Beavers (genus Castor) are large, semi-aquatic rodents found in the Northern Hemisphere. There are two species: the North American beaver (Castor canadensis) and the Eurasian beaver (C. fiber). Beavers are the second-largest rodents, after capybaras, and can weigh up to 50 kg. They have sturdy bodies, large heads, long teeth for chewing, brown or gray fur, hands for front feet, webbed back feet, and flat, scaly tails. The two species have differences in skull shape, tail shape, and fur color. Beavers live in freshwater areas like rivers, lakes, and ponds. They eat tree bark, aquatic plants, grasses, and sedges.
Beavers build dams and lodges using branches, plants, rocks, and mud. They cut down trees for these materials. Dams slow down water flow, and lodges provide shelter. Their work creates wetlands that many other animals use. Because they greatly impact their environment, beavers are a keystone species. Adult male and female beavers form monogamous pairs and raise their young together. After their first year, young beavers help their parents fix dams and lodges. Older siblings may help care for new babies. Beavers mark their territories with scent mounds made from mud, debris, and castoreum, a fluid they produce. They can also identify close relatives by their secretions and tend to accept them as neighbors.
In the past, people hunted beavers for their fur, meat, and castoreum. Castoreum was used in medicine, perfume, and food flavoring. Beavers’ fur drove the fur trade. Overhunting almost wiped out both species before conservation efforts began in the 19th and early 20th centuries. Their populations have since recovered, and they are now listed as species of least concern by the IUCN Red List.
