It belongs to the Castoridae family of Rodentia order, with the scientific name of Castor fiber (Latin), and Eurasian Beaver (English).       

It is the largest rodent of China, leading a half-water dwelling life. It is 74 to 100 centimeters in body length and about 25 kilograms in weight. It has small head and eyes, short neck, limbs and ears. Its auricle shell can be turned upwards, preventing water injection. Its body hair is tan and brown, thickly covered with fuzz. The hind leg has webs from toes to claws, which is suitable for thrashing. Its large and flat tail is about 40 centimeters long, covered with scutellum, functioning as rudder. In the front of anal glands is a pair of musk glands that are able to secret "beaver incense".

It inhabits in riversides of borders of coniferous forests and mixed broadleaf-conifer forests, living in caves. It is good at swimming and diving, mainly moving about at night and feeding on fresh and tender barks, twigs and reeds. The caves are usually dug below the root of trees by the riverside.

It once had comparatively extensive distribution in northern Eurasia. Because of the precious fur, it had been hunted excessively for a long time, and the distribution was sharply reduced. In China it is only distributed in the area of Burgen River of Xinjiang Uygur Autonomous Region, where natural protection area has been established now.