Wildlife
Beaver (Castor canadensis):
 The beaver is the largest rodent in North America. Adults are from 36 to 48 inches long, including a flattened 10- to 16-inch tail. The wide flat tail can be used as a rudder while swimming and as a support on land. Beavers will slap their tail loudly on the water as a sign of warning. They have robust bodies with large webbed hind feet and small front feet. Their pelt is typically reddish-brown and ranges in color from pale yellow to black. Beavers have large, sharp, front teeth, small ears and nostrils that can be closed for swimming under water. Adults weigh from 40 to more than 70 pounds.
 The beaver is one of the few animals able to alter its own habitat. Small streams are dammed by beavers which results in the creation of a pond. Canals are built to transport food and building materials to the pond. The dam and lodge are constructed from sticks and mud. Where streams are too large or swift to dam but provide ample water throughout the year, beavers may use bank dens. The same lodge is used by a beaver family year after year so some can become quite large (more than 6 feet high and 15 feet in diameter).
Beavers eat a variety of vegetation, including the leaves and bark of deciduous trees and shrubs as well as roots and stems of aquatic plants. During the fall, beavers cache their food supply of branches in the water, near the lodge or bank den. Materials from the cache are eaten during the winter as thick ice typically prevents beavers from going ashore. When food becomes limited beavers must travel further from their homes. This increases the danger from predators. When an area is cleared of food, the family relocates to a new area. On Togiak Refuge important predators of beavers include brown bears, wolves, wolverines, and people.
Most beavers become sexually mature during their second year. Mating occurs in January or February and from 1 to 6 kits are born in late April to June. The kits' eyes are open at birth and they can swim immediately. Young live with their parents until they are two years old and then disperse to find their own homes.
Togiak Refuge is conducting beaver cache surveys to learn more about these animals.
Resources:
Burt, William H. and Richard P. Grossenheider. 1980. Peterson field guide to mammals. Houghton Mifflin Company. Boston Massachusetts.
Alaska Geographic Society. 1996. Mammals of Alaska: a comprehensive field guide from the publishers of Alaska geographic. The Alaska Geographic Society. Anchorage Alaska.
For more information, visit the Alaska Department of Fish and Game's wildlife notebook pages.
Last updated: July 24, 2008
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