[2] Between 1792 and 1997, several Eurasian beaver zoological specimens were described and proposed as subspecies, including:[3] These descriptions were largely based on very small differences in fur colour and cranial morphology, none of which warrant a subspecific distinction.

[10] 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.

The difference in chromosome count makes interspecific breeding unlikely in areas where the two species' ranges overlap.

[citation needed] The Eurasian beaver has shorter shin bones than the North American species and a narrower, less oval-shaped tail, making it less capable of bipedal locomotion.

Beavers build dams that trap sediment, improve water quality, recharge groundwater tables and increase cover and forage for trout and salmon.

[16] Eurasian beavers have one litter per year, coming into oestrus for only 12 to 24 hours, between late December and May, but peaking in January.

[18] 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.

[21][22] 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.

[9] 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.

The only significant areas where it has no known population are the Southern Balkans: Albania, Kosovo, Northern Macedonia, Greece and European Turkey.

[27] In November 2021, a young beaver was photographed for the first time outside the Ebro basin, in the upper Douro river in Soria.

[23] In June 2024, a beaver was sighted at the Tagus river basin near Zorita de los Canes.

[31] 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.

[33] 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.

[52] 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.

By 2020, they had spread 150 km (93 mi) north, west and east, inhabiting rivers in the Sava-Danube system (Drina, Jadar, Great Morava, Tamnava, Tisza, Bega, Timiș, the canal system in Vojvodina), they were found in the capital Belgrade, and had spread to neighbouring Bosnia and Herzegovina.

[61] In Denmark, the beaver appears to have gone extinct 2,000–2,500 years ago, though a small population might have survived into the 1st millennium AD.

[65] By 2019, it was estimated that the Jutland population had increased to 240–270 individuals, and had spread far, from Hanstholm in the north to Varde and Kolding in the south.

[1] The Eurasian beaver was well-established in Great Britain, but was driven extinct there by humans in the 16th century, with the last known historical reference in England in 1526.

[70] In the early 21st century, the beaver became the first mammal to be successfully reintroduced in the United Kingdom, after unofficial and official reintroductions to Scotland and England.

[citation needed] In 2016, the Scottish government declared that the beaver populations in Knapdale and Tayside could remain and naturally expand.

[74] Most sites are recent authorised introductions in large enclosures, but there are established completely free-living populations in the South West.

[75][76] As part of a scientific study, a pair of Eurasian beaver was released in 2011 into a three-hectare fenced enclosure near Dartmoor in southern Devon.

The 13 beaver ponds now in place impacted flooding to the extent of releasing precipitation over days to weeks instead of hours.

[116] In Iraq, Iran, Syria, and Turkey, subfossil evidence of beavers extends down to the floodplains of the Tigris-Euphrates basin, and a carved stone stela dating between 1,000 and 800 BC in the Tell Halaf archaeological site along the Khabur River in northeastern Syria depicts a beaver.

[117] Although accounts of 19th-century European visitors to the Middle East appear to confuse beavers with otters, a 20th-century report of beavers by Hans Kummerlöwe in the Ceyhan River drainage of southern Turkey includes the diagnostic red incisor teeth, flat, scaly tail, and presence of gnawed willow stems.

[118] According to the Encyclopaedia Iranica, early Iranian Avestan and Pahlavi, and later Islamic literature, all had different words for otter and beaver, and castoreum was highly valued in the region.

[119] Johannes Ludwijk Schlimmer, a noted Dutch physician in 19th-century Iran, reported small numbers of beavers below the confluence of the Tigris and the Euphrates, along the bank of the Shatt al-Arab in the provinces of Shushtar and Dezful.

[120] Austen Layard reported finding beavers during his visit to the Kabur River in Syria in the 1850s, but noted they were being rapidly hunted for said castoreum to extirpation.

[124] The Eurasian beaver Castor fiber was once widespread in Europe and Asia but by the beginning of the 20th century both the numbers and range of the species had been drastically diminished, mainly due to hunting.