North American Beaver Castor canadensis

The Beaver is a large, semi-aquatic rodent. There are two living species: the North American and the European. The latter is slightly larger and the second largest rodent after the Capybara. The North American range is from Canada through USA to Mexico. It has also been introduced to South America and northern Europe (but cannot interbreed with the European species). Another, unrelated, American rodent is also called a Mountain Beaver.

They spend much of their time in water, living in monogamous family groups in a lodge built in the river bank or their dam. They are vegetarian and more active at night.

They are well-known for chiselling down small trees and for building dams which can filter sediment from water and improve flood management and water quality. The deep ponds allow escape from land predators and provide an area of unfrozen water in winter.

Their tails are flat and hairless, used as rudders. They have long outer hairs and fine, short, close inner fur. They also have a layer of fat to enable them to stand low temperatures.

They have been extensively hunted for their waterproof fur and for "castoreum", an oily, water-proofing secretion, used in medicines and perfumes.