Castor
2 species
Beavers are large, semiaquatic rodents in the genus Castor native to the temperate Northern Hemisphere. There are two extant species: the North American beaver (Castor canadensis) and the Eurasian beaver (C. fiber). Beavers are the second-largest living rodents after the capybaras. They have stout bodies with large heads, long chisel-like incisors, brown or gray fur, hand-like front feet, webbed back feet and flat, scaly tails. The Eurasian beaver has a more elongated skull with a more triangular nasal bone opening, lighter fur color and a narrower tail. The animals can be found in a number of freshwater habitats, such as rivers, streams, lakes and ponds. They are herbivorous, consuming tree bark, aquatic plants, grasses and sedges.
Beavers build dams and lodges using tree branches, vegetation, rocks and mud; they chew down trees for building material. Dams impound water and lodges serve as shelters. Their infrastructure creates wetlands used by many other species, and because of their effect on other organisms in the ecosystem, they are considered a keystone species. Adult males and females live in monogamous pairs with their offspring. When they are old enough, the young will help their parents repair dams and lodges and may also help raise newly born offspring. Beavers hold territories and mark them using scent mounds made of mud, debris and castoreum, a urine-based substance excreted through the beaver's castor sacs. Beavers can also recognize their kin by their anal gland secretions and are more likely to tolerate them as neighbors.
Historically, beavers have been hunted for their fur, meat and castoreum. Castoreum has been used in medicine, perfume and food flavoring, while beaver pelts have been a major driver of the fur trade. Before protections began in the 19th and early 20th centuries, overhunting had nearly exterminated both species. Their populations have rebounded, and they are both listed as least concern by the IUCN Red List of mammals. In human culture, the beaver symbolizes industriousness and is the national animal of Canada.
The IUCN Red List of mammals lists both beaver species as least concern. The North American beaver is widespread throughout most of the United States and Canada and can be found in northern Mexico. The species was introduced to Finland in 1937 (and then spread to northwestern Russia) and to Tierra del Fuego, Patagonia, in 1946. The introduced population in Finland has been moving closer to the range of the native Eurasian beaver as of 2019. Historically, the North American beaver was trapped and almost extirpated because its fur was highly sought after. Protections have allowed the beaver population on the continent to rebound to an estimated 6–12 million by the late 20th century; this is a fraction of the originally estimated 60–400 million North American beavers before the days of the fur trade. The introduced population in Tierra del Fuego is estimated at 35,000–50,000 individuals as of 2016.
The Eurasian beaver's range is not contiguous but fragmented. It was historically widespread throughout Eurasia, but overhunting had greatly reduced its range by the early 20th century. In Europe, beavers were reduced to isolated populations in the Rhône of France, the Elbe in Germany, southern Norway, the Neman river and Dnieper Basin in Belarus and the Voronezh river in Russia with combined numbers estimated at 1,200 individuals. The beaver has since returned to parts of its former range because of management measures and reintroductions. Beaver populations now range from Spain and France, through central and eastern Europe and into Scandinavia and Russia. Beginning in 2009, beavers have been reintroduced successfully to parts of Great Britain. In 2020, the total beaver population in Europe was estimated at over one million. Small native populations are also present in Mongolia and northwestern China; their numbers were estimated at 150 and 700 respectively as of 2016. Under New Zealand's Hazardous Substances and New Organisms Act 1996, beavers are classed as a "prohibited new organism" preventing them from being introduced into the country.
Beavers are large, semiaquatic rodents in the genus Castor native to the temperate Northern Hemisphere. There are two extant species: the North American beaver (Castor canadensis) and the Eurasian beaver (C. fiber). Beavers are the second-largest living rodents after the capybaras. They have stout bodies with large heads, long chisel-like incisors, brown or gray fur, hand-like front feet, webbed back feet and flat, scaly tails. The Eurasian beaver has a more elongated skull with a more triangular nasal bone opening, lighter fur color and a narrower tail. The animals can be found in a number of freshwater habitats, such as rivers, streams, lakes and ponds. They are herbivorous, consuming tree bark, aquatic plants, grasses and sedges.
Beavers build dams and lodges using tree branches, vegetation, rocks and mud; they chew down trees for building material. Dams impound water and lodges serve as shelters. Their infrastructure creates wetlands used by many other species, and because of their effect on other organisms in the ecosystem, they are considered a keystone species. Adult males and females live in monogamous pairs with their offspring. When they are old enough, the young will help their parents repair dams and lodges and may also help raise newly born offspring. Beavers hold territories and mark them using scent mounds made of mud, debris and castoreum, a urine-based substance excreted through the beaver's castor sacs. Beavers can also recognize their kin by their anal gland secretions and are more likely to tolerate them as neighbors.
Historically, beavers have been hunted for their fur, meat and castoreum. Castoreum has been used in medicine, perfume and food flavoring, while beaver pelts have been a major driver of the fur trade. Before protections began in the 19th and early 20th centuries, overhunting had nearly exterminated both species. Their populations have rebounded, and they are both listed as least concern by the IUCN Red List of mammals. In human culture, the beaver symbolizes industriousness and is the national animal of Canada.
The IUCN Red List of mammals lists both beaver species as least concern. The North American beaver is widespread throughout most of the United States and Canada and can be found in northern Mexico. The species was introduced to Finland in 1937 (and then spread to northwestern Russia) and to Tierra del Fuego, Patagonia, in 1946. The introduced population in Finland has been moving closer to the range of the native Eurasian beaver as of 2019. Historically, the North American beaver was trapped and almost extirpated because its fur was highly sought after. Protections have allowed the beaver population on the continent to rebound to an estimated 6–12 million by the late 20th century; this is a fraction of the originally estimated 60–400 million North American beavers before the days of the fur trade. The introduced population in Tierra del Fuego is estimated at 35,000–50,000 individuals as of 2016.
The Eurasian beaver's range is not contiguous but fragmented. It was historically widespread throughout Eurasia, but overhunting had greatly reduced its range by the early 20th century. In Europe, beavers were reduced to isolated populations in the Rhône of France, the Elbe in Germany, southern Norway, the Neman river and Dnieper Basin in Belarus and the Voronezh river in Russia with combined numbers estimated at 1,200 individuals. The beaver has since returned to parts of its former range because of management measures and reintroductions. Beaver populations now range from Spain and France, through central and eastern Europe and into Scandinavia and Russia. Beginning in 2009, beavers have been reintroduced successfully to parts of Great Britain. In 2020, the total beaver population in Europe was estimated at over one million. Small native populations are also present in Mongolia and northwestern China; their numbers were estimated at 150 and 700 respectively as of 2016. Under New Zealand's Hazardous Substances and New Organisms Act 1996, beavers are classed as a "prohibited new organism" preventing them from being introduced into the country.
