This hard-working and diligent animal is one of the largest rodent species throughout the world. Their fur consists of two layers: the undercoat and the outer coat. The undercoat of the Eurasian beaver is soft, thick and dark-grayish in color. The outer coat is longer, covered with tough guard hairs that are reddish-brown in color. Northern populations of Eurasian beaver usually have darker coloring. The scaly tail is naked, broad, flattened horizontally and oval-shaped. The Eurasian beaver has short legs, small ears, blunt muzzle and valvular nostrils. This animal has nictitating membranes on its eyes, which close, as the beaver goes under water. Coloration of their feet varies from dark-brown to black. Each foot has 5 digits while rear feet are webbed with a split nail inside of two toes, which they use for grooming.
These rodents are semi-aquatic animals, and their main habitat is freshwater systems such as rivers, streams, lakes and ponds. They usually prefer forested areas, though can also be found in swamps and marshes. Area of their distribution covers a huge territory from north-eastern Europe to Central Eurasia, stretching southward from Norway on Scandinavian Peninsula to Denmark, through Germany to the Alps, and then eastward, reaching as far as Mongolia.
Eurasian beavers are social animals, gathering in colonies. Beaver colonies have only one dominant breeding pair and can include up to 12 individuals. They construct burrows in the bank of a river or a pond. In the areas where the riverbank is unsuitable for habitation, they construct their lodges away from shore, using sticks and mud. They are mainly nocturnal, though can also be active by day. The Eurasian beavers are active all year round. However, in the northernmost areas of their range, the beavers rarely come above the ice surface during the winter. For this reason, during the autumn months, they store food supplies in the water to help them get through the winter. They are extremely territorial animals. The beavers use olfactory signals, marking their territory with castereum.
The Eurasian beaver is a herbivorous (folivorous and lignivorous) animal. During the winter, their diet mainly consists of woody vegetation such as aspen tree, birch tree or willow. In the summer months, however, these rodents consume aquatic plants, bark, leaves, roots, buds, twigs, shoots as well as crops in agricultural areas.
Eurasian beavers have monogamous mating system with only one breeding pair per colony. The breeding season takes place in January-February with the gestation period, lasting 60-128 days. The female usually gives birth to 1-3 babies, sometimes up to 6 and more. The mother takes care of the young, cleaning them and providing with food. The babies are weaned at the age of 6 weeks, after which sub-adults in the colony help them with food, bringing them soft bark and small sticks, until the young reach the age of 3 months. Then, by the age of 1.5 - 2 years, they leave, sometimes being driven out by the adult female. The beavers start mating at 3 years old.
Pollution of rivers and streams, loss of habitat as well as road accidents are among major threats to the Eurasian beaver population. In Mongolia, the species is illegally hunted. On the other hand, in north-west of Russia and in Finland, they are threatened by the competition with the introduced population of American beaver.
The overall population of the Eurasian beaver is currently increasing but no overall population estimate is available. On the IUCN Red List, the species is classified as Least Concern (LC). In 2006, the total population of the Eurasian beavers was estimated at 639.000 individuals with China, holding 700 beavers and Mongolia - 150.
Eurasian beavers play important role in the ecosystem of their range. By building dams, they alter the water flow, thus flooding large areas of uplands and attracting new species of fish, amphibians and birds. Then, in a year, the woody plants die off under the water, and a forested ecosystem gives way to an open water ecosystem. In addition, due to browsing woody vegetation, these animals help maintain woody plants in the sapling stages over long periods of time.