Everything you need to know about beavers

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Beavers are rodents that are the only modern members of the beaver family. They are divided into two types:

  • common beaver – lives in the zone from the Atlantic coast to the Baikal region and Mongolia;
  • Canadian beaver – lives in North America.

Some zoologists consider the Canadian beaver as a subspecies of the common beaver, but this view is contradicted by a different number of chromosomes (48 for the common beaver and 40 for the Canadian beaver).

In this article we will consider all the most interesting things about the beavers that live in our area. Although the Canadian beaver is both biologically and in lifestyle similar to the common beaver. By the way, the common beaver is also called the river beaver, also the Eurasian beaver or the European beaver.

Everything you need to know about beavers

wikimedia.org

 

Interesting about the appearance of the beaver

The beaver is a large rodent, its length is from 1 to 1,3 meters. It is considered the second largest rodent after the capybara (capybara).

Interestingly, the beaver's tail, which it uses for diving, is not covered with fur, unlike its entire body. To those who watched the animal in the zoo, it might seem that its tail is covered like a fish with scales. In fact, this is bare skin with a kind of "embossing" of keratinized plates. The length of the tail reaches 30 cm.

If someone tells you that beavers are not rodents, fish, you will think: “What kind of nonsense?!”. And you will be absolutely right. However, such a statement (and the proof that beavers are fish was their tail) allowed resourceful monks in past centuries to eat beaver meat during fasting.

Beavers have a beaver stream that emits a strong-smelling secret that serves as a guide to other beavers about the border of the territory of the beaver settlement, it is unique, like fingerprints.

Under water, the nostrils and ear openings close, and the eyes are closed with nictitating membranes. Large incisors are isolated from the oral cavity by special outgrowths of the lips, which allows the beaver to gnaw under water.

Everything you need to know about beavers

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Where does the Eurasian beaver live?

In early historical times, the common beaver was distributed throughout the forest-meadow zone of Europe and Asia, but due to intensive hunting by the beginning of the 20th century, the beaver was practically exterminated in most of its range. The current range of "our" beaver is largely the result of acclimatization and reintroduction efforts.

In Europe, it lives in the Scandinavian countries, the lower reaches of the Rhone River (France), the Elbe (Germany) and Vistula (Poland) river basins, in the forest and partly forest-steppe zones of the European part of Russia, in Belarus, in Ukraine.

In Russia, the beaver is also found in the Northern Trans-Urals, everywhere in the Novosibirsk region. Scattered habitats of the common beaver are found in the upper reaches of the Yenisei, Kuzbass, the Baikal region, in the Khabarovsk Territory, in Kamchatka, in the Kurgan, Omsk and Tomsk regions (10,000 individuals) to the Keti River in the north, in the Altai Territory.

In addition, the common beaver is found in the northern and eastern regions of Kazakhstan, in Mongolia (the Urungu and Bimen rivers) and in Northwestern China.

 

Beaver lifestyle

Beavers prefer to settle along the banks of slowly flowing rivers, ponds and lakes, reservoirs, irrigation canals and quarries. They avoid wide and fast rivers, as well as reservoirs that freeze to the bottom in winter. For beavers, it is important to have woody and shrubby vegetation of soft hardwood along the banks of the reservoir, as well as an abundance of aquatic and coastal herbaceous vegetation that make up their diet.

Beavers are excellent swimmers and divers. Large lungs and liver provide them with such supplies of air and arterial blood that beavers can stay under water for 10-15 minutes, swimming up to 750 meters during this time! At the same time, on land, beavers are rather clumsy.

Beavers live alone or in families. A complete family consists of 5–8 individuals: this is the married couple itself plus young beavers (offspring of the past and current years, since young beavers reach puberty and move out only at 2 years old). A family plot is sometimes occupied by one family for many generations. For example, a small reservoir is occupied either by one family or by a single beaver. But on larger reservoirs, the length of the family plot along the coast is from 0,3 to 3 km.

Beavers rarely move more than 200 meters from the water. The length of the plot depends on the amount of feed. In areas rich in vegetation, the plots may touch and even intersect. Beavers mark the boundaries of their territory with the secret of musky glands – beaver stream.

Beavers communicate with each other with the help of odorous marks, postures, tail blows on the water and screams resembling a whistle. In danger, a swimming beaver slaps its tail loudly on the water and dives. The clap serves as an alarm to all beavers within earshot.

Beavers are active at night and at dusk. In summer, they leave their dwellings at dusk and work until 4-6 in the morning. In autumn, when fodder for the winter begins, the working day lengthens to 10–12 hours. In winter, activity decreases and shifts to daylight hours; at this time of the year, beavers almost do not appear on the surface. At temperatures below -20 °C, animals remain in their homes.

For construction and forage, beavers fell trees, gnaw them at the base, gnaw off branches, then divide the trunk into parts. For example, a beaver fells an aspen with a diameter of 5–7 cm in 5 minutes, and a tree with a diameter of 40 cm fells and butchers overnight, so that by morning only a skinned stump and a bunch of shavings remain at the place of work of the animal.

Everything you need to know about beavers

wikipedia.org

Everything you need to know about beavers

pixabay.com

Everything you need to know about beavers

pixabay.com

Everything you need to know about beavers

pixabay.com

The jaws of beavers act like a saw: in order to fell a tree, a beaver rests its upper incisors against its bark and begins to quickly move its lower jaw from side to side, making 5–6 movements per second. The beaver's incisors are self-sharpening: only their front side is covered with enamel, the back side consists of less hard dentin. When a beaver gnaws on something, the dentin wears down faster than the enamel, so the front edge of the tooth stays sharp all the time.

Beavers eat part of the branches of a fallen tree on the spot, others are demolished and towed or floated along the water to their dwelling or to the construction site of the dam. Every year, walking the same routes for food and building materials, they tread paths on the shore, which are gradually flooded with water – beaver canals. On them they fuse wood fodder. The length of the channel reaches hundreds of meters with a width of 40–50 cm and a depth of up to 1 meter. Beavers always keep the canals clean.

Interesting fact

Everyone knows that beavers build dams. But it is interesting that for them the signal for the construction of the dam is a change in the tone of the murmur of the water, indicating that either the current is too fast, or the seasonal fluctuations in the water level are too great and measures must be taken so that the river flows slowly again.

Everything you need to know about beavers

wikimedia.org

Everything you need to know about beavers

wikipedia.org

 

About the construction of beaver dams

In reservoirs with changing water levels, as well as on small streams and rivers, beaver families build dams. This allows them to raise, maintain and regulate the water level in the reservoir so that the entrances to beaver huts and burrows do not dry up and become accessible to predators.

Dams are built below the beaver town from tree trunks, twigs and brushwood held together with clay, silt, pieces of driftwood and other materials that beavers bring in their teeth or front paws. If the reservoir has a fast current and there are stones at the bottom, they are also used as building material. The weight of stones can sometimes reach 15-18 kg. For more information about the construction of the dam, see the video at the end of our article.

For the construction of the dam, places are chosen where trees grow closer to the edge of the coast. Construction begins with beavers sticking branches and trunks vertically into the bottom, reinforcing the gaps with branches and reeds, filling the voids with silt, clay and stones. As a supporting frame, they often use a tree that has fallen into the river, gradually surrounding it from all sides with building material. Sometimes the branches in beaver dams take root, giving them extra strength.

The usual length of the dam is 20-30 meters, the width at the base is 4-6 meters, at the crest – 1-2 meters. The height of the dam is usually 2 meters, but sometimes it can reach 5 meters. The old dam can easily support the weight of a person.

Interesting fact

The record in the construction of dams belongs, however, not to ordinary, but to Canadian beavers – this dam, built by them in Wood Buffalo National Park (Alberta, Canada), reached a length of 850 meters and was discovered using satellite images in 2007.

Beavers began building it after 1975, as satellite photos provided by NASA World Wind show that the dam did not exist in 1975. The beavers are currently busy expanding the park's other two dams, on either side of the main dam, and if they keep up the current pace of construction for a few more years, the whole thing could turn into one super dam – about a kilometer long.

The shape of the dam depends on the speed of the current – where it is slow, the dam is almost straight, and on fast rivers it is curved in the direction of the current. If the current is very strong, beavers erect small additional dams up the river. A drain is often arranged at one end of the dam so that it does not break through the flood.

On average, it takes a beaver family about a week to build a 10-meter dam. Beavers carefully monitor the safety of the dam and patch it in case of a leak. Sometimes several families are involved in the construction, working "in shifts".

It is still not completely clear how beavers distribute responsibilities among themselves in collective work. They can work either in teams or alone. But both collectives and independent builders act according to a strange universal plan, absolutely precise and thought out to the smallest detail.

Everything you need to know about beavers

wikimedia.org

Everything you need to know about beavers

wikimedia.org

Everything you need to know about beavers

wikipedia.org

Everything you need to know about beavers

wikipedia.org

 

About the upland dwelling

Beavers live in burrows or huts. The entrance to the beaver's dwelling is always under water for safety. Sometimes in the same settlement of beavers there are both huts and burrows. Beavers are very clean, they never litter their homes with leftover food and excrement.

Beavers dig holes in steep and steep banks; they are a complex labyrinth with 4–5 entrances. The walls and ceiling of the burrow are carefully leveled and compacted. The living chamber inside the burrow is arranged at a depth of no more than 1 meter. The living chamber is a little over a meter wide and 40–50 cm high. The floor must be 20 cm above the water level.

Interesting fact

If the water in the river rises, the beaver lifts the floor, scraping the earth from the ceiling. So that the section of the river above the entrance to the hole does not freeze in winter and lock the beaver in the hole, they cover this place with a special canopy.

Huts are built in places where burrowing is impossible – on gently sloping and low marshy shores and on shallows. Huts look like a cone-shaped pile of brushwood up to 1–3 meters high and up to 10–12 meters in diameter. The walls of the hut are carefully coated with silt and clay, so that it turns into a real fortress, impregnable for predators.

Despite popular belief, beavers apply clay with their front paws, not their tail (their tail serves only as a rudder).

Air enters the home through a hole in the ceiling. Inside the hut there are manholes into the water and a platform rising above the water level. With the first frost, the beavers additionally insulate the huts with a new layer of clay. In winter, a positive temperature remains in the huts, the water in the manholes does not freeze, and the beavers have the opportunity to go into the under-ice thickness of the reservoir. In severe frosts, steam rises above the huts, which is a sign of habitability of housing.

Everything you need to know about beavers

pixabay.com

Everything you need to know about beavers

wikimedia.org

 

What are the benefits of beavers?

The appearance of beavers in rivers, and especially the construction of dams by them, has a beneficial effect on the ecological state of aquatic and riverine biotopes. Numerous mollusks and aquatic insects settle in the resulting spill, which in turn attract desmans and waterfowl. Birds on their legs bring fish caviar. Fish, once in favorable conditions, begin to multiply.

Trees felled by beavers serve as food for hares and many ungulates, which gnaw bark from trunks and branches. Butterflies and ants love the juice flowing from undermined trees in spring, followed by birds. Beavers are protected by desmans; muskrats often live in their huts together with their owners.

Dams contribute to the purification of water, reducing its turbidity, insofar as silt is retained in them.

At the same time, beaver dams (or dams) can harm human structures. There are cases when spills arranged by beavers flooded and washed away streets and railway tracks and even caused wrecks.

Everything you need to know about beavers

Canadian beaver | wikimedia.org

 

Some more interesting facts

  • In the city of Bobruisk (Belarus) in 2006, a sculpture of a beaver was opened. A little later, another one.
  • A sculpture of beavers has been unveiled at the Alpine Zoo in Innsbruck, Austria.
  • The sculpture of a beaver is also located above the entrance to the Canadian Parliament building.
  • In April 2016, a beaver attacked a man in Latvia, grabbed his leg, knocked him down and held him on the ground, preventing him from getting up. The victim was saved only with the intervention of the police.
  • On July 1, 2008, the Bank of Russia issued 8 commemorative coins made of precious metals dedicated to the beaver as part of the Let's Save Our World coin series.
  • The image of a beaver can be found on the coats of arms of many municipalities (communities and cities).

 

What a beaver hut looks like in the Slobozhansky National Park (Kharkiv region, Ukraine)

 

Beaver Dam Documentary by National Geographic