The North American beaver (Castor canadensis), one of two extant beaver species (the other being the Eurasian beaver), is native to North America and has been introduced to parts of South America and Europe. It serves as a national symbol of Canada and the official state mammal of Oregon and New York. These beavers are found throughout the continental U.S., Canada, southern Alaska, and parts of northern Mexico.
Commonly referred to simply as “beaver” in Canada and the U.S., they can be confused with the mountain beaver (Aplodontia rufa). Other names include American and Canadian beaver for clarity. The North American beaver is the largest rodent in North America, averaging 11 to 32 kg, with adult sizes depending on the region.
Beavers are semiaquatic, possessing adaptations such as paddle-shaped tails, webbed hind feet, and a nictitating membrane that allows them to see underwater. They are primarily nocturnal and excellent swimmers, able to hold their breath for up to 15 minutes.
They build lodges from sticks, twigs, and mud, sometimes creating dams to form ponds that provide safety from predators. These structures also foster habitats for other wildlife and help prevent soil erosion and flooding. Beavers primarily focus on building and repairing their dams in the fall, preparing for winter by managing water levels.
