Common beaver

The word "beaver" is inherited from the pre-Indo-European language (cf. German Biber ; gem . Bėbros ), formed by incomplete doubling of the name brown. Reconstructed base * bhe-bhru-.

According to linguistic sources of 1961, the word beaver should be used in the meaning of an animal from the order of rodents with valuable fur, and beaver in the meaning of the fur of this animal: beaver collar, clothing on beaver fur ^[3] . However, in colloquial language, the word beaver is universally used as a synonym for the word beaver (like a fox and a fox , a ferret and a polecat ).

According to the 2004 Spelling Dictionary, the pronunciation rate for beavers, beaver (animal; fur) ^[4] .

Beavers first appear in Asia , where their fossilized remains date back to the Eocene . The most famous extinct beavers are the giants of the Pleistocene , the Siberian Trogontherium cuvieri and the North American Castoroides ohioensis . The growth of the latter, judging by the size of the skull, reached 2.75 m, and the mass is 350 kg.

A beaver is a large rodent adapted to a semi-aquatic lifestyle. The length of his body reaches 1–1.3 m, the height in the shoulder is up to 35.5 cm, and the weight is up to 30–32 kg. Sexual dimorphism is weak, females are larger. The beaver has a squat body with short five-fingered limbs; the rear is much stronger than the front. Between the fingers there are swimming membranes, strongly developed on the hind limbs and weakly on the front. The claws on the paws are strong, flattened. The claw of the second finger of the hind limbs is bifurcated - the beaver combes the fur with it. Tail oily, strongly flattened from top to bottom; its length is up to 30 cm, width is 10–13 cm. Hair on the tail is only at its base. Most of it is covered with large horny shields, between which rare, short and stiff hairs grow. A horn keel stretches along the middle line of the tail. The beaver has small eyes; ears are wide and short, barely protruding above the level of the fur. Ear holes and nostrils close under water, eyes are closed by blinking membranes. Molar teeth usually have no roots; weakly isolated roots are formed only in some old individuals. The incisors behind are isolated from the oral cavity by special outgrowths of the lips, which allows the beaver to nibble under water. In the karyotype of an ordinary beaver, there are 48 chromosomes (in the Canadian beaver - 40).

The beaver has beautiful fur, which consists of coarse outer hair and a very thick silky underfur. The color of the fur is from light chestnut to dark brown, sometimes black. The tail and limbs are black. Shedding once a year, at the end of spring, but continues almost until winter. In the anal area are paired glands, wen and the beaver stream itself, which gives off a strongly smelling secret - beaver stream . The prevailing opinion about the use of wen as a lubricant for fur from getting wet is wrong. The secret of wen performs a communicative function, exclusively carrying information about the owner (gender, age). The smell of a beaver stream serves as a guide to other beavers about the border of the beaver settlement, it is unique as fingerprints. The secret of wen, used in conjunction with the jet, allows you to keep the beaver mark longer in the “working” state due to the oily structure, which evaporates much longer than the secret of the beaver stream ^[5] .

In the early historical time, an ordinary beaver was distributed throughout the forest-meadow zone of Europe and Asia , however, due to intensive harvesting, by the beginning of the 20th century, a beaver in almost the entire range was practically extinct. The current range of beaver is for the most part the result of efforts to acclimatize and reintroduce. In Europe, it lives in the Scandinavian countries , the lower Rhone (France), the Elbe basin (Germany), the Vistula basin (Poland), in the forest and partly forest-steppe zones of the European part of Russia , in Belarus, in Ukraine. In Russia, 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 Yenisei , Kuzbass , Pribaikalye , Khabarovsk Territory , Kamchatka , Kurgan, Omsk and Tomsk Regions (ten thousand individuals) to the Keti River in the north, in the Altai Territory. In addition, it is found in the northern and eastern regions of Kazakhstan, in Mongolia (the Urungu and Bimen rivers) and in North-West China ( Xinjiang Uygur Autonomous Region ).

Beavers prefer to settle along the banks of slowly flowing rivers, old ladies , ponds and lakes, reservoirs, irrigation canals and quarries. Avoid wide and fast rivers, as well as reservoirs that freeze to the bottom in winter. For beavers, it is important to have trees and shrubs from soft hardwoods along the shores of the reservoir, as well as an abundance of aquatic and coastal herbaceous vegetation that makes up their diet. Beavers swim and dive superbly. The large lungs and liver provide them with such reserves of air and arterial blood that beavers can remain under water for 10-15 minutes, swimming up to 750 m during this time. On land, beavers are rather awkward.

Beavers live alone or in families. A complete family consists of 5-8 individuals: a married couple and young beavers - offspring of the past and current years. A family site is sometimes engaged in a family for generations. A small pond is occupied by one family or a single beaver. In larger bodies of water, the length of the family plot along the coast ranges from 0.3 to 2.9 km. Beavers are rarely removed from water by more than 200 m. The length of the site depends on the amount of feed. In areas rich in vegetation, sites can touch and even intersect. Beavers mark the borders of their territory with the secret of the musk glands - the beaver stream . Marks are applied to special mounds of mud, silt and branches 30 cm high and up to 1 m wide. Beavers communicate with each other using odorous marks, poses, tail blows on the water and screams resembling a whistle. In danger, a swimming beaver loudly slams its tail in the water and dives. A pop is an alarm for all beavers within earshot.

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

Huts and dams

Beavers live in burrows or huts. The entrance to the beaver’s home is always located underwater for safety. Burrows burrow in steep and steep banks; they are a complex maze with 4-5 inputs. The walls and ceiling of the hole are carefully leveled and rammed. The living chamber inside the hole is located at a depth of not more than 1 m. The width of the living chamber is a little more than a meter, the height is 40-50 centimeters. The floor must be 20 centimeters above the water level. If the water in the river rises, a beaver raises the floor, scraping the ground from the ceiling. So that the section of the river above the entrance to the hole in winter does not freeze and lock animals in the hole, they cover this place with a special canopy. Sometimes the ceiling of a burrow collapses and in its place a solid flooring of twigs and brushwood is arranged, turning the burrow into a transitional type of shelter - a half-shack. In spring, in the high water, beavers build hammocks on the top of bushes from branches and branches with a bed of dry grass.

The huts are built in places where digging holes is impossible - on the gentle and low swampy shores and on the shallows. Beavers rarely begin building new housing before the end of August. The huts look like a cone-shaped pile of brushwood, fastened with silt and earth, up to 1-3 m high and up to 10-12 m 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; air enters through a hole in the ceiling. Despite the widespread belief, beavers apply clay with the help of their forepaws, not the tail (the tail serves solely as a rudder). Inside the hut there are manholes into the water and a platform that rises above the water level. With the first frosts, beavers additionally insulate the huts with a new layer of clay. In winter, a positive temperature is maintained in the huts, the water in the manholes does not freeze, and beavers have the opportunity to go out into the under-ice thickness of the reservoir. In severe frosts over the huts stands steam, which is a sign of habitability of housing. Sometimes in one beaver settlement there are also huts and burrows. Beavers are very clean, never litter their homes with food debris and excrement.

In reservoirs with a changing water level, as well as in shallow streams and rivers, beaver families build dams (dams) . This allows them to raise, maintain and regulate the water level in the reservoir so that the entrances to the huts and burrows are not drained and become accessible to predators. Dams are located below the beaver town of tree trunks, branches and brushwood, held together by clay, silt, pieces of rafting and other materials that beavers bring in their teeth or forepaws. If the body of water has a fast flow 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 the construction of the dam, places where trees grow closer to the edge of the shore are selected. Construction begins with the beavers vertically sticking branches and trunks 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 lining it on all sides with building material. Sometimes branches in beaver dams take root, giving them extra strength. The usual dam length is 20-30 m, the width at the base is 4-6 m, at the crest - 1-2 m; the height can reach 4.8 m, although usually 2 m. The old dam easily withstands the weight of a person. The record in the construction of dams, however, belongs not to ordinary, but to Canadian beavers - the dam built by them on the river. Jefferson ( Montana ), reached a length of 700 m. (In the state of New Hampshire there is a longer dam - 1.2 km.) The shape of the dam depends on the speed of the current - where it is slow, the dam is almost straight; on fast rivers it is curved in the direction of the current. If the current is very strong, beavers erect small additional dams higher 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, a beaver family takes about a week to build a 10 m dam. Beavers carefully monitor the safety of the dam and patch it in case of a leak. Sometimes several families working in shifts participate in the construction.

A great contribution to the study of the behavior of beavers during the construction of dams was made by the Swedish ethologist ( 1971 ) and the French zoologist Richard ( 1967 , 1980 ). It turned out that the main stimulus to the construction is the noise of flowing water. Possessing excellent hearing, beavers accurately determined where the sound changed, which means that there were changes in the structure of the dam. However, they did not even pay attention to the lack of water - in the same way, beavers reacted to the sound of water recorded on a tape recorder . Further experiments showed that sound, apparently, is not the only incentive. So, the beavers laid through the dam were clogged with silt and branches, even if it passed along the bottom and was “inaudible”. At the same time, it remains not entirely clear how beavers distribute responsibilities among themselves in collective work. They can work either as teams, as mentioned above, or alone. But both collectives and independent builders act according to a strange universal plan, absolutely accurate and thought out to the smallest detail.

For the construction and preparation of food, beavers cut down trees, gnawing them at the base, gnawing branches, then divide the trunk into parts. An aspen with a diameter of 5-7 cm beaver fells in 5 minutes; a tree with a diameter of 40 cm fells and cuts during the night, so that by morning at the place of work of the animal there remains only a sanded stump and a bunch of shavings. The trunk of a tree bitten by a beaver takes on the characteristic shape of an hourglass. Beaver gnaws, rising on its hind legs and resting on its tail. Its jaws act like a saw : in order to topple a tree, a beaver rests with its upper incisors on its bark and begins to quickly move its lower jaw from side to side, making 5-6 movements per second. The beaver incisors are self-sharpening: only the front side is enameled, the back consists of less hard dentin . When a beaver chews on something, dentin grinds faster than enamel, so the front edge of the tooth remains sharp all the time.

Beavers eat some of the branches of a fallen tree on the spot, others demolish and tow or float along the water to their dwelling or to the place of construction of the dam. Every year, following the same routes for food and building materials, they trample along the shore paths that are gradually flooded with water - beaver channels. They fuse wood feed along them. The length of the channel reaches hundreds of meters with a width of 40-50 cm and a depth of 1 m. Beavers always keep the channels clean.

The area that was transformed as a result of the activity of beavers settled on it is called a beaver landscape .

Nutrition

Beavers are strictly herbivorous. They feed on the bark and shoots of trees, preferring aspen , willow , poplar and birch , as well as various herbaceous plants ( water lily , small egg , iris , cattail , reed , etc., up to 300 items). The abundance of softwood trees is a necessary condition for their habitat. Hazel , linden , elm , bird cherry and some other trees are of secondary importance in their diet. Alder and oak are not usually eaten, but are used for buildings. Acorns willingly eat. The daily amount of food is up to 20% of the weight of the beaver. Large teeth and a powerful bite allow beavers to easily cope with solid plant foods. Cellulose- rich foods are digested with microflora in the intestinal tract. Typically, a beaver consumes only a few tree species; in order to switch to a new diet, he needs an adaptation period during which microorganisms adapt to a new diet.

In summer, the proportion of grassy feed in the beaver diet increases. In autumn, beavers harvest wood for the winter. Beavers are stockpiled in water, where they retain their nutritional qualities until February. The volume of stocks can be huge: up to 60-70 cubic meters per family. To prevent food from freezing in ice, beavers usually melt it below water level under steep overhanging shores. Thus, even after the pond freezes, food remains accessible to beavers under the ice.

Beavers are monogamous , the female dominates. Offspring are brought once a year. The mating season lasts from mid-January to the end of February; mating occurs in water under ice. Pregnancy lasts 105-107 days. Cubs (1-6 in the brood) will be born in April and May. They are semi-sighted, well pubescent, weighing an average of 0.45 kg. After 1-2 days they can already swim; mother teaches beavers, literally pushing them into the underwater corridor. At the age of 3-4 weeks, the beavers switch to food with leaves and soft stems of herbs, but the mother continues to feed them with milk for up to 3 months. The grown up young growth usually does not leave parents for another 2 years. Only at 2 years young beavers reach puberty and migrate.

In captivity, the beaver lives up to 35 years, in nature 10-17 years.

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 muskrats and waterfowl. Birds on paws bring fish eggs . The fish, being in favorable conditions, begins to breed. Trees felled by beavers serve as food for hares and many ungulates that gnaw bark from trunks and branches. Butterflies and ants love the sap flowing out of thinned trees in spring, followed by birds. Muskrats enjoy protection of beavers; muskrats often live in their huts along with the owners. Dams contribute to the purification of water, reducing its turbidity; silt is delayed in them.

At the same time, beaver dams are capable of harming human buildings. There are known cases when spills arranged by beavers flooded and eroded the streets and the railroad track and even served as the cause of the wrecks ^[6] .

Beavers have long been mined for their beautiful and durable fur. In addition to valuable fur , they give a beaver stream used in perfumes and medicine. Beaver meat is edible; meanwhile, they are natural carriers of salmonellosis pathogens. (It is curious that in the Catholic tradition, beaver meat is considered lean, since a beaver, according to church canons, was considered a fish due to its scaly tail.)

As a result of predatory fishing, an ordinary beaver was on the verge of extinction: by the beginning of the 20th century , only 6-8 isolated populations remained (in the basins of the Rhone , Elbe , Don , Dnieper , in the Northern Trans-Urals, in the upper Yenisei ), with a total of 1,200 animals. To preserve this valuable beast, a number of effective measures for the protection and restoration of numbers have been taken in European countries. They began with a ban on beaver hunting, established in 1845 in Norway . By 1998, the beaver population in Europe and Russia was estimated at 430,000 animals.

The common beaver has the minimum risk status in the IUCN Red List of Threatened Species ^[7] . The West Siberian and Tuvan subspecies of the common beaver are listed in the Red Book of Russia ^{[8] [9]} . The main threat to it at present is reclamation measures , water pollution and the construction of hydroelectric power stations . Detergents that pollute ponds wash away the natural protective layer and degrade the quality of beaver fur.

In places where the number of beavers is very high, they sometimes become pests, because their dams can cause flooding of farmland, settlements and roads. Most often, in such cases, resort to the destruction of dams, but this does not always allow you to achieve the desired result, as beavers very quickly repair damage ^{[10] [11] [12] [13]} .

Beavers in Russia

About a thousand years ago, in Eastern Europe (in Russia , Poland and Lithuania ), organized organized fishing of beavers took place. People engaged in this business ( beaver ), had the exclusive right to hunt ( beaver rutting ) in princely (later - and other) possessions. In fact, these animals were in the semi-domestic position, sometimes whole beaver farms were arranged. Poaching was severely punished. In " The vast Russian truth " it is said: "Even if someone beaver stole, then [pay] 12 hryvnia." Vytautas’s church letter says about beaver fishing:

where the coast of the great prince summits with the boyars, then drive the beavers. And the beaver of the great prince and the boyars and divide the beavers in the old days, and do not hold the nets and the horns and sedges of the boyars, and do not set up knights and cats. And where the princely or boyar coast is special, but the great prince’s coast did not come, then put them on their knees and buckets, and hold dogs, and nets, as I could, so they catch the beaver.

The traces left or beaver fishing tools imposed an obligation on the verv (community) to seek a thief or pay a fine. In those days, beavers were caught in nets and traps. Later, by the 17th century, the number of beavers was already noticeably reduced, and their fishing moved mainly to Siberia . In 1635 it was already forbidden to set traps on beavers. In the XVI Century Trade Book , the usual price for a black beaver is 2 p. Judging by the degree of collection of duties ( 1586 , Novgorod ), a beaver was approximately 1.3 times more valuable than a sable , since for 30 beavers a fee was charged, as for 40 sables. At the end of the reign of Alexei Mikhailovich, a dozen beavers in wholesale cost from 8 to 30 rubles. Their fur was mainly worn on women's hats, necklaces and edges of women's fur coats, but, obviously, was not used for men's fur coats.

By 1917, in Russia, beavers were preserved in 4 isolated territories: in the Dnieper basin (the rivers Berezina , Sozh , Pripyat and Teterev ); in the Don basin along the tributaries of Voronezh ; in the northern Trans-Urals (r. Konda and Sosva ) and in the upper Yenisei along the Azas River. The total number of beavers did not exceed 800-900 heads. Since 1922, hunting for them has been banned everywhere. In 1923, a hunting reserve was organized along the Usman River in the Voronezh Region , and in 1927 it was transformed into the Voronezh State Nature Reserve . Two more reserves were created at the same time: Berezinsky and Kondo-Sosvinsky (founder and first director - Vasily Vasiliev ). Their main task was to protect beavers and restore their numbers. Since 1927, the first attempts to resettle beavers began. From 1927 to 1941, 316 beavers were settled in 12 regions of the European part of the USSR and 2 regions of Western Siberia . From 1946 to 1970, another 12071 beavers were settled in 52 regions, territories and autonomous republics of the RSFSR , in 3 regions of the BSSR , in 8 regions of the USSR , in the Lithuanian , Latvian and Estonian SSRs . As a result of the measures taken, by the end of the 1960s, a beaver in the USSR settled on an area almost equal in area to the range of the 17th century . The increased number of beavers made it possible to organize their fishing again.

• In the city of Bobruisk in 2006, a sculpture of a beaver was discovered. A little later - another.
• The sculpture of beavers is also open at the Alpine Zoo in the city of Innsbruck in Austria.
• In April 2016, in Latvia, a beaver attacked a man, grabbed his leg, knocked him down and held him on the ground, preventing him from getting up. It was possible to save the victim only with the intervention of the police. ^[fourteen]

Beaver Hut in Slobozhansky National Park, Ukraine

The image of a beaver can be found on the arms of many municipalities (communities and cities).

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  Coat of arms of Omli , Norway

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  Coat of arms of Beverne , Germany

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  Coat of arms of Bieberstein , Switzerland

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  Coat of arms of Donskoy , Russia

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  Coat of arms of Bobrov , Russia

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  Coat of arms of Lomza , Poland

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  Flag of Oregon , USA

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  Coat of Arms of Manitoba , Canada

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  Coat of arms of Iskitim , Novosibirsk region , Russia

On July 1, 2008, the Bank of Russia , in the framework of the “Save Our World” series of coins, issued 8 commemorative coins made of precious metals dedicated to beaver (only the reverse are shown):

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  3 rubles from silver

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  25 rubles from silver

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  50 rubles from gold

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  100 rubles from gold

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  100 rubles from gold (rough coinage)

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  200 rubles from gold

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  100 rubles from silver

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  10 000 rubles from gold

• Skalon V.N. River beavers of North Asia / Moscow Society of Naturalists . - M .: Publishing House of Moscow Institute of Applied Mathematics, 1951. - 208 p. - 2000 copies.
• Dezhkin V.V. , Dyakov Yu.V. , Safonov V.G. Beaver. - M .: Agropromizdat , 1986. - 256, [24] p. - 6500 copies.
• Bondarev L.G. Beaver Empire // Geography. 1999. No. 13. S. 10-11.

• Vertebrates of Russia: European Beaver
• Beavers in Chelyabinsk
• An unexpected meeting with a beaver in the very center of Moscow
• Castor fiber L. - European Beaver