Eurasian beaver


The Eurasian beaver or European beaver is a species of beaver widespread across Eurasia, with a rapidly increasing population of at least 1.5 million in 2020. The Eurasian beaver was hunted to near-extinction for both its fur and castoreum, with only about 1,200 beavers in eight relict populations from France to Mongolia in the early 20th century. It has since been reintroduced into much of its former range and now lives from Western, Southern, Central and Eastern Europe, Scandinavia, Russia through China and Mongolia, with about half the population in Russia. It is listed as least concern on the IUCN Red List.

Taxonomy

Castor fiber was the scientific name used by Carl Linnaeus in 1758, who described the beaver in his work Systema Naturae. Between 1792 and 1997, several Eurasian beaver zoological specimens were described and proposed as subspecies, including:
These descriptions were largely based on very small differences in fur colour and cranial morphology, none of which warrant a subspecific distinction.
In 2005, analysis of mitochondrial DNA of Eurasian beaver samples showed that only two evolutionarily significant units exist: a western phylogroup in Western and Central Europe, and an eastern phylogroup in the region east of the Oder and Vistula rivers. The eastern phylogroup is genetically more diverse, but still at a degree below thresholds considered sufficient for subspecific differentiation.

Description

The Eurasian beaver's fur colour varies between regions. Light, chestnut-rust is the dominant colour in Belarus. In Russia's Sozh River basin, it is predominantly blackish brown, while in the Voronezh Nature Reserve beavers are both brown and blackish-brown.
The Eurasian beaver is one of the largest living rodent species and the largest rodent native to Eurasia. Its head-to-body length is with a long tail length. It weighs around. By the average weights known, it appears to be the world's second heaviest rodent after the capybara, and is slightly larger and heavier than the North American beaver. One exceptionally large recorded specimen weighed, but it is reportedly possible for the species to exceptionally exceed.

Differences from North American beaver

Although the Eurasian beaver appears superficially similar to the North American beaver, there are several important differences, chief among these being that the North American beaver has 40 chromosomes, while the Eurasian beaver has 48. The two species are not genetically compatible: the result of over 27 attempts in Russia to hybridise the two species was just one stillborn kit, bred from the pairing of a male North American beaver and a female Eurasian beaver. The difference in chromosome count makes interspecific breeding unlikely in areas where the two species' ranges overlap.

Fur

The guard hairs of the Eurasian beaver have longer hollow medullae at their tips. There is also a difference in the frequency of fur colours: 66% of Eurasian beavers overall have beige or pale brown fur, 20% have reddish brown, nearly 8% are brown, and only 4% have blackish coats; among North American beavers, 50% have pale brown fur, 25% are reddish brown, 20% are brown, and 6% are blackish.

Distribution and habitat

The Eurasian beaver is recovering from near extinction, after depredation by humans for its fur and for castoreum, a secretion of its scent gland believed to have medicinal properties. The estimated population was only 1,200 by the early 20th century. In many European nations, the Eurasian beaver became extinct, but reintroduction and protection programmes led to gradual recovery so that by 2020, the population was at least 1.5 million. It likely survived east of the Ural Mountains from a 19th-century population as low as 300 animals. Factors contributing to their survival include their ability to maintain sufficient genetic diversity to recover from a population as low as three individuals, and that beavers are monogamous and select mates that are genetically different from themselves. About 83% of Eurasian beavers live in the former Soviet Union due to reintroductions.

Continental Europe

The Eurasian beaver lives in almost all countries in continental Europe, from Spain and France in the west, to Russia and Moldova in the east, and Montenegro, Serbia and Bulgaria in the southeast. In 2022 and again in 2025 beaver signs were found and documented in Portugal, in regions near the border with Spain. The only significant areas where it has no known population are the southern Balkans: Albania, Kosovo, Northern Macedonia, Greece and European Turkey. It is also not known to be present in the microstates of Andorra, Monaco, San Marino and Vatican City.
In Spain, the beaver was extirpated in the 17th century. In 2003, 18 beavers were unofficially released. Current range includes the Ebro river in La Rioja, Navarre, and province of Zaragoza; the Zadorra river up to Vitoria-Gasteiz, the Arga river up to Pamplona, the Huerva river up to Mezalocha, and the Jalón river into the province of Soria. In November 2021, a young beaver was photographed for the first time outside the Ebro basin, in the upper Douro river in Soria. In 2020, the population was estimated to be more than 1,000. In June 2024, a beaver was sighted at the Tagus river basin near Zorita de los Canes.
In Portugal, the beaver was distributed mostly in the main river basins north of the Tagus River, until it was extirpated around 1450. In 2023, signs of beaver activity were found on the Douro river about 5 km from the Spanish border. In 2025, it was confirmed that the beaver had returned to Portugal, at the Douro International Park.
In France, the Eurasian beaver was almost extirpated by the late 19th century, with only a small population of about 100 individuals surviving in the lower Rhône valley. Following protection measures in 1968 and 26 reintroduction projects, it re-colonised the Rhône river and its tributaries, including the Saône, and other river systems such as Loire, Moselle, Tarn and Seine. In 2011, the French beaver population was estimated at 14,000 individuals living along of watercourses. In 2022, its range was estimated to have increased to of watercourses.
In the Netherlands, beavers were completely extirpated by 1826. Due to official reintroductions since 1988, beavers are now found in most parts of the country, in particular the south, centre and north-west. The population was around 3500 in 2019.
In Belgium the beaver was extirpated in 1848. Current populations are descendants of animals released in the Ardennes in 1998–2000 and in Flanders in 2003. Some beavers also arrived in Flanders from the Netherlands in 2003. In 2018, the population was 2,200–2,400, with Flanders having around 400 beavers and Wallonia 1,800–2,000 beavers.
In Germany, around 200 Eurasian beavers survived at the end of the 19th century in the Elbe river system in Saxony, Saxony-Anhalt and Brandenburg. Official reintroduction programs, in particular in Bavaria, resulted in major population growth and beavers are now found throughout most of eastern and southern Germany, with strongly established disjunct populations in the west. By 2019, beavers numbered above 40,000, and appear in many urban areas.
In Poland, as of 2014, the beaver population had grown to 100,000 individuals.
In Switzerland, the Eurasian beaver was hunted to extirpation in the early 19th century. Between 1956 and 1977, 141 individuals from France, Russia and Norway were reintroduced to 30 sites in the Rhône and Rhine catchment areas. As of 2019, Switzerland had an estimated 3,500 beavers, with permanent beaver presence along most larger rivers of the Swiss plateau and the Swiss Alps.
In Italy, beavers returned in 2018 after an absence of almost 500 years, when they were spotted in the Friuli-Venezia Giulia region.
In Romania, beavers became extinct in 1824, but were reintroduced in 1998 along the Olt River, spreading to other rivers in Covasna County. In 2014, the animals were confirmed to have reached the Danube Delta.
In Russia, by 1917, beaver populations remained in four isolated territories: in the Dnieper basin; in the Don basin; in the northern Urals and in the upper reaches of the Yenisei along the Azas river. The total number of beavers did not exceed 900 heads. Beaver hunting was banned in 1922. In 1923, a hunting reserve was organised in the Voronezh region along the Usman river, which in 1927 was transformed into the Voronezh State Reserve. At the same time, two more such reserves were created: Berezinsky and Kondo-Sosvinsky. 1927 also included the first attempts to reintroduce beavers in other areas. As a result, by the end of the 1960s, the beaver's range in the Soviet Union was almost as large as in the 17th century. The beavers' growing numbers made commercial capture possible again. In 2016, there were an estimated 661,000 beavers in Russia; in 2019, the estimate was 774,600.
In the lands that made up the Soviet Union, almost 17,000 beavers were translocated from 1927 to 2004. Some 5,000 of these went to Ukraine, Belarus, the Baltic States and Kazakhstan.
In Bulgaria, fossil, subfossil and subrecent remains have been found in 43 localities along 28 lowland rivers, from Struma and Maritsa in the south till the Danube in the north, while the last finds from Nicopolis ad Istrum date to the 1750–1850 period. In 2021, the Eurasian beaver was confirmed to have returned to Bulgaria.
In Serbia, beavers were mostly extinct by the 1870s, with the last specimens being seen around 1900–1902. In 2004, 31 beavers were reintroduced in the Zasavica reserve by the Biology Faculty of the Belgrade University in collaboration with the Bavarian Science Society, and 45 beavers were released in the Obedska bara reserve. They spread quickly. By 2020, they had spread north, west and east, inhabiting rivers in the Sava-Danube system, they were found in the capital Belgrade, and had spread to neighbouring Bosnia and Herzegovina.
In 1999, after a beaver was shot in Northern Serbia that had dispersed from Hungary's re-established population, a reintroduction program was initiated also in Bosnia and Herzegovina. Between 2005 and 2006, a total of 40 were introduced into the Semešnica and Sokočnica rivers in Bosnia and Herzegovina. Based on a recent study, the current reserve network should be expanded further to assist the colonisation process of the Eurasian beavers to reduce mortality and mitigate potential conflicts with people.
In Croatia, the Eurasian beaver was hunted to extinction by the end of the 19th century. It was reintroduced from 1996 to 1998 in the Sava and Drava rivers.
Beavers spread from Croatia into Slovenia along the Sava, Drava, Mura and Kolpa rivers.
In Greece, the Eurasian beaver was present in the Last Glacial Period; remains have been found in Epirus. Beaver remains from the Neolithic have been found in coastal Evros and Argura; from the Neolithic to Bronze Age transition period in the Ptolemaida basin and in Sitagroi; and beaver remains from the Early Helladic II have been found in northeastern Peloponnese. In the 4th century BC, Aristotle described this species under the name λάταξ/. He wrote that it is wider than the otter, with strong teeth, and at night it often uses these teeth to cut down trees on riverbanks. Ιt's not clear when beavers vanished from Kastoria, but as late as the 18th century they were still hunted for fur. Buffon wrote that they were very rare in Greece at that time. In the 19th century, beavers could still be found in the Alfeios river and in Mesolongi.
The beaver resurgence in Eurasia has brought an increase in human-beaver encounters. In May 2013, a Belarusian fisherman who "tried to grab" a beaver died after it bit him several times, severing an artery in his leg, which caused him to bleed to death.