Castor

Beaver is called Eurasian Beaver in English, and there are 7 subspecies.

Beavers are active at night and rarely leave their holes during the day. They are good at swimming and diving and do not hibernate. Beavers have a unique ability to build dams. Wherever beavers live or have lived, there is a pond, lake or swamp. Beavers always tirelessly build dams with branches, stones and soft mud to block the path of streams. Small ones merge into ponds, and large ones can become lakes with an area of several hectares. Beavers have the ability to transform their own habitats. When entering a new habitat or when the water level in the habitat drops, beavers will use branches, mud and other things to build dams to store water to protect the cave entrance under water and prevent natural enemies from invading. In order to transport building materials for dams on the shore to the intercepting dam, beavers sometimes dig canals as long as hundreds of meters. Beavers move slowly and clumsily on land and do not move far from the water. They have weak self-defense capabilities, are timid, and like quiet environments. When they are frightened or in danger, they jump into the water and slap the water surface with their tails to warn their peers.

Beavers usually build nests near water. The nest chambers are made of branches and soil, 0.8-1.9m above the ground. There are three main types of beaver habitats: cave dwelling, nest dwelling, and cave-nest combination. Cave dwellings are permanent and temporary. Every spring flood season, as the ice and snow melt and the river floods, some beaver cave systems are flooded, forcing these beavers to migrate short distances and build simple caves in branch canals or small islands for temporary or refuge use. Permanent caves are places for beavers to overwinter and reproduce, and their structures are relatively complex. Cave systems are generally distributed in areas with higher river banks (more than 1.5m above the ice surface); cave-nest combinations (i.e., cave systems underground and a nest with a civil structure added on the ground) are mostly distributed on medium-sized river banks with a height of less than 1.5m above the ice surface. Simple nests are built in swamps or on islands in shallow water. These cave systems and cave nests are mostly located in the river bends where the water flow is gentle, the water depth is generally more than 2m, and the river width is about 15m. There are 2-4 cave entrances, most of which are underwater with willow trees. The cave passage is about 50cm high, about 56cm wide, up to 10m long, and generally about 5m. There is a bulging part in the cave passage, which is the place for beavers to eat, rest and give birth. The bulging chamber is generally 90cm high and about 85cm wide. Beavers bite poplar, willow branches and reed stems into thin and soft fibrous strips and lay them in the dormitory. The cave nest is composed of 2-5 cave passages connected together, with multiple air holes, and its openings are mostly hidden under the roots of trees on the shore. The nest is built with branches and part of the soil, generally about 1m above the ground, with no openings on the surface, and connected to the water body inside. Beavers often build 2-8 temporary caves on the shore near the cave nest for emergency shelter and temporary rest.

Beavers like to eat the tender branches, barks, and roots of many plants, as well as aquatic plants, young branches and leaves of poplars and willows, and barks. In summer, beavers also eat herbaceous plants on the shore, such as calamus, thorny thorns, water plantains, and grass plants. In autumn, beavers are active at dawn and dusk, biting branches and other things into pieces of about 1 meter, and carrying them to the deep water near the cave entrance to store them for winter consumption.

The natural enemies of beavers are mainly wolves, bears, and foxes. In addition, cattle often trample down beaver dens in winter, leaving beavers with nowhere to live in winter and dying.

Beavers reproduce once a year, mating in January and February, giving birth in April and May, with 1-6 pups per litter, a gestation period of about 106 days, a lactation period of about 2 months, and pups can swim 2 days after birth, and become sexually mature in the third year.

Due to ecological destruction and human factors in China, its distribution area has shrunk rapidly and it is on the verge of extinction. As of 2012, the number of beavers in the entire Ulungur River system fluctuated between 500 and 800, of which there were 35 families in the Burgen River, 2 families in the Chagan River, and about 130 families in the Burgen River to the Fuhai section of the Ulungur River. Mongolia's beavers are well protected and numerous. The upper reaches of the Burgen River are in Mongolia, about 40km from the border, which is the natural distribution area of beavers. It is said that artificial beavers have been relocated to several other rivers in Mongolia. In 1981, China established the only beaver nature reserve in China in the Burgen River Basin. The Burgen Beaver Reserve is located in the Burgen River Basin in Chagan Gol Township, Qinghe County, Altay Prefecture, Xinjiang. It mainly protects the river valley forest beaver habitat and the rare animal beaver in the world in the beaver distribution area along the 50km section of the Burgen River. The Burgen River is a river running from east to west. It originates in Mongolia and flows into China 50km later, where it merges with the Qinggeli River into the Ulungur River. The areas within 1km on both sides of this 50km-long river are all included in the scope of the beaver reserve. Among them, several sections with more beavers are designated as absolute protection areas.

Listed in the 2008 Red List of Endangered Species of the World Conservation Union (IUCN) ver 3.1 - Least Concern (LC).

Listed in the first level of the "List of National Key Protected Wildlife in China".

Protect wildlife and eliminate game.

Maintaining ecological balance is everyone's responsibility!

Distributed in: Belarus, China, France, Germany, Kazakhstan, Luxembourg, Mongolia, Norway, Russian Federation; Regionally extinct: Moldova, Portugal, Turkey, United Kingdom; Introduced: Austria, Belgium, Croatia, Czech Republic, Denmark, Estonia, Finland, Hungary, Italy, Latvia, Liechtenstein, Lithuania, Montenegro, Netherlands, Poland, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Ukraine; Uncertain origin: Bulgaria, Alaska in North America.
In China, it is only distributed in water bodies such as Qinghe River, Burgen River and Ulungur River in northeastern Xinjiang.
Beavers are found in cold temperate and subarctic forest rivers, live on the shore, and choose broad-leaved dense forests, shrub forests, and riverside valleys with slow and deep water flow as their habitats.

Beavers have obese bodies, with no obvious difference between males and females. They have short and blunt heads, small eyes, and short necks. They have short and wide limbs with five toes. They have short forelimbs, small feet, and strong claws; their hind limbs are strong and powerful, with webbed hind feet that reach the toes. The claws of the second toe are split and can be used for combing. They have large, flat tails with horny scales and sparse hair. They have short ears with waterproof valves inside. They have well-developed subcutaneous muscles on their backs, and strong tendons attached to their coccyx. Both males and females have a pair of scent glands located on both sides of the anus. The scent glands are oblate rod-shaped, light gray, with protrusions on the inner epidermis, forming wrinkles in the glandular capsule. Their secretions (castor scent) are light yellow.
The beaver's body is covered with long and thick guard hairs and dense and soft down. The guard hai