Classification: Fur Bearing Wildlife Species
Status: An abundant, important fur animal and water conservationist. Its value as a fur animal was responsible for much of the early exploration of North America. Is one of the most intensively studied furbearers in North America. Official Montana furbearer managed and protected by regulated fur harvest seasons.
Identifying Characteristics: The largest rodent in North America north of Panama. On land is a large, clumsy, hump-backed animal. In the water, becomes sleek and torpedo-shaped. Propels itself with powerful webbed hind feet. Beavers use their large dorsally flattened, scale-covered tail to maneuver in water. Slapping the tail on the water surface is used as a signal of alarm. Beaver also slap their tails during periods of play. Split nail on the second hind toe is used for grooming. Incisors are large and continually growing. Fur is rich brown with black to reddish guard hairs. Underfur is soft and extremely dense with excellent insulating qualities. Both sexes have a pair of anal glands and castor sacs located ventrally. Beavers emit anal gland secretions year round.
Total length: 34 to 40 inches. Weight: 30 to 60 pounds and sometimes heavier.
Habitat: Occupies a wide variety of habitats in North America. Water and associated woody vegetation are the most essential components of beaver habitat. Ideal beaver living sites include ponds, lakes, streams, and rivers.
Food Habits: Beavers are strict herbivores. Beavers eat a variety of woody and herbaceous species. Willows, mountain alder, and aspen are important foods. Will also consume herbaceous vegetation during summer. Much of the woody vegetation beavers cut is not used for food. Caches woody vegetation near shore for winter food.
Life History: Builds stick and mud dams across streams. Mostly nocturnal. May build large conical houses at the edge of a lake or burrow into the bank for a den along rivers. Beaver life is based on a family unit consisting of a pair of adults, yearlings, and kits. Breeds form January through March. 2 to 4 young are born after a 105 to 107 day gestation period. One litter per year is produced. Two-year-olds are eventually driven from or leave the parental home.
Similar Species: River otter - tail covered with fur. Muskrat - smaller, tail slender.
The beaver is the largest North American rodent. A common furbearer, the beaver inhabits waterways of every North American state and Canadian Province. A unique paddle shaped tail distinguishes the species and self-sharpening teeth allow beavers to mow down sizable trees. Beaver often alter the landscape with the construction of dams, canals and lodges. Beaver are territorial as long as the habitat will support family groups called "colonies". Beaver are powerful animals both on land and in the water.