英文科學(xué)讀本 第五冊(cè)·Lesson 54 Coverings of Mammals—Furs

Lesson 54 Coverings of Mammals—Furs

In the coats of some mammals the hairs are very fine, soft, and smooth, and grow thick and close on the skin. Such a covering is called fur. The fur animals belong mostly to the colder regions of the earth—some of them to the extreme frozen north. Nature has thus provided the very coat that is best suited to such a climate.

Our lessons on heat showed us that fur is a non-conductor; it protects these animals from the rigor of the climate by preventing their bodily heat from passing away. All these creatures, like the rabbit and our domestic cat, partly shed their fur in the summer, so that during the hot weather their coat is loose and open. With the return of winter the fur coat is renewed as thick and close as ever.

Another very remarkable fact should be noticed in connection with these fur animals. Some of them, such as the foxes of the Arctic regions, some hares, and the ermine or stoat of our cold countries, actually change the color of their fur at the approach of winter. After a few days' exposure to the snow the fur becomes white, not because new white hairs have grown, but because every existing hair has changed color.

Let us once again carry our minds back to our lessons on heat. In one of those lessons we learned that white and light-colored substances generally are bad radiators of heat. These white fur coats do not radiate the bodily heat so quickly as darker-colored fur would.

This, again, is only one part of Nature's beneficent provision. The whiteness of the fur is so like the snowy surroundings as to afford these creatures a sort of protection against their numerous prowling enemies. They cannot be easily seen against the white snow all round them.

If the coat of a fur animal be carefully examined, it will be seen that the fur is not all alike. There is a thick, short, close, silky fur near the skin, and other long, stiff, straight hairs overlying it. The former is the real fur; the latter is known as the over-hair. This over-hair performs an important duty in helping to keep the fur somewhat loose, and so preventing it from matting together.

The furs of animals furnish us with one of the richest, warmest, and most beautiful materials for our own clothing. Many millions of animals are killed every year for the sake of their fur-skins, or pelts, as they are called.

It is clear, from what has already been said, that the best time for taking these animals is the winter, for then their coats are at their thickest and best.

A considerable number of the skins are dried and dressed for use with the fur on them. It is estimated that for this purpose alone no fewer than thirty million pelts are collected every year.

Among the furs used are those of the squirrel, sable, hare, rabbit, ermine (the white winter dress of the stoat), pole-cat, black-fox, silver-fox, red-fox, blue-fox, beaver, seal, sea-otter, minx, bear, skunk, marten, and racoon.

Many of these owe their elegance and value chiefly to the length and fineness of the over-hair; but in the preparation of the seal-skin the over-hair is all cut away.

This is done in a curious way. The skin is stretched out flat with the flesh side uppermost, and part of the skin is pared or shaved off with a sharp, flat knife. In cutting away this under surface of the skin, the deeply-embedded roots of the over-hairs are cut through, and it is an easy matter then to pull out the hairs.

Immense numbers, amounting to many millions, of hare and rabbit skins are used every year in the manufacture of felt for felt hats. For this purpose the fur only is used. It is first separated from the skin, and then by means of hot water and pressure the hairs are made to interlace and mat themselves together so as to form a hard felt.