When sites are available, beavers burrow in the banks of rivers and lakes they also transform less suitable habitats by building dams. Gnawing trees with their strong teeth and powerful jaws, they create massive log, branch, and mud structures to block streams and turn fields and forests into the large ponds that beavers love. The Dome like beaver homes, called lodges, are also constructed of branches and mud. They are often located in the middle of ponds and can only be reached by underwater entrances. Beavers are among the largest of rodents. They are herbivores and prefer to eat leaves, bark, twigs, roots, and aquatic plants. These large rodents move with an ungainly waddle on land but are graceful in the water, where they use their large, webbed rear feet like swimming fins, and their paddle-shaped tails like rudders. These attributes allow beavers to swim at speeds up to five miles an hour. They can remain underwater for 15 minutes without surfacing, and have a set of transparent eyelids that function much like goggles. Their fur is naturally oily and waterproof. These animals are active all winter, swimming and foraging in their ponds even when a layer of ice covers the surface.
