American Beaver

The lodge has one or more underwater entrances; living quarters are in a hollow near the top. Wood chips on the floor absorb excess moisture, and a vent admits fresh air. The chief construction materials in the northern parts of the American Beaver's range-poplar, aspen, willow, birch, and maple-are also the preferred foods. To fell a tree, the beaver gnaws around it, biting out chips in a deep groove. Small trees 2 to 6 inches (50-150 mm) in diameter are usually selected, though occasionally larger ones as much as 33 inches (850 mm) thick are felled; a willow 5 inches (125 mm) thick can be cut down in three minutes. The beaver trims off branches, cuts them into convenient sizes (about 1 to 2 inches /25-50 mm thick and 6 feet/1.8 m long), and carries them in its mouth to the dam site.