The fur-seals are sometimes known as sea-bears, although they are not even as much like bears as the sea-lions are like lions. They are destroyed in very great numbers for the sake of their skins, which have a thick coating of soft fur under the stiff outer bristles. These bristles, of course, have to be removed before the fur can be used, and this is done by shaving the inner surface of the skin away until their roots are cut off. They can then be pulled out without any difficulty, while the roots of the under-fur, which are not nearly so deeply buried, are not hurt in the least. But the operation is not at all an easy one, and can only be performed by a highly skilled workman, and that is one reason why sealskin jackets are so expensive. Another reason is that in almost every skin there are a number of flaws, all of which have to be most carefully cut out, after which the holes have to be filled up in such a way as to leave no traces of the operation. Then the fur has to be cleaned, combed, and prepared and dyed, so that the garments which are made from it really cannot be sold except at a very high price. These seals are not hunted in the sea, for they are such good swimmers that it would be very difficult to kill them. So during the greater part of the year they are allowed to live in peace. But during the breeding-season they live on land, lying upon certain parts of the coast in enormous herds; and the seal-hunters visit these places, drive the young males to a distance from the rest, and there kill them by striking them on the head with a heavy club. Such vast numbers of fur-seals were destroyed in this way that at last it became necessary to protect them, for fear lest they should be entirely killed off. So only a certain number may now be killed in each year. The best known of the fur-seals is the northern sea-bear, which is found on both shores of the Northern Pacific. It used to visit the Pribilof Islands in enormous numbers during the breeding-season, but lately so many have been killed, despite protective laws, that now the herds are quite small. THE HOODED SEAL Another seal whose fur is very valuable is called the hooded seal, or crested seal, because the adult male has a singular growth upon the front part of the head. This hood or crest consists of a kind of bag of skin which lies just above the nose, and can be inflated with air at will. What its use may be in a state of nature is not known. But when the seal is hunted it is often of the greatest service, for the force of a blow which would otherwise have caused instant death is so broken by the crest that the animal is merely stunned for a few moments, and is able to slip into the water before the hunter returns to take off its skin.