英文科學(xué)讀本 第六冊(cè)·Lesson 58 The Whale and its Products

Lesson 58 The Whale and its Products

The cetaceans, or whale-like animals, which include the whale itself, the porpoise, the dolphin, the dugong, and the manatee, although they live entirely in the water, are all mammals. They bring forth their young alive, and suckle them just as the land mammals do; they are lung-breathing animals, and their blood is warm.

Nature, as we have seen, provides her various creatures with some sort of coat to prevent this bodily heat from being too rapidly dissipated, and modifies that covering to suit the requirements of each animal. The fur-animals of the frozen regions of the world are a striking example of this beneficent provision; some of them, such as the white bear, the otter, and the seals, which spend much of their lives in the icy water, have especially thick warm furs.

The animals we are about to consider now, however, never leave the water, and they are provided for in a different way; a thick coat of fur would not do in their case. Their skin is bare and naked on the outside, but immediately beneath it (in fact, forming part of it) is a thick under-coat of fat. Fat is a bad conductor of heat, so that the under-coat of fat performs the same office for these creatures as the thick fur covering does for the land mammals. It keeps their blood warm in those icy seas. But it does more than this; for being lighter than the water, it helps to keep the animals afloat.

It varies from 8 inches to 20 inches in thickness, according to the habitat of the animal. In the right whale of the frozen Arctic seas it is thickest, and is known as blubber; in the South Sea whale it is comparatively thin. The seals, because they live partly in the water, have a thin layer of this oily fat under their fur coat.

There are two kinds of whales—the baleen whale, which has no teeth, and the sperm whale, which has formidable teeth or tusks in the lower jaw.

The former class includes the Greenland, or right whale of the North Polar Seas; the South Sea or black whale of the Southern Ocean, especially round the Australian coasts and the extremities of Africa and America; and the Pacific or American whale of the north coast of America, round the neighborhood of Behring's Straits. These whales are all very different in shape and size; the most valuable is the Greenland whale, an enormous creature, the largest of all the animals in the world, sometimes reaching 80 feet in length.

These whales have no teeth, but they have, hanging down from the upper jaw, on each side of the tongue, an extensive row of about 300 flat plates or blades of baleen or whalebone. These baleen plates are at right angles to the jawbone, and hang parallel to each other. They form, as they hang from the roof of the mouth, a transverse arch, the inner edge of each plate being fringed with stiff but flexible hairs. When the mouth is shut the fringed edges of the baleen plates rest on the upper convex surface of the tongue.

The largest of the baleen plates springs from the middle or highest part of the roof. These are sometimes from 12 to 15 feet in length; each plate is usually from 10 to 12 inches wide at the root, and about half an inch thick. The plates diminish in size as they near the front of the mouth, those in the front being only a few inches long. One of the largest plates usually weighs 7 lbs., and the total yield of whalebone from a large whale is about one ton.

The baleen whales, having no teeth, are unable to kill and devour other large inhabitants of the sea, in spite of their own enormous size. Their throat is so small that it would be impossible for them to swallow any creature larger than a herring. Their food, in fact, consists of very small animals—for the most part the small soft-bodied animals which exist in myriads in every sea.

Think of the enormous number of such small things it must take to supply one meal, and then think of the manner in which it captures them. Picture to yourselves this powerful creature cleaving its way with headlong speed through the water, with its immense cavernous mouth wide open. This mouth, with its fringed baleen plates, is a trap to catch thousands and thousands of the small prey as the whale rushes through the water.

The baleen whales are hunted and killed for the sake of their blubber and baleen plates.

Whalebone was till late years largely used for the ribs or stretchers of umbrellas. Nowadays steel frames are mostly used, but whalebone is still employed for the best carriage umbrellas. It is also much used, split into fibers, as a substitute for bristles for coarse brooms and brushes. It is used in thin narrow slips to strengthen women's stays and corsets. Whalebone softens when heated, and becomes pliable. In this state it is molded into a variety of articles, such as knobs for walking-sticks, whip-handles, etc.

When a whale is caught the blubber is all removed from the carcass for the sake of the oil which it contains. The blubber of a full-grown whale will yield 100 tons of oil. It is known in commerce as train-oil or whale-oil.

The sperm whale or cachalot of the Eastern Archipelago (that is the seas between Australia and Japan) is a very different animal from the baleen whale. It is sought after mostly for the sake of a very valuable oil—spermaceti— which is obtained from the head. The oil obtained from the carcass itself is known as sperm oil.

The head is of enormous size—half as large as the entire body, and is said to weigh 35 tons. It has formidable teeth in the lower jaw, but no baleen plates. The teeth are from twenty to twenty-five in number, and vary in size, some of them weighing as much as 30 lbs. The oily matter of the head is contained in a triangular-shaped hollow, which is known as the sperm case. About 400 gallons of oil are usually obtained from a single head.

This enormous mass of oil makes the head very light, and, in fact, acts as a kind of float to keep the nostrils above the water.

Spermaceti is used mostly for making candles, but its use for this and other purposes has greatly diminished during the last quarter of a century. The introduction of petroleum and vegetable oils has had the effect of driving this and other animal oils out of the market. The consequence is that the whale fisheries have gradually declined, both as regards British and foreign ports, while France has given them up altogether.