The animals that tempted the tireless and fearless sons particularly of France, England, Scotland, and Russia to build their fortified trading-posts throughout the subarctic forest from the St. Lawrence to the Mackenzie and Yukon, were principally the beaver, sable, ermine, fox, mink, wolverene, bear, otter, wolf, lynx, musk-rat, skunk, marmot, etc. Nearly all of these animals are forest dwellers, and several of them, as the beaver, otter, mink, and musk-rat, haunt the shores of streams and lakes. Of the sable, there are two species, known as the marten and the fisher. The bears are represented by at least four species. The foxes number at least a dozen species, of which four are especially prized for the beauty of their fur, namely, the arctic, red, cross, and silver. While the fur-bearing animals named above are characteristic of the life of the boreal region of North America, a number of the species, and, in fact, nearly all of them, range southward into the austral region, especially in the more humid and generally forest-covered portions of both the Pacific and Atlantic mountains, while one of the most important as regards the beauty of its fur--the otter (_Lutra canadensis_), frequently termed the land-otter, in order not to confound it with its larger and far more valuable cousin, the sea-otter (_Enhydra marina_)--reaches the torrid region and is still living in Florida, and has been reported as occurring in Central America. Of all the fur-bearing animals referred to above, the most valuable when the total number of skins that have been taken is considered, and in many ways the most interesting, is the beaver, of which but one living species (_Castor canadensis_), closely allied to the beaver of northern Europe, is known in America. Fully grown individuals are about 3 feet in length, one-third of which is to be credited to the broad, flat, scale-covered tail, and weighs some 50 or 60 pounds. The outer coat of its pelage consists of rather coarse brown hair, beneath which there is a fine, soft, dark fur, which makes its skin of commercial value. In dressing the skins the hair is plucked, the fine fur beneath being clipped to a uniform length and usually dyed. The formerly well-known beaver hat was made from this fur, but in recent years silk has taken its place. The importance of the American beaver is illustrated by the fact that some 7,000,000 skins have been sold in London by the Hudson's Bay Company since the year 1752. Not only is the fur of the beaver in demand, but its flesh, and especially the muscles of the tail, are prized for food by hunters and others who live the free, open-air life of the frontier, although it is seldom exposed for sale in the markets of cities.