Eurasian beaver

The Eurasian beaver (Castor fiber) or European beaver is a species of beaver that lives across Eurasia.

In the past, people hunted beavers a lot for their fur and a special substance called castoreum. By the early 1900s, beavers were almost gone, with only about 1,200 left in small groups from France to Mongolia.

Luckily, people worked hard to help the beavers come back. They brought beavers back to many places where they used to live. Today, beavers can be found in Western, Southern, Central and Eastern Europe, Scandinavia, Russia, China, and Mongolia. About half of all Eurasian beavers live in Russia. The Eurasian beaver is now considered safe and is listed as least concern on the IUCN Red List.

Taxonomy

The Eurasian beaver was first described by Carl Linnaeus in 1758. Scientists once thought local beavers were different enough to name separately. But DNA studies show there are only two main groups. One lives in Western and Central Europe, and the other east of the Oder and Vistula rivers. These groups are not different enough to be called separate subspecies.

Description

The Eurasian beaver's fur color changes depending on where it lives. In Belarus, most beavers have a light, chestnut-rust color. In the Sozh River area of Russia, beavers are usually blackish brown, while in the Voronezh Nature Reserve, they can be either brown or blackish-brown.

Eurasian beavers are one of the largest rodents in the world and the largest native to Eurasia. They are about 80 to 100 cm long from head to body, with a tail that measures 25 to 50 cm. They usually weigh between 11 and 30 kg. They are slightly larger and heavier than the North American beaver and are the second heaviest rodent overall, after the capybara.

Eurasian beavers have 48 chromosomes, while North American beavers have 40. These differences mean the two kinds of beavers cannot successfully breed together.

Distribution and habitat

The Eurasian beaver has made a big comeback after almost disappearing. Humans hunted them for their fur and a special secretion from their scent gland. By the early 1900s, there were only about 1,200 beavers left. But thanks to protection and reintroduction programs, their numbers have grown to at least 1.5 million by 2020. Now, beavers can be found across much of Europe, Scandinavia, Russia, and parts of Asia.

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. They have also been seen in Portugal near the Spanish border. Some places where they don’t live include Albania, Kosovo, Northern Macedonia, Greece, and European Turkey, as well as small European countries like Andorra, Monaco, San Marino, and Vatican City.

In Spain, beavers were gone by the 17th century but returned in 2003. By 2020, their population there had grown to over 1,000. In France, beavers were almost gone by the late 1800s, but after protection measures and reintroduction, their population grew to around 14,000 by 2011. In the Netherlands, beavers were gone by 1826 but came back through reintroductions and now number around 3,500. Germany’s beaver population grew to over 40,000 by 2019, and in Poland, there were about 100,000 beavers by 2014.

In Switzerland, beavers were gone by the early 1800s but were brought back between 1956 and 1977. By 2019, there were about 3,500 beavers there. Italy’s beavers returned in 2018 after being absent for nearly 500 years. In Romania, beavers came back in 1998 and have since spread to other rivers. Russia had an estimated 774,600 beavers by 2019.

In Bulgaria, beavers were confirmed to have returned in 2021. Serbia’s beavers, reintroduced in 2004, had spread widely by 2020. In Croatia, beavers were gone by the end of the 19th century but were reintroduced in the late 1990s.

In Denmark, beavers were reintroduced in 1999 and 2009-2011, with populations growing to several hundred by 2019. Norway’s beaver population expanded after protection measures. Sweden’s beavers, reintroduced between 1922 and 1939, numbered around 100,000 by 1995. In Finland, most beavers are North American, but some Eurasian beavers have been reintroduced.

In the United Kingdom, beavers were gone by the 16th century but were successfully reintroduced in Scotland and England in the early 2000s. Scotland’s beaver population grew to over 1,500 by 2022, with potential to reach 10,000 by 2030. England now has over 1,000 beavers, and Wales has small, newly established populations.

In Asia, beavers have been found in Iraq, Iran, Syria, and Turkey, with fossil evidence in Denisova Cave. In China, a few hundred live in the Ulungur River basin near Mongolia.

Behaviour and ecology

Further information: Environmental impacts of beavers

The Eurasian beaver is a keystone species, which means it helps the environment where it lives. By building dams and creating wetlands, beavers make homes for many animals such as the European water vole, Eurasian otter, and Eurasian water shrew. They also help trees and shrubs grow thicker by cutting them down, which gives birds and other animals places to hide. Their dams trap dirt and mud, which makes the water cleaner and helps fish like trout and salmon find more food and shelter. Even bats find it easier to fly through forests that beavers have changed.

Reproduction

Eurasian beavers usually have one group of babies each year. They look for mates for about half a day, between late December and May, with most doing so in January. Beaver couples stay together for many years. After about 107 days, they have between two and six babies, with three being the average. Most beavers start having babies when they are three years old, but some may have babies when they are two.

Diet

Eurasian beavers eat plants found in water and along riverbanks. Their meals include roots, shoots, twigs, leaves, buds, and even trees like willow, aspen, and birch. In farms, they may also eat crops. Their special stomachs help them digest wood from trees. Each day, a beaver eats about 20% of its body weight in food.

Fossil record

Fossils found near Atapuerca show that the Eurasian beaver lived there during the Early Pleistocene. The beaver vanished for a time, even though the area seemed like a good home for them. Later, the beaver came back during the Late Pleistocene and the Holocene periods.

Conservation

See also: Reintroduction of beavers to Europe

The Eurasian beaver once lived all over Europe and Asia. By the early 1900s, hunting had greatly reduced its numbers. Only about 1,200 beavers remained in small groups. Conservation efforts began in 1923 in the Soviet Union, with the creation of the Voronezh Nature Reserve. From 1934 to 1977, beavers from this reserve were moved to many areas from Poland to Mongolia. By 2008, the Eurasian beaver was considered safe because its numbers had grown thanks to conservation programs. Today, the largest groups of beavers live in Europe, where they have been reintroduced in many countries. However, beavers in Asia are still few and scattered and face many challenges.