Beaver

Beavers (genus Castor) are large semiaquatic rodents that live in the Northern Hemisphere. There are two types: the North American beaver (Castor canadensis) and the Eurasian beaver (C. fiber). They are the second-largest living rodents, after capybaras. Beavers have strong bodies with big heads, long chisel-like incisors, brown or gray fur, hand-like front feet, webbed back feet, and flat, scaly tails.

Beavers live in many freshwater habitats such as rivers, streams, lakes, and ponds. They eat tree bark, aquatic plants, grasses, and sedges. Beavers are known for building dams and lodges using tree branches, plants, rocks, and mud. They cut down trees for building materials. These dams slow water flow and create ponds, while lodges are their homes. Their building creates wetlands that help many other animals, so beavers are important to the ecosystem. They live together in monogamous pairs with their young.

In the past, beavers were hunted for their fur, meat, and a special liquid called castoreum. Their fur was very valuable and part of the fur trade. Sadly, overhunting made their numbers very low, but they have recovered since protections began. Today, beavers are doing well and are considered least concern by the IUCN Red List. In many cultures, beavers are symbols of hard work because of their building skills. They are even the national animal of Canada.

Etymology

The word beaver comes from an old Old English word, beofor or befor. This word is related to the German word biber and the Dutch word bever. The original root of the word comes from an ancient Indo-European language and means "brown." Words similar to beaver have inspired many place names in Europe, such as Beverley, Bièvres, and Biberbach. The scientific name for beavers, Castor, comes from the Greek word kástōr, which also means "beaver."

Taxonomy

Carl Linnaeus named the genus Castor. German scientist Heinrich Kuhl named the North American species in 1820. For many years, people thought these were the same animal, but tests showed they are different. The Eurasian beaver has 48 tiny body parts called chromosomes, while the North American beaver has 40.

Today, there are two types of beavers: the North American beaver (Castor canadensis) and the Eurasian beaver (C. fiber). The Eurasian beaver is a bit longer with a pointier skull and lighter fur than the North American beaver.

Characteristics

Beavers are the second-largest living rodents, after capybaras. They can weigh up to 50 kg (110 lb). Their bodies are strong, which helps them pull heavy loads.

Beavers have large teeth that keep growing throughout their lives. They also have special features that help them stay safe and comfortable in water. Their fur is very thick and helps keep them warm and dry. Beavers can swim well and use their webbed hind feet to move through the water. Their tails help them balance, steer while swimming, and store extra food for winter.

Distribution and status

The IUCN Red List says both types of beavers are safe. The North American beaver lives in most of the United States and Canada and also in northern Mexico. This beaver was brought to Finland in 1937 and later spread to northwestern Russia and Tierra del Fuego, Patagonia in 1946. By 2019, North American beavers in Finland were moving closer to where Eurasian beavers live.

In the past, many North American beavers were caught for their fur, and their numbers got very low. But with protections, their numbers grew to about 6–12 million by the late 20th century. The group in Tierra del Fuego is thought to be about 35,000–50,000 as of 2016.

The Eurasian beaver used to live across much of Europe and Asia but was greatly reduced by hunting by the early 1900s. In Europe, small groups remained in places like the Rhône in France and the Elbe in Germany. Thanks to conservation efforts, beavers have returned to many parts of Europe, western Russia, and the Scandinavian Peninsula. Since 2009, beavers have also returned to parts of Great Britain. By 2020, the Eurasian beaver population in Europe was over one million. There are also small groups in Mongolia and northwestern China. Under New Zealand's Hazardous Substances and New Organisms Act 1996, beavers are not allowed in the country.

Ecology

Beavers live in freshwater places like rivers, streams, lakes, and ponds. They love water because it helps them hide from animals that might want to hurt them and makes it easier to carry things. Beavers like calm, slow-moving water and usually pick spots with trees nearby for food and building.

Beavers eat plants, mostly leaves and grasses in spring and summer, and tree bark in fall and winter. They build dams from trees and branches to create ponds where they can live safely. These dams change the land around them, helping create wet areas that many other animals need to survive. Their homes, called lodges, are made from sticks and mud, with special doors underwater to keep them safe.

Behavior

Beavers are mostly active at night and during dawn or dusk, staying in their shelters during the day. In the winter, especially in northern areas, they can stay active for a long time. They don’t hibernate and spend a lot of time in their homes, called lodges.

Beaver families are made up of a male and female pair and their babies. These families can have up to ten members and sometimes need more than one lodge. They stay close by grooming each other and playing, and they rarely fight. When a beaver loses its partner, it will wait for a new one. Babies, called kits, are born in the spring or summer after about three to four months. They can open their eyes soon after birth and have fur right away. The mother takes care of them, while the father looks after the area. Older siblings help too. Kits stay in the lodge for the first couple of months, drinking milk but also eating solid food brought by their parents. As they grow, they start exploring outside and eating on their own. After about a year, young beavers help build with their family. They become fully grown around 1.5 to 3 years old and leave home at two years, though sometimes they stay longer if there isn’t enough food or if there are too many beavers in the area.

Interactions with humans

Beavers can sometimes cause problems by damaging crops, trees, roads, and gardens. They build dams that can flood areas. Very rarely, they might bite a person or pet if they feel threatened, especially if they are sick.

People have many ways to deal with beavers. Special pipes can help manage flooding, and fences can protect trees. Sometimes, beavers need to be moved or their dams removed. Hunting and trapping are also used to control beaver populations. Some places work to include beavers in parks and green spaces.

Beavers have been important for a long time, especially for their fur, which was valuable in trade. They have also been used in stories and symbols, often representing hard work and nature.