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American Beaver

Its fur has a range of many different colors but is usually seen as dark brown. The beaver coat comprises two types of hair. The outer section is coarse and long and covers an inner layer which is much finer. It has a rounded head, a large flat paddle-shaped tail and webbed hind feet. The unwebbed front paws are smaller, with claws. This is the largest rodent found in North America and the second largest rodent in the world (the largest rodent being the South American capybara).

Beavers are mainly active at night. They are excellent swimmers but are more vulnerable on land and tend to remain in the water as much as possible. They are able to remain submerged for up to 15 minutes. A scent gland near their genitals secretes an oily substance known as castoreum which is used to waterproof its fur. A thick layer of fat under its skin insulates the beaver from its cold water environment. The eyes are covered by a nictitating membrane which allows the beaver to see underwater. Their nostrils and ears are sealed while submerged. The flat, scaly tail is used to signal danger and also serves as a source of fat storage.

They construct their homes, or "lodges," out of sticks, twigs, and mud in lakes or streams. These lodges may be surrounded by water, or touching land, including burrows dug into river banks. They are well known for building dams across streams and constructing their lodge in the artificial pond which forms. The entrance to the lodge or burrow is located underwater. In the event of danger, a beaver slaps its tail on the water to warn other family members.

The dam is constructed using sections of deciduous trees, especially birch, aspen, willow and poplar. The inner bark, twigs, shoots and leaves of such trees are also an important part of the beaver's diet. The trees are cut down using their strong incisor teeth. Their front paws are used for digging and carrying and placing materials. Some researchers have shown that the sound of running water dictates when and where a beaver builds its dam. Besides providing a safe home for the beaver, beaver ponds also provide habitat for waterfowl and other aquatic animals. Their dams help reduce soil erosion and can help reduce flooding. During the summer, beavers eat grasses, cattails, water lilies and other aquatic plants.

Beavers usually mate for life. The young beaver "kits" typically remain with their parents for up to two years. The American Beaver is distinguished from its cousin, the European Beaver, by its stronger teeth and greater reproductive capacity.

An emerging problem is the descendants of an introduced population in Tierra del Fuego, Argentina. The escapees from a farmed population of 25 animals has bloomed to an estimated 100,000; the drastically different ecosystem has led to incredible environmental damage, as the ponds created by the beavers have no ecological purpose (wetlands do not form there as they do in the beavers' native territory) and there are no native, large predators. They have also been found to cross saltwater to islands northward; a possible encroachment on the mainland has naturalists highly concerned.

Beaver meat is similar tasting to lean beef, but care must be taken to prevent contamination from the animal's strong castor (musk) gland. It is usally slow-cooked in a broth, and was a valuable food source to Native Americans. In parts of North America, fried pastries called beaver tails may be found. Despite their name, they contain no beaver.

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