throat large enough to swallow a man. His clumsy-looking head contains oil, so does the deep layer of blubber with which his body is covered. For the sake of this oil, the Sperm has always been hunted. But he is not easily overcome. He fights hard for life; and many a whaling boat has been dashed to pieces with one blow from the powerful tail of a hunted Sperm. This great tail is set cross-wise, not upright like the tail of a fish. It is of immense power, and divided into two big "flukes," as they are called. With strong up-and-down strokes the tail propels the monster along at a great pace. It also shoots him down to his feeding place in the depths of the sea, and up again to fill his lungs with sweet fresh air. The fins, or paddles, are used only as balancers, and to protect the young. These Sperm Whales inhabit warm seas, but others of the Whale family haunt colder regions. The greatest of these is the Right Whale, or Greenland Whale, a monster whose bulk rivals that of the Sperm.