North American Beaver

Beavers are found in streams and lakes in both remote and settled areas. Using their huge front teeth, they can fell very large trees and branches. They prefer oak, ash, elm, willow, poplar, and birch trees. They use them, together with mud, stones, and sticks, to construct dams across fast-flowing streams. The damming of streams causes the area behind the dam to flood, producing a large marsh rich in water plants, insects, birds, and fish. Within the dam, beavers construct lodges that have various underwater entrance tunnels. They excavate mud from portion of the marsh with their front paws, constructing a system of canals along with they travel to and from their feeding areas. They also push floating logs and tow sticks and branches down the waterways to new dam sites. Beavers use scent to mark their territories. They deposit anal secretions and a strong-smelling substance called castoreum on rocks and mud throughout their territories. Beavers warn each other of danger by slapping their tails violently on the water surface.

Beavers have few vocalizations. They rely primarily on subtle body postures and scent to communicate with other beavers. The kits, babies, are the most vocal. Whimpers and whines are their most common vocalizations, used to solicit attention and made when eating, grooming and playing.

Beavers live in large, stable family groups consisting of one adult pair, their latest-born young, and the young born the previous year. Most beavers leave their family group at two years of age to find territories and mate.

Bark is the beaver's staple food. To ensure a constant supply of food throughout the winter, the beaver spends a great deal of time in the fall felling trees. The beaver tows the logs along the canals it has made and stores them under water. Beaver do not hibernate in winter, but in the northern parts of their range they generally only leave their lodges to feed from stored food supplies. During this time, they live in constant darkness and lose track of time. Aquatic plants, thistles, meadowsweet, leaves, twigs, seeds, and roots make up most of the beaver's summer diet.