Collier's New Encyclopedia (1921)/Beaver
BEAVER, the English name of the well known rodent mammal castor fiber, or, more loosely, of any species belonging to the genus castor. The animal so designated has in each jaw two powerful incisor teeth, coated with hard enamel, by means of which it is enabled to cut across the trunks of the trees which it requires for its engineering schemes. The hind feet are webbed, and one of the five toes has a double nail. The tail is flattened horizontally, and covered with scales. Large glandular pouches secrete an odoriferous substance called castoreum. The castor fiber exists through the temperate and colder parts of this country.