of the family Castoridæ, remarkable for its constructive habits, and yielding a valuable fur and the substance castoreum. The family includes only one species, in the opinion of the majority of naturalists, which is, or has been, distributed throughout most of the forested parts of the North Temperate Zone. To this species Linnæus gave the name Castor fiber, and the American form has been regarded as merely a variety of it. Recent American specialists, like Rhoads (Proc. Am. Philos. Soc., 1898), believe, nevertheless, that the American beaver is specifically different from that of the Old World, is entitled to the name Castor Canadensis, and is divisible into three distinct local races. In general characteristics all beavers agree so closely, however, that these niceties of classification may be left to the taxonomists.
The Old World Beaver, once widely common throughout Europe and Northern Asia, is now rare and isolated. Extinct in the British Isles since the Twelfth Century, a few colonies are preserved in the parks of the Marquis of Bute and other noblemen. It is said to exist in southeastern Norway, and isolated, pairs are occasionally seen on some of the large German rivers, and in Austria, under protection of great landowners, “They also occur sparingly in Russia and Poland, in the streams of the Ural Mountains, and in those which flow into the Caspian. They live in burrows on the banks of rivers, like the water-rat, and show little of the architectural instinct so conspicuous in the American form; but this may be owing to unfavorable external conditions rather than to want of the faculty, for there is a well-authenticated instance of a colony of beavers, on a small stream near Magdeburg, whose habitations and dam were exactly similar to those found in America.” In Siberia they still exist in considerable numbers, though their pelts do not now figure largely in the export of furs, and there the animal is inclined to erect lodges and dams.
The American Beaver was scattered primitively over all wooded North America, from Mexico to Labrador and the northwestern limit of tree-growth. It has been banished from all the more thickly settled parts, but survives in greater or less numbers throughout Canada north of civilized Ontario and Quebec, in the Rocky Mountain and Californian ranges, in the Appalachians south of West Virginia, and along the borders of northwestern Mexico. It is steadily decreasing, however, even in the Hudson Bay region. The beaver is usually at least 2 feet in length from the nose to the root of the tail, and weighs about 35 pounds, and the tail is about 10 inches in length. These dimensions are sometimes exceeded. The general form of the animal is thick and clumsy, broadest at the hips and squirrel-like. The body terminates in a thick oval tail, flattened transversely, about twice as long as broad, and naked of hairs, the surface being covered with plates of black, indurated skin, resembling horn-scales. The fore limbs are small and squirrel-like, the hinder ones large and powerful. Each foot has 5 toes; those of the fore-feet are short, and not connected by a web; those of the hind feet are long, spreading out like the toes of a goose, and webbed to the nails. In accordance with this remarkable peculiarity, the beaver in swimming makes use of the hind feet alone, the fore-feet remaining motionless and close to the body. The tail is of service as a sculling-oar and a rudder, and its loud slapping of the water when an alarmed animal dives is an effective signal of danger to others. The head is thick and broad, the nose obtuse, the eyes small, the ears short and rounded. The incisor or cutting teeth (two in each jaw) exhibit in the highest perfection this cardinal characteristic of the Rodentia. They are formed in front of hard, orange-colored enamel, while the back of the tooth is formed of a softer substance, more easily worn down, so that a sharp, chisel-like edge is always preserved; the bulbs being also persistent, so that the teeth are continually growing as they are worn away. There are four flat molar teeth (or grinders) on each side in each jaw.
SKULL OF A BEAVER.
Showing the chisel-like incisors.
The fur consists of two kinds, the longer hair comparatively coarse, smooth, and glossy; the under coat dense, soft, and silky. The color is generally chestnut, rarely black, spotted, or nearly white. The largest and reddest beavers are those dwelling on the streams of the northern Pacific Coast, the smallest and darkest those of the Hudson Bay region, while those inhabiting the southern Alleghanies are reddish brown, and those of the southern Rockies are pale. In consequence of its aquatic and bark-eating habits, the beaver is limited to the neighborhood of streams and ponds in wooded districts, and the northern range of the species is everywhere terminated by the limits of the forest growth. Its extraordinary powers of gnawing are exerted to cut down trees several inches in diameter, both for food and for the construction of those houses and dams which have rendered it so much an object of admiration to mankind. Dr. Elliott Coues mentions a poplar cut by beavers on the Upper Missouri, which he found to be 9 feet in circumference at the point of attack; but this was exceptional. This cutting is accomplished by the animals standing upon their hind feet and gnawing in parallel lines across the grain, then wrenching or biting out the chip between, and so steadily deepening the cut. The assertion that they can or do cause trees to fall in any desired direction is not justified by facts. Large trees are usually felled by the united efforts of a family of beavers.
Community Life and Architecture.—The architectural operations and coöperative life of these animals are very wonderful, although the statement, at one time commonly made, that beavers
