There are two species of beaver. The European or Eurasian beaver (Castor fiber) and the North American beaver (Castor canadensis).
Beavers are the second largest rodent in the world after the capybara.
The beaver is mainly a nocturnal animal, meaning it is largely active at night.
The large front teeth of the beaver never stop growing. The beavers constant gnawing on wood helps to keep their teeth from growing too long.
Together beaver colonies create dams of wood and mud to provide still, deep water in order to protect against predators such as wolves, coyotes, bears or eagles, and also so they can float food and building material to their homes.
Once the dams are completed and ponds formed, beavers will work on building their homes called lodges in the middle. The dome shaped lodges, like the dams, are constructed with branches and mud. Lodges have underwater entrances, making entry tough for most other animals.
There are usually two dens within the lodge, one is for drying off after entering from the water and another, drier one, is where the family of up to four adults and six to eight young live.
There were once more than 60 million North American beaver. But due to hunting for its fur, its glands for medicine and because the beavers tree-felling and dams affect other land uses, the population has declined to around 12 million.
The beaver has a good sense of hearing, smell, and touch. It has poor eyesight, but does have a set of transparent eyelids which allow them to see under water.
Using their broad, scaly tail, beavers will forcefully slap the water as an alarm signal to other beavers in the area that a predator is approaching.
Beavers are slow on land but using their webbed feet, they are very good swimmers. A beaver can stay under water for up to 15 minutes.
Beavers are herbivores. They like to eat the wood of trees such as the aspen, cottonwood, willow, birch, maple, cherry and also eat pondweed and water lilies.
Adult beavers are around 3 feet long and have been known to weigh over 25 kg (55 lb). Females are as large or larger than males of the same age.
Beavers can live up to 24 years in the wild.
The beaver is the national animal of Canada, and features on the Canadian five-cent piece.
Beavers like to keep themselves busy, they are prolific builders during the night. Hence the saying "As busy as a beaver".