American beaver

Phylum Chordata
Class Mammalia
Order Rodents
Family Castoridae
Scientic name Castor canadensis
French name Castor
Size Length: 90 to 120 cm
Status Common species

Distinguishing features The beaver has a brown pelt. Its hind feet are webbed. It has a broad, flat, scaly tail and prominent long, orange incisors.

Reproduction Beavers generally form lifelong pairs. They mate under the ice in January or February. Gestation lasts from 103 to 120 days and the female bears one litter per year, of one to eight kits. They are weaned at about 7 to 10 weeks, and remain with the colony for two years. When the parents are absent, the elder kits help raise their younger siblings by cleaning their fur, watching over them and bringing them food.

Diet Beavers are exclusively vegetarian, and feed mainly on tree bark, leaves and buds. Their favourites are trembling aspen, birch, maple, alder and willow. In summer they love to eat aquatic plants, such as duckweed, the roots of water lilies and pondweed. When fall arrives, they gather a huge pile of branches on the lake or river bottom to tide them over the cold months. They also feed on roots and stalks of aquatic plants in winter.

Predators Beavers are hunted mostly by humans, for their fur, and by otters. They may also be attacked by lynx, coyotes, bears, wolves, fishers and wolverines. The beaver population shrank drastically in the early 20th century because of the fur trade. After many successful attempts to reintroduce them in different areas, beavers are abundant today.

Habitat They are found throughout most of Canada and the United States, living in lakes and marshes with wooded shorelines. Trees such as trembling aspen provide them with plenty of food. Beavers build dams to adapt their natural surroundings, with an impact on the local wildlife and plants. Many animal species (ducks, muskrats, mink, frogs, snakes, turtles, fish, insects) and aquatic plants benefit from the ponds or marshes created by beavers.

Ecology Beavers live in colonies of up to a dozen individuals, consisting of parents and their families (the young from the spring and those from the previous year). They build dams to flood their surroundings, in part to gain access to more food. The felling of trees and flooding may interfere with human activity, however. They use branches, grass, mud and stones to make their lodges and dams. Sometimes they simply dig a burrow in the riverbank or the shore.

At the Biodôme Video camera in the beaver lodge allows visitors to watch them sleeping, moving branches around and grooming themselves. Aside from the branches provided as food, they also eat fruit, vegetables, pellet meal and other plants. The beavers at the Biodôme are generally most active late in the day. In fall they can often be observed piling up branches near their