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.
Then we have a clue, for each blade of whalebone grows from a horny white gum, being fed by a fleshy substance below much in the same way as our nails are, so that these blades are, as it were, a series of hardened ridges, which grow out from the soft palate, till they become frayed at the edges, and form that dense fringe which is the whale’s strainer, upon which he depends entirely for his food.
Explain it as we will, however, it is a most wonderful apparatus. Imagine a huge upper jaw forming an arch more than nine feet high, so that if the whalebone were cleared away a man could walk about inside, upon the thick tongue which lies in the lower jaw fastened down almost to the tip so that it cannot be put out of the mouth. And then remember that this enormous mouth has to be filled with food sufficient to nourish a body fifty or more feet long. Who would ever guess that this food is made up of creatures so small that countless millions must go to a mouthful? Yet the whole difficulty is solved simply by these triangular fringed plates or mouth-ridges (see section [Fig. 84], [p. 318]), covered with horny matter and frayed into minute threads like the horny barbs of a feather.
Nor are we yet at the end of the wonderful adaptation, for while the jaw is only from nine to twelve feet high, the long outside edge of the plates is often eighteen feet long, and for this reason, that if they were only as long as the jaw is deep, then when the whale went fishing with his mouth open the animals would escape below the fringe, while as they now are, he may gape as wide as he will, the long curtain will still guard the passage of the mouth and entangle the prey in its meshes. But what, then, is to become of this great length of whalebone when the animal shuts his mouth? Here comes in the use of the beautiful elasticity of the plates, for the great Arctic whaler, Captain Gray, has shown that as the mouth shuts the lower ends of the longer plates bend back towards the throat and fall into the hollow formed by the short blades behind them, so that the whole lies compactly fitted in, ready to spring open again, and fill the gap whenever the jaws are distended.
With this magnificent fishing-net the whalebone whales go a-fishing in all the salt waters of the world. They are not all of enormous size,—many of them are not more than twenty feet long,—nor have they all such a perfect mouthful of whalebone as the great Polar Whale; but when the whalebone is shorter, as in the Rorqual, and other whales with back fins, the stiff walls of the lower lip close in the sides of the mouth and prevent the escape of the prey; and many of these whales have a curious arrangement of skin folds under the lower jaw, which stretch out and enable them to take in enormous mouthfuls of water, so as to secure more food.
New Zealand, California, Japan, the Cape, the Bay of Biscay, and in fact almost every shore or sea from pole to pole, has some whale called by its name; for these gaping fishers are everywhere, and it is not always easy to say whether the same whale is not called by different names in various parts of the world. In the shallow bays and lagoons they may be found with their newly-born young ones very early in the year; while far out at sea ships meet with them travelling in shoals, or “schools,” northwards, as the summer sets in and the Arctic Sea is swarming with life. In fact the Californian gray whales go right up into the ice, poking their noses up through the holes to breathe, and then they travel far away south again into the tropics to bring up their young ones.
And whether large or small, toothed whales or whalebone whales, active as the dolphin and the huge fin-whales or rorquals, which dash through the water although some are nearly a hundred feet long, or lazy and harmless as the Greenland whale is unless attacked, in one thing all the whale family betray their high place in the animal kingdom. Nowhere, either on land or in the water, can mothers be found more tender, more devoted, or more willing to sacrifice their lives for their children than whale-mothers. Scoresby tells us that the whalers, as means of catching the grown-up whales, will sometimes strike a young one with harpoon and line, sure that the mother will come to its rescue. Then she may be seen coming to the top with it encouraging it to swim away, and she will even take it under her fin, and, in spite of the harpoons of the whalers, will never leave it till life is extinct. Nay, she has been known to carry it off triumphantly, for the lash of her tail is furiously strong when she is maddened by the danger of her child, so that a boat’s crew scarcely dare approach her.
And now there remains the question what enemies besides man these strong-swimming milk-givers can have in their ocean home? We have seen that the orca or killer whale will turn cannibal and devour those of its own kind, and the swordfish is said to attack whales with its formidable spear; but these are not their greatest enemies. With many of the whales it is tiny creatures like those on which they feed which hasten their death, for small parasitic crustaceans cover their head and fins, and feed upon their fat, so that whales which have been infested with these animals are often found to be “dry,” or to have lost nearly all their oil. And thus we see the tables turned, and while the whale feeds upon minute creatures, it is in its turn destroyed by them.