Now it is very strange that this, the largest member of the whole kingdom of animals, should live on some of the smallest creatures of the sea, and that the mouth and throat of this monster should be so made that he can eat only this minute food, food like that which the tiny Herring eats. In some parts of those cold northern seas the water is coloured in bands of red and blue. If you took up a bucketful, you would find that the colour was due to myriads of tiny creatures. Amongst these are other myriads of small animals, each of less size than a house-fly. The larger ones are there to feed on the smaller ones. And that mass of small life is the food of this mountain of fat and flesh, the Greenland Whale. He swims through the sea with his mouth gaping open, like a great cavern, and soon thousands of the little creatures are inside. Then his tongue comes forward. It is of immense size, and it pushes out all the sea water from his mouth. But the small animals remain inside! For the water is forced through a wonderful sieve, made of fringed plates, which hangs from his upper jaw. Instead of having teeth in his mouth, as many Whales have, the Greenland Whale has this sieve of "whalebone." Of course it is a large sieve, to fill so large a mouth. Yet it is never in the way, being neatly packed away at the top of the mouth, one plate over the other, when not in use. The mass of small animals, held back by this peculiar sieve, then slides down his throat, which is a tube about as wide as a boy's wrist! We said just now that Nature was full of surprises. Is it not surprising to find a gigantic Whale feeding in this way! Inside the great mouth the _Remora_? or Sucking Fish, is often found. This fish has an oval sucker on its head, by which it fixes itself to Whales, or even to the hull of a ship. It has fins, and can swim perfectly well, but prefers to live in this lazy way. The Whalebone Whales lead a peaceful, happy life, though not without dangers. The bitter cold of their northern home is nothing to them, for are they not snug in a deep blanket of blubber? To obtain food, they merely swim along with open mouth. These peaceful giants do not know how to fight for their lives, like the Sperm Whales. So, when man came, hunting the Greenland Whale for oil and "whalebone," he found an easy victim. They have other enemies, besides man. The Killer Whale is one of the fiercest, swiftest terrors of the sea. It is tiny, compared with the Greenland Whale, but much quicker and more cunning. Several Killers band together and spring to the attack at the same time, Like wild cats, they dash at the poor helpless Whale, and tear its sides with terrible curved teeth.