American beavers are stocky animals that have a compact body and short legs. They are aquatic rodents and have a number of adaptations that make them adept swimmers including webbed feet and a broad, flat tail that is covered with scales. They also have an extra set of eyelids which are transparent and close over their eyes enabling beavers to see while underwater.
Beavers have a pair of glands located at the base of their tail called castor glands. These glands secrete an oil that has a distinct musk odor, making it great for use in marking territory. Beavers also use the castor oil to protect and waterproof their fur.
Beavers have very large teeth in proportion to their skull. Their teeth and are super-sturdy thanks to a coating of tough enamel. This enamel is orange to chestnut brown in color. Beavers' teeth grow continuously throughout their lives. As beavers chew through tree trunks and bark, their teeth get warn down, so the continuous growth of their teeth ensures they always have a good set of chompers available to them. To further assist them in their chewing endeavors, beavers have strong jaw muscles and singificant biting strength.
Beaver build lodges, which are dome-shaped shelters made of woven sticks, branches, and grass that are plastered together with mud. The entrance to a beaver lodge is located below the surface of the water. Lodges can be burrows built into pond banks or mounds built in the middle of a pond.
Beavers live in family units called colonies. A beaver colony commonly includes as many as 8 individuals. Members of the colony establish and defend a home territorial.