The beaver is the largest rodent (body length 75-100 cm) with a flattened spade-shaped tail covered with horny scales. The weight of an adult beaver is about 18 kg, and the maximum reaches 54 kg. Males and females are indistinguishable in weight. The color of the fur is variable: from light brown to dark brown and almost black. The guard hairs are shiny, long, coarse, the underfur is very thick and soft. The front legs are shorter than the hind legs, with strong claws, well adapted for digging, the hind legs have a large foot and a leathery membrane between the toes. The auditory openings and nostrils close when immersed in water. The eyes have a transparent nictitating membrane that protects them from exposure to water when diving. The upper lip is forked and the lips can close behind the incisors, allowing the beaver to chew through plants underwater.
The river beaver used to widely inhabit the water bodies of the forest belt of Russia, including the territory of the northwestern regions, but by the end of the 19th century it was severely exterminated and remained in several small isolated foci. In the North-West of the country it has completely disappeared.
After the October Revolution, in order to increase the number of the species, several reserves were created, where the number of beavers increased so much that opportunities were created for their resettlement in other areas.
As a result of extensive work carried out in our country to resettle the beaver, a significant part of the reservoirs where it lived in the old days is now inhabited by it.
In the northwestern regions, beaver reacclimatization proceeded as follows. Experimental releases of small batches of river beaver (6-10 heads), carried out in 1934-1937. in the Tersky district of the Murmansk region, proved the possibility of continuing and expanding this work. Beavers brought to the Arctic Circle from the Voronezh region quickly adapted to new conditions despite the sharp differences in river regimes and food composition. Their numbers increased, and 10 years later, by 1947, the number of beavers on the territory of the Lapland Nature Reserve increased 7 times, their number amounted to slightly more than 100 heads (Nasimovich, 1948). In subsequent years, resettlement continued, but the lack of regulated trapping of animals in long-term settlement areas led to the depletion of winter food supplies and slowed down the rate of reproduction. During this period, beavers built dams and laid canals to improve their living conditions and better access to food. There have been repeated attempts by beavers to build dams even on such fast rivers as the Chuna, Kupes, and Tashkim (Nasimovich and Semenov-Tyan-Shansky, 1959, German, 1960).
Beavers released in the river basin Deer also populated areas of the coast suitable for habitation and their numbers increased. In subsequent years, as the supply of winter food was depleted, and in the absence of catching animals, beavers were forced to migrate to new places, often far away, and some of the animals died. As a result of the depletion of woody food reserves along the banks (mainly birch), by 1954 there were only a few settlements left here.
The release of a large batch (34 individuals), made in 1957 in the Lovozero region in the river basin. Ponoy, significantly expanded the range of the beaver in the Murmansk region (Table 14).
TABLE 14
Release of beavers in the North-West in 1951-1964.
| Regions | Years | Total | ||||||||||
| 1951 | 1952 | 1956 | 1957 | 1958 | 1959 | 1960 | 1961 | 1962 | 1963 | 1964 | ||
| Leningradskaya | — | 27 | 22 | 70 | 30 | 40 | 66 | 32 | — | — | 32 | 319 |
| Murmansk | — |
— | — | 34 | — | — | — | — | — | — | — | 34 |
| Novgorodskaya | — | 18 | — | — | — | — | 57 | — | 32 | 33 | — | 140 |
| Pskovskaya | 28 | 26 | — | — | — | — | 33 | 22 | 34 | 42 | 32 | 215 |
| Karelian ASSR | — | — | — | — | — | — | — | — | — | — | 6-1 | 7 |
| Total | 26 | 71 | 22 | 104 | 30 | 40 | 156 | 54 | 66 | 75 | 71 | 715 |
In the conditions of the Murmansk region, where in most water bodies food supplies are relatively limited and their renewal is slow, it is necessary to carry out systematic selective catches of animals. A long stay of a large settlement in one place leads to depletion of food supplies, degradation of the settlement itself and the needless death of animals. There is no reason to expect prospects for the creation of large beaver colonies in the region.
Beavers were not released on the territory of the Karelian Autonomous Soviet Socialist Republic until 1964. Beavers began to appear here in 1953 from the border areas of Finland along adjacent reservoirs, first in the Sortavala, and later in the Segezha and Suojärvi regions. Gradually spreading further and further to the east, they noticeably expanded their range, despite the fact that in a number of reservoirs the supplies of winter food were limited.
Beaver settlements in Karelia are in most cases confined to reservoirs with swampy, often unstable banks, often flooded by dams built by beavers. These circumstances create significant difficulties in catching them.
In 1964, in the Suoyarvi region, six beavers were captured for release into the river basin. Shui, Prionezhsky district. It was established that these animals are representatives of the Canadian species. In 1965, the number of beavers in the western regions of the republic amounted to 200 heads.
The presence of the Canadian beaver species in the republic makes it possible to use its reserves for breeding purposes.
In the Leningrad region, the first batch of beavers delivered from the Voronezh Nature Reserve (27 heads) was released in 1952 on the river. Dolgaya (left tributary of the Luga River) in the Kingisepp district (see Table 14). Subsequent releases were carried out from 1956 to 1964. During this time, another 292 beavers were brought in and released in 21 rivers of the Gatchina, Tosnensky, Kirishi, Volkhovsky, Lodeynopolsky, Podporozhsky, Vsevolzhsky and Priozersky districts. In addition, since 1958, beavers began to appear in the Vyborg region, moving from Finland along the river system. Vuoksa and other border rivers. As a result of releases and natural settlement, beavers are currently found in 13 districts in the river basins. Luga, Neva, Volkhov, Voronezhka, Pasha, Syasi, Svir and Vuoksa.
In the Leningrad region, as a result of beaver resettlement work, several isolated foci have now formed. Of these, the oldest exist in the river basin. Lugi, on the river Dolgaya and its tributaries in the Kingisepp, Slantsevsky and Luga regions and on the river. The lizard and its tributaries in the Gatchina and Luga regions.
On the river Long beavers were released in 1952, 4 km above the village of Paozerye, where the river branches into three channels, connected by branches. The banks of the channels and branches are covered with deciduous forest, willow thickets, and various herbaceous vegetation.
Having found favorable living conditions here, the beavers first settled near the release site, and then, as they reproduced, they also developed tributaries of the river. Dolgoy, Samru and Zuevik.
The highest density of beaver settlements is on the river. Dolgy is observed in the branched part of the river and in the area located higher (the Khaluya tract).
The abundance of summer and winter food and good protective conditions create favorable habitat opportunities, which is why beaver settlements are located here at a distance of 0.3 to 0.5 km from one another. Thus, on the Khaluya section of the coastline less than 5 km long there are six settlements, on Anokha on 2 km - four and on Glukhoy on an area less than 1.5 km - three settlements. The same close proximity of settlements is observed in a number of other sections of the river.
On the river In the lizard, where beavers were released in 1956, living conditions turned out to be less favorable than on the river. Long, however, here too they populated all areas suitable for their habitat. Population density of the river banks Lizards below - from 1 to 2 km between settlements. On a tributary of the Yashchera, the Zhelezenka River, where conditions are favorable, two settlements are located less than 0.5 km from one another. As the Lizard and its tributaries settled, some of the animals entered the river. Lugu and settled in its nearby tributaries (Dymenka, Kemka, etc.).
On the Dolgaya and Yashcher rivers, in the first years after graduation, the growth in the number of individual families and the formation of new settlements was very noticeable. Later (in the next 5-8 years) the population growth began to slow down. Newly formed couples sometimes had to go several kilometers in search of a better site. Such changes are natural and are observed in many regions of the country.
Currently, in the Luga basin, the previously isolated foci on Dolgaya and Yashchera have almost merged due to the natural spread of beavers; the total number of animals here is at least 300 individuals.
In the eastern and northeastern regions of the Leningrad region, beavers were resettled in 1957-1961. The animals also took root everywhere, and in subsequent years, multiplying, settled along numerous tributaries of the Volkhov, Svir, Voronezhka, Syasi and Neva river basins. Some of the animals went to the Novgorod region along adjacent reservoirs.
One of the largest beaver foci in this part of the region is located on numerous tributaries of the pp. Pasha (Svir basin), Bolshaya Rybezhka, Syaznega, Kandega, Vikhmesi, Shizhna, Pinezhka, Medvezhka and their tributaries. From the original release sites, the beavers settled tens of kilometers into the upper tributaries of the Pasha. The distance between settlements ranges from 0.3 to 0.8 km or more, with gaps of up to several kilometers.
In the Svir basin there are also colonies of beavers in the tributaries of the river. Oyat on the rivers Savinka, Shapsha and some other rivers, as well as in the system of the Verkhne-Svirsky reservoir on the rivers: Svyatukha, Ostrechinka, Shamenka and others.
The total number of beavers inhabiting the Svir basin is about 300 animals.
A small focus (about 50 specimens) exists on the river. Voronezhka and its tributaries (Lake Ladoga basin).
Beavers settled widely in the river basin. Syasi, in the Valgomka rivers and its tributaries (Massalga, Halmachi), in the tributaries of the river. Lynny (Pelona and Shiritsa), in the rivers Kusega, Vale and their tributaries and in a number of other small rivers and oxbow rivers. Syasi. Living conditions in the listed foci are similar to those in the river basin. Sviri. In total, there are about 120 beavers in the Syasi basin.
In the Volkhov basin, beavers were released somewhat later (in the fall of 1960). In the tributaries of this river, beavers live in the upper reaches of the river. Pchevzhi, from where some of the animals descended into the Volkhov and, having climbed up it, settled in the tributaries of the river. Oskuya and on some other rivers in the Novgorod region. In addition, in the Volkhov basin there is a small focus in the upper reaches of the river. Tigoda and its tributaries.
In the Neva basin, beavers were released in 1960 into tributaries of the upper reaches of the river. Tosno: rivers Sunyu, Serdtse, Eglinka (Lisinsky hunting reserve). Three additional adult beavers were also released there in 1964. Due to the drought that occurred after the release, the living conditions on these small rivers turned out to be unfavorable, so most of the animals descended into the river. Tosnu and settled along its banks.
The last releases of beavers into the region's water bodies were carried out in the fall of 1964 in the following rivers: Petlyanka (Vyborg region), Vyut and Chernaya (Lake Ladoga basin - Priozersky and Vsevolzhsky regions).
In the Vyborg region, as noted above, since 1958, beavers began to appear, moving along adjacent reservoirs from Finland. They settled along the Bolshoye and Maly Mezhgorny, Bobrovoy, M. Pamyatny lakes, along the river. Dymovka and its tributaries and some others. Living conditions in these reservoirs are not always sufficiently favorable both in terms of food reserves and water regime. The animals improve their living conditions by building dams and continue to settle to the south. In the population that came from Finland, it is possible to meet animals of another species—the Canadian beaver, which is of particular interest for resettlement purposes.
The distribution of beaver settlements across the main river basins of the region and the approximate number of animals are presented in Table. 15.
TABLE 15
Distribution and abundance of river beaver in the main river basins of the Leningrad region in 1966.
| Rivers | Number of settlements | Number (heads) | Possible catch (heads) |
| Meadows | 60 | 280—300 | 28 |
| Neva | 12—14 | 50—60 | 5 |
| Volkhov | 19—21 | 82—90 | 8—10 |
| Sitting | 24—26 | 110—120 | 10 |
| Voronezhka | 10-12 | 45—50 | 5 |
| Svir | 58—62 | 280-300 | 28 |
| Vuoksa | 20—22 | 120—130 | 10-12 |
| Total | 203—217 | 967—1050 | 94-98 |
Many reservoirs have had beaver stocks at commercial density for several years now.
The commercial capture of 50 beavers for skins was first permitted in 1966/67. However, due to the lack of experience in trapping in winter conditions and the early melting of the ice, only 12 beavers were caught. The fishing was carried out by teams of hunters with special permits from the State Hunting Inspectorate.
In the Pskov region, the first beaver releases were made in 1951 and 1952. (Chernaya river) in the amount of 36 individuals. In 1952, beavers were also released in the upper reaches of the river. Great (16 individuals). As a result of these releases. Two outbreaks arose: the northern one, within the Pskov and Gdovsky districts, and the southern one, in the Pustoshkinsky district.
The northern focus includes the river basins. Black and Bile. The valleys of these rivers are vast swampy lowlands adjacent to the eastern coast of Lakes Pskov and Lake Peipsi. Favorable lands along the river. The Chernaya and its main tributaries contributed to the rapid increase in the number of beavers and their spread into adjacent water bodies. After 5-6 years, beavers began to appear along the river. Zhelche and its tributaries, and then other rivers flowing into Lake Pskov. The highest density of settlements is observed in the release area, on the river. Chernaya and its tributary river. Volosne. Here, settlements are often located at a distance of 0.3-0.5 km from one another. In such places, the river banks are swampy, covered with willows, alders and wetland vegetation. Beavers have laid paths and underground passages deep into the shores. Beavers find here an abundance of food and good protective conditions hundreds of meters from the river bank. Since its release in 1960, the beaver population here has increased more than 8 times. In the river basin Chernaya there were up to 45 settlements with a total population of 260 beavers, and in the river basin. Zhelchi - up to 17 settlements (70 beavers). The distribution of beaver settlements in the basin of the Chernaya and Zhelchi rivers in 1960 is presented in Table. 16.
The southern center of beavers, located within Pustoshkinsky and adjacent areas, occupies numerous lakes and rivers belonging to the basins of the Velikaya, Lovat and Western Dvina rivers. Along the valleys of rivers and lakes, small-leaved, predominantly birch forests with an admixture of broad-leaved species and, in some places, conifers are widespread. Coastal and aquatic herbaceous vegetation is well developed here.
TABLE 16
Distribution of beaver settlements in the basin pp. Chernaya and Zhelchi, Pskov region
| Rivers and their tributaries | Number of settlements | Total number (heads) |
| Black | 18 | 110 |
| Tributaries: | ||
| Bushevica | 2 | 12-14 |
| Volosnya | 14 | 80—85 |
| Zvanka | 3 | 10 |
| Lochkina | 4 | 20—25 |
| Plotishchenka | 1 | 8—10 |
| Tuchenka | 1 | 4 |
| Sashkino | 2 | 6-8 |
| Bile | 2 | 11 |
| Tributaries: | ||
| Branca | 1 | 2 |
| Top squirrel | 10 | 35 |
| Upper tributaries of the Zhelchi | 4 | 12—14 |
| Total | 62 | 310—328 |
Most of the beaver settlements are located in the river basin. Great, namely: in the upper reaches of the lake. It is also likely to occur in flowing lakes and lakes adjacent to the river. Since 1957, beavers began to appear outside the Velikaya basin (Lake Asho). The distribution of settlements in the southern focus by the fall of 1960 is presented in Table. 17.
TABLE 17
Distribution of beaver settlements in the southern part of the Pskov region in 1960.
| Rivers and lakes | Number of settlements | Total number |
| R. Great | 10 | 46—50 |
| Lakes: | ||
| Probably | 7 | 30—32 |
| Lukoe | 1 | 2—4 |
| Scientist | 3 | 11—14 |
| Coniferous | 3 | 11-14 |
| Somino | 2 | 6—8 |
| Black | 1 | 10 |
| Guzenets | 1 | 4 |
| Asho, Reble | 8 | 24—30 |
| Total | 36 | 144—166 |
The successful re-acclimatization of the beaver in the Pskov region made it possible in 1960 for the first time in the North-West to begin capturing animals for intra-regional resettlement. During the period from 1960 to 1963, 76 beavers were captured in the northern regions and 55 in the southern regions. They were released into the rivers and lakes of Velikoluksky, Loknyansky, Novorzhevsky, Novosokolnichesky, Plyussky, Pustoshkinsky, Porkhovsky and Sebezhsky districts.
The importation of beavers in 1964 from the Byelorussian SSR was not necessary, since by that time almost all water bodies of the region suitable for beaver habitation were inhabited.
The distribution of settlements and the number of beavers in the Pskov region by 1967 are given in Table. 18.
As can be seen from table. 18, in the territory of the Pskov region by 1967, 209 settlements with a total population of over 1000 beavers were registered.
Commercial catching of beavers for their skins began in 1966, when 35 beavers were caught in the northern part of the region and 16 in the southern part.
The first release of beavers in the Novgorod region was made in 1952 in the river. Chernaya, Malovishersky district (18 individuals). The reserve organized here contributed to the rapid growth in the number and distribution of beavers along the river and adjacent reservoirs. Subsequent releases took place in 1960 in the Borovichi district on the river. Veregzhe and Udine (Msta River basin, 57 beavers), and then in 1962 and 1963. in the Valdai region in the tributaries of the river. Valdayki (65 beavers).
As a result of releases and natural settlement, beavers are currently found in eight districts in the basins of Msta, Volkhov, Valdaika, Shelon and others.
In the Malovishera region, as a result of the settlement of the Chernaya River and the resettlement of beavers in adjacent reservoirs, the total number of animals by 1962 increased approximately 7 times. In certain sections of the river. Black settlements were located from each other at a distance of up to 0.4 km. To improve their living conditions, beavers built a system of dams on the river and flooded large sections of the banks. By 1966, the total number of this colony was determined to be 180 animals.
TABLE 18
Distribution and number of beavers along the main rivers of the Pskov region in 1967.
| Rivers and their basins | Number of settlements | Total number (heads) | Districts |
| Black | 85 | 370-410 | Gdovsky and Pskovsky |
| Bile | 32 | 156—170 | Gdovsky |
| Tolba | 4 | 18—22 | Pskovsky and Strugo-Krasnensky |
| Pskov | 13 | 58—70 | |
| Plussa | 9 | 42-50 | Plyussky |
| Pools: | |||
| Upper reaches of the Veli- | 25 | 107—124 | Pustoshkinsky Sebezhsky |
| Middle reaches of the Great | 4 | 20—22 | Novorzhevsky |
| Uschi | 5 | 26—30 | Pustoshkinsky |
| Western Dvina | 12 | 65-85 | Nevelsky |
| » | |||
| Sebezhsky | |||
| Black | 3 | 15—17 | » |
| Shaloni | 14 | 62—70 | Dedovichsky Porkhovsky |
| Lockney and Lovati | 3 | 14 | Loknyansky Velikoluksky |
| Total | 209 | 954—1084 | |
In the Borovichi region, beavers have also successfully taken root, and their numbers are increasing. In 1966, 53 settlements with a population of about 280 beavers were discovered in the region. In the Valdai region, despite a number of unfavorable changes in living conditions due to artificial disturbance of the water regime, the number of beavers is also increasing and in 1966 was close to 140 individuals. The population density of individual reservoirs necessitates the capture of animals.
In the Chudovsky district, in the river basin. Volkhov, beavers entered from the Leningrad region. Here, by 1966, there were about 20 settlements with a population of over 100 animals. In recent years, beavers have also spread throughout the river basin. Sheloni from the territory of the Pskov region.
In 1967, for the first time in the region, 12 beavers were caught in the reservoirs of the Borovichi district to populate the rivers of the Novgorod region.
The distribution of settlements across the main basins of the region and their approximate numbers are presented in Table. 19.
TABLE 19
Distribution and number of beavers in the main basins of the Novgorod region, 1966.
| Regions and rivers | Number of settlements | Beaver population | Possible catch (heads) |
| Malovishersky, Msta |
52 | 240—260 | 25 |
| Borovichsky, Msta | 53 | 260—280 | 25 |
| Valdaisky, Valdayka | 29 | 130—150 | 15 |
| Chudovsky, Volkhov | 20 | 100—110 | 10 |
| Total | 154 | 730—800 | 75 |
The prospects for the further settlement of beavers in the region are favorable.
Summarizing what has been said about the reacclimatization of the beaver in the North-West, it should be concluded that, in general, it is happening very successfully and the beaver is gradually again becoming one of the commercial species of this territory.
The biology of the beaver is briefly summarized as follows. The beaver leads a semi-aquatic lifestyle and inhabits the banks of forest rivers, streams, lakes, oxbow lakes, canals, ponds and peat quarries. It prefers bodies of water with slow currents, but sometimes settles on large navigable rivers.
A necessary condition for the life of the animal is the presence of deciduous trees and shrubs, aquatic and terrestrial herbaceous vegetation along the banks of the reservoir. For the beaver to live normally, reservoirs must be of sufficient depth in the coastal zone, not freeze in winter and not dry out in summer. Prolonged spring floods are unfavorable, causing the death of young animals and separation of family members. Late autumn and winter floods are also destructive.
Beavers live in families, occupying a certain section of a river or lake. They dig their burrows in the banks, making their entrance from the water. If the banks are high enough, then the nesting chamber, located at some distance from the water's edge, is located above its level. On reservoirs with low banks, beavers build lodges, using branches, rotted herbaceous plants and silt to build them. Huts reach heights
1.5-3 m and have a diameter at the base from 3 to 12 m. Living chambers are arranged inside the hut, usually there are several of them, at different levels. Sometimes the huts are surrounded by a canal filled with water. Beavers dig underground passages along the banks, lay channels 60-80 cm wide in swampy banks, and on dense banks - paths leading to areas with rich food reserves.
On reservoirs that are subject to drying out in the summer, beavers build dams below their homes that block the river bed. The length of the dams sometimes reaches 100 m or more. The water raised by the dam floods the flat parts of the banks and gives the animals access to new feeding areas.
Beavers live in a chosen place for several years and leave it either when food is depleted, or when there is a sharp deterioration in the water regime, for example, severe shallowing due to drought or flooding of land during the construction of dams for hydroelectric power stations, etc. Often, after a number of years, they return to the abandoned place. plot.
A beaver family usually consists of parents, young of the year and last year's litter, a total of six to eight animals. Sometimes the family grows with young two- and three-year-olds.
By autumn, all family members who had previously lived separately gather at the main home. During this period, traces of animal activity are especially noticeable in the area of the settlement. They repair huts and prepare food for the winter; Freshly cut trees and shrubs are often found along the banks of the reservoir. The trunks and branches of trees and shrubs, divided into parts, are floated to the hut or to the hole and flooded in heaps at the entrance. These reserves reach 10–30 loose cubic meters or more.
In winter, beavers are active. In cold weather, they rarely appear on the surface, and their activities take place under the ice. Only when there is a lack of stored food or when it spoils at the end of winter, as well as in the absence of aquatic plants in the settlement area, do they come to the surface or make passages in the snow to places with food reserves.
In the spring, the beaver family splits up. The female and the young usually remain in the main nest. The remaining members of the family settle in the neighborhood, and the two- to three-year-old beavers separate and some of them join in mating pairs.
Beavers lead a crepuscular and nocturnal lifestyle, but where they are not disturbed, they often appear on the surface during the daytime. Among the external senses, beavers have well-developed hearing and smell. When diving, a beaver can stay in the water for up to 15 minutes.
The main food of beavers is the bark and shoots of deciduous trees, shrubs and grasses. Among tree and shrub species they prefer aspen, various types of willows, birch, and poplar; Less commonly eaten are rowan, bird cherry, hazel, buckthorn, alder, linden and some others. Of the herbs, various types of sedges, water lilies, egg capsules, reeds, cattails, watches, reeds, arrowheads, nettles, marigolds, meadowsweet, sorrel, arrowhead, etc. are most often eaten.
The diet varies somewhat depending on the season. In early spring, beavers eat mainly fresh green bark and branches, later - leaves and young shoots of trees and shrubs, as well as stems, flowers and other parts of aquatic and coastal herbaceous plants. From September, animals begin to eat bark, branches of trees and shrubs, as well as aquatic and coastal grasses again. After water bodies freeze, coastal herbaceous vegetation falls out of the diet, and aquatic vegetation, if present and accessible, is eaten throughout the winter. The beaver is capable of chewing plant stems underwater, while its lips close behind the teeth, preventing water from entering the mouth.
Beavers reach sexual maturity at three years of age. The estrus period is quite extended, being confined to the end of winter - early spring. Mating occurs in water. Pregnancy lasts 103-107 days. In May-June, the female will give birth to one to five (usually 2-3) cubs. They are born sighted, covered with soft fluffy hair. Milk feeding lasts about 2 months. At the age of one month, beavers already eat green food.
The increase in the beaver population in different reservoirs is not the same. It depends on living conditions, age and composition of beaver settlements. Typically, in the first years after settling a reservoir, the population increases faster, and then, as food supplies decrease, more slowly.
Beavers moult in the spring. Hair regrowth occurs gradually during the summer-autumn period and ends by winter. Fur becomes a day off from December to March.
The enemies of adult beavers are the wolf, lynx and bear; For young people, in addition, foxes, raccoon dogs, otters, minks, large owls, goshawks, ospreys, large pikes and catfishes are dangerous.
Beavers are susceptible to various diseases. There are known cases of their death from paratyphoid fever, pasteurellosis, hemorrhagic septicemia, tularemia, and tuberculosis. However, widespread infectious diseases are rare. There is a high infestation of beavers with worms, often causing various diseases, especially stichorchiasis and grass sosiosis. In dry years, intestinal diseases become more widespread.
The beaver's competitors for food include elk, hares, muskrats and mouse-like rodents. They often eat the bark and branches of trees felled by beavers. Burrows and abandoned beaver dwellings are sometimes inhabited by otter, mink, muskrat, raccoon dog, fox and other animals.
The damage caused by beavers to forestry is small, since they eat mainly trees of low-value species. When beavers build dams, grasslands and forest areas are sometimes flooded.
Literary data and a study of the living conditions of beavers in a number of reservoirs in the Leningrad, Pskov and Novgorod regions show that a colony of beavers, even in a reservoir with good living conditions, having colonized all suitable banks, is subsequently partially evicted. In the remaining settlements, the population growth seems to stop and the colony begins to degrade; The reasons for this are a number of factors, namely: when a reservoir is densely populated, difficulties are created for the settlement of young beavers that form mating pairs. Due to the lack of suitable habitat, hostile relations between beavers of different families are intensifying, and in a number of settlements, due to the long stay of a large number of beavers, winter food supplies are depleted. In addition, the high density of animals contributes to the spread of various diseases; finally, even a reflex delay in reproduction is possible in mature females that are part of large families.
To maintain a constant maximum number of beaver populations, it is necessary to carry out systematic trapping of animals, avoiding their excessive crowding. Catching part of the animals or entire families in water bodies with increased density creates more favorable conditions for the existence of the remaining families and will contribute to normal growth in the population. First of all, it is necessary to catch lonely animals and weak families in the worst lands and on reservoirs where settlements are crowded.
Fishing should be carried out by specially created teams (2-3 people) under the control of the State Hunting Inspectorate. Catching is carried out using large traps.
Beaver pelts reach better quality by the end of winter, so it is more advisable to hunt during the winter months (December - February). The beaver produces a pelt of excellent quality and wearability; The best castor hats are made from beaver fluff; “beaver stream” (castoreum) is used in the perfume industry and is barely inferior in cost to its skin. Beaver meat is also edible.
When it comes to talking about beavers, a river miracle with huge, yellow, sharp teeth that can chew through anything immediately appears before your eyes. These animals are indeed very toothy, but in nature they bring great benefits precisely thanks to their tireless jaws. Everyone knows that the beaver is a born builder. He is an example of perseverance and hard work. It was from these workers that people learned experience that was useful in the construction of dams. Sometimes there is something to learn from our smaller brothers. How does a beaver live, what does it eat, and how does it build its unique structures? You will learn about all this by reading the article.
The largest rodent
Nowadays, there are two species in nature and the European one. The differences between them are small, except that the European one is slightly smaller than the Canadian one. A long time ago, about 5 million years ago, beavers could measure their strength even with the owner of the forest himself - the bear. The huge ancestors of today's rodents have gone extinct, and today's dam builders are much smaller in size than their great-grandfathers.
An adult male beaver weighs approximately 20-25 kg, some bogatyrs reach a weight of 45 kg, and their length reaches 1.2 meters. The delightful tail occupies 15-20 cm, its width is almost equal to its length. This tail also plays an important role as a keel - with its help, the furry swimmer regulates the depth of immersion in the water. The beaver's completely transparent eyelids allow it to see everything underwater and navigate perfectly there.
There is something else interesting in the appearance of rodents: the claw on the thumb is split into two halves - this is a gift from nature so that the animals have the opportunity to comb their fur. Continuing the conversation about limbs, I would like to note that they help beavers swim well. The hind legs are webbed, the same kind of membranes that ducks have. Thanks to them, swimmers can reach speeds of up to 10 km/h. The front paws are relatively small, without membranes, and equipped with impressive, powerful claws that can easily dig the ground. The front paws also act as hands - animals use them to carry clay and branches.
Beautiful thick fur and a thick layer of fat under the skin protect beavers from the cold. The animals carefully look after their fur coat, combing it with a natural comb. Thanks to the oily liquid secreted by special glands, this wonderful fur does not get wet.
Animals' teeth grow throughout their lives, and if they are not regularly ground down on wood, they will reach unprecedented sizes.
The life of beavers in nature is full of dangers. Its duration is on average 13-15 years. In captivity they live 2-3 times longer.
All those animals that neighbor beavers entrust them with the mission of preserving and, if necessary, saving water and adjacent forest lands. It turns out that with their work, furry builders care not only about their well-being - the peace of their neighbors also depends on them.
The sound of flowing water awakens the beavers' passion for construction, and they begin to act. They can build for days - day and night; it is impossible to find more hardworking workers. Beavers begin to develop new aquatic territory according to a plan developed over the years:
- A dam is being built that will turn the stream into a cozy and quiet pond.
- A system of canals is created to expand the domain.
- A huge storeroom is being built.
- A huge, multi-room house more than 1 meter high is being built. The walls of the house are built half a meter thick.
After just one week, the house is ready, the entrances are under water to protect the home from enemies. When a beaver works at a “sawmill”, harvesting wood, he is at risk. A tree can fall and crush a beaver, so only one goes for building materials, and at the same time for food, the rest of the family members are busy with other household chores. Good for these lumberjacks! After all, what does a beaver eat? Yes, with what they build their dams from. It is important to obtain building material, but food supplies for a family of rodents also need to be very large.
Faithful spouses and caring parents
Loyalty and devotion reign in the family of furry rodents. They do everything together throughout their lives, wisely distributing work among all family members. Young people can live with their parents for up to two years, after which the children must go to build their own home, trying to find a mate during their wanderings.
A mother beaver gives birth to a litter of 3 to 4 cubs weighing 0.5 kg each. Babies are born complete copies of their parents, only small. They are already wearing coats with big teeth and adorable tails. After two weeks, future lumberjacks are already gnawing on solid food. What the older beaver eats, the younger one also eats. One can only envy the family idyll in water houses!
The main menu of these hard-working rodents is herbaceous plants. What a beaver eats is often shown in cartoons. In most cases, we see on screens how these animals eat fish. This is not true - aquatic animals do not eat such food. They spend a lot of energy felling trees; they need to be replenished somehow in order to withstand such a load. And it’s definitely not fish that helps them with this!
What do beavers eat in the wild, and what are their favorite dishes? It is clearer than clear that this is a tree. Favorite delicacies are twigs of alder, aspen, and willow. A beaver eats up to 1 kg of wood per day. Bark, the woody pulp under the bark, is the best food for critters. They chew small twigs whole, like candy.
Such hard foods are difficult to chew and even more difficult to digest. The beaver's food system is quite ready for this work.
In winter time
How do water workers behave in the cold season, because water bodies freeze and everything around is covered in snow? It’s hard for them, but if you prepare well for the winter, then the frosts won’t be scary. The beaver sleeps most of the time in winter. But in order to sleep peacefully and on a full stomach, one family needs to prepare more than a ton of branches for the winter.
It is very cozy in a beaver hut, insulated for the winter. It’s only when the food runs out that the head of the family has to go fishing.
The body of beavers is adapted for swimming, and not for plowing snow, so they have a very difficult time in the cold and in snowdrifts. Therefore, they are making every effort to ensure that the reserves last until the weather warms up.
Curious facts
The life of beavers is very interesting; there are many interesting things in their way of life:
- Furry swimmers cover a distance of 700 meters underwater in 10-15 minutes.
- In just one night, a beaver can fell and clear a tree with a diameter of 30-40 cm.
- Territory of 3 square meters. km can be inhabited by just one family of beavers.
- The largest beaver dam built is 700 m long, which is a world record. Although in the state of New Hampshire there is a larger dam - 1.2 km.
- In the city of Bobruisk there are two monuments to beavers, which is not surprising if you pay attention to the name of the city.
Beavers are one of the most interesting animals on our planet. Self-sharpening incisor teeth help beavers not only cut down trees, but also build homes for themselves and even build dams.
Among the representatives of the rodent order, the beaver ranks second (after the copybara) in body weight, which reaches 32 kg. (sometimes 50 kg) with a body length of up to 80-100 cm and a tail length of 25-50 cm. In prehistoric times (during the Pleistocene era), beavers were much larger, their height reached 2.75 m, and their weight was 350 kg.
Modern beavers are divided into two species: the common beaver, common in Eurasia, and the Canadian beaver, whose natural habitat is North America. Due to the great similarity in appearance and habits between the two beaver populations, until recently the Canadian beaver was considered a subspecies of the common beaver, until it became clear that there is still a genetic difference between these species, since the common beaver has 48 chromosomes, while the Canadian one is only 40. In addition, beavers of two species cannot interbreed.
The beaver has a squat body, five-fingered limbs with strong claws and a wide paddle-shaped tail. Contrary to popular belief, the tail of beavers is not at all a tool for building their homes; it serves as a rudder when swimming. The beaver is a semi-aquatic animal, therefore, much in the appearance of this mammal shows its adaptability to being in water: between the toes there are swimming membranes, especially strongly developed on the front legs, in the eyes of the beaver there are nictitating membranes that allow you to see under water, the ear openings and nostrils close under water, large lungs and liver provide such reserves of air and arterial blood that beavers can stay under water for 10-15 minutes, swimming up to 750 m during this time. A thick layer of subcutaneous fat protects against the cold.
Beavers are exclusively herbivorous; they feed on the bark and shoots of trees, preferring aspen, willow, poplar and birch, as well as various herbaceous plants (water lily, egg capsule, iris, cattail, reed). In order to obtain bark and shoots, as well as for construction needs, beavers cut down trees, gnawing them at the base. An aspen with a diameter of 5-7 cm is felled by a beaver in 5 minutes, a tree with a diameter of 40 cm is felled and cut up overnight. A beaver gnaws, rising on its hind legs and leaning on its tail. Its jaws act like a saw: to fell a tree, the 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 the front side is covered with enamel, the back side consists of less hard dentin. When a beaver chews on something, the dentin wears down faster than the enamel, so the leading edge of the tooth remains sharp all the time.
Trees chewed by beavers:
Video about the life of beavers, where you can see how beavers gnaw trees:
Beavers live along the banks of slow-flowing rivers, as well as ponds, lakes, and reservoirs. For housing, beavers can dig holes in steep banks with several entrances, each of which is located under water so that land predators cannot penetrate there. If digging a hole is impossible, beavers build a special dwelling - a hut - right in the water. A beaver lodge is a pile of brushwood held together by silt and clay. The height of the hut can reach up to 3 meters, and the diameter up to 12 meters. Like a hole, a hut is a reliable shelter from predators. Inside the hut there are manholes under the water and a platform rising above the water level. The bottom of the hut is lined with bark and herbs. With the onset of the first frost, beavers additionally insulate the hut with new layers of clay. Air penetrates through the ceiling. In cold weather, clouds of steam can be seen above the beaver lodges. In the coldest weather, the temperature in the hut remains above zero, and even if the reservoir is covered with ice, the ice hole under the hut does not freeze, which is very important for beavers, because beavers store food reserves for the winter, prepared in winter, under the overhanging banks directly into the water, from where they then take them when the cold comes.
beaver hut
Beavers live alone or in families. A complete family consists of 5-8 individuals. The mating season for beavers is in winter. Cubs are born in April-May and can swim within one or two days. At the age of 3-4 weeks, beaver cubs switch to feeding on leaves and soft stems of grass, but the mother continues to feed them with milk for up to 3 months. Grown-up young animals usually do not leave their parents for another 2-3 years. In captivity, beavers live up to 35 years, in the wild 10-19 years.
The head of the beaver family marks the boundaries of his territory with the so-called “beaver stream” - special secretions that were previously actively used in medicine, and are now used in the creation of expensive perfumes.
In case of danger, beavers give an alarm signal to their relatives by striking the water with their tail.
To prevent water from flooding the hut during a flood or, conversely, the reservoir suddenly becoming shallow, beavers often build dams. Construction begins with beavers sticking branches and trunks into the bottom, strengthening the gaps with branches and reeds, filling the voids with silt, moss, clay and stones. They often use a tree that has fallen into the river as a supporting frame, gradually covering it on all sides with building material. The longest dam built by beavers was 850 meters long. If a dam somewhere begins to let in more water than necessary, the beavers immediately seal up this place. Thanks to their excellent hearing, beavers accurately determine the place where the water began to flow faster. One day, scientists conducted an experiment: on the shore of a reservoir, a tape recorder was turned on with the recorded sound of flowing water. Despite the fact that the tape recorder was standing on dry land and there was no sign of any flowing water, the beavers’ instinct worked and they immediately covered up the “leak” with mud.
Although beavers may seem like forest pests, beavers' activities actually have beneficial effects on the ecosystem. For example, the number of ducks in reservoirs improved by beavers is on average 75 times greater than in reservoirs without beavers. This is due to the fact that beaver dams and calm water attract shellfish and aquatic insects, which, in turn, attract waterfowl and muskrats. Birds bring fish eggs on their paws and there are more fish in beaver ponds. Trees felled by beavers serve as food for hares and many ungulates, which gnaw the bark from the trunks and branches. The sap that flows from undermined trees in the spring is loved by butterflies and ants, followed by birds. In addition, dams help purify water, reducing its turbidity, because silt lingers in them.
Beavers have long been hunted for their valuable fur and beaver stream. As a result, at the beginning of the 20th century, beavers were completely exterminated in many European countries, and the total number of beavers in Eurasia was only 1,200 individuals. In the 20th century, largely due to active efforts to restore the beaver population in the Soviet Union, the situation began to gradually improve. In 1922, beaver hunting was banned in the USSR, and in 1923 the Voronezh Beaver Reserve was founded, where ideal conditions were created for beaver breeding. Beavers from the Voronezh Nature Reserve were resettled throughout the USSR, as well as in Poland, China, the GDR and other countries. Currently, the number of beavers in Russia exceeds 340 thousand, almost half are of Voronezh origin. The reserve is still open today, and when you visit it, you can take home photos of beavers (about 300 of them live here) taken with your own hands. In addition to beavers, the reserve has 333 species of vertebrates.
In North America, beavers were also brought to the brink of extinction, but their protection in the USA and Canada began at the end of the 19th century, and now there are 10-15 million beavers on the American continent, which is many times higher than the number of beavers in Eurasia (where there are about 640 of them) thousand according to data for 2003), however, it is much inferior to the time when the fur trade in America was not yet in fashion (at that time there were 100-200 million beavers in America).
Canadian beavers now live far beyond their natural range. In 1946, the Argentine government imported 25 pairs of Canadian beavers to the Tierra del Fuego archipelago to begin the beaver fur trade in the region. However, beavers, having found themselves in an ecosystem where they had no natural enemies, multiplied so much that they threatened local forests. Currently, 200 thousand beavers live on the archipelago.
In addition to Argentina, Canadian beavers were brought to Sweden and Finland, from where the beavers moved to Northwestern Russia, where they began to compete for territory with Eurasian beavers. The number of Canadian beavers in North-West Russia can reach up to 20 thousand individuals.
In Russian there is a word "beaver", but it is not a synonym for the word "beaver". "Beaver" is an animal, and "beaver" is the fur of a beaver.
Domain: Eukaryotes
Kingdom: Animals
Type: Chordata
Class: Mammals
Squad: Rodents
Family: Beavers
Genus: Beavers
View: Common beaver
Spreading
Beavers inhabit the entire temperate zone of the Northern Hemisphere and are found in Europe, Asia and North America. In the north, the beaver's range borders on the forest-tundra, in the south – on the steppe zone. Beavers are aquatic animals, so they are found only on the banks of water bodies.
Most of all, these animals like small rivers with a quiet flow, streams, creeks, small lakes; beavers can also be found in wetlands of the forest. At the same time, these animals do not live in real (vast and treeless) swamps; you will not find a beaver on the banks of a mountain river, endless lake, sea or ocean.
The reason for this selectivity is that beavers feed on woody vegetation, so one way or another, the reservoirs they inhabit are located in the forest. And here again beavers show their selective taste; they will not live in every forest. The main condition for beavers is that trees should grow as close to the water's edge as possible, which is why small forest streams and lakes buried in thickets are favored by these animals. Beavers will not settle in a slender pine forest, in a forest growing on a rocky or wide sandy shore.
What do beavers look like?
Before I tell you what beavers look like, I would like to clarify a little. Very often when people use the words beaver and beaver, they mean the same thing - that is, the rodent itself. But these two words have different meanings. So, beaver is the name of the animal, and its fur is called beaver.
So what do beavers look like? The common beaver looks like a large rodent. The animal’s body length reaches 1 meter, height – up to 35 cm, with a body weight of 32 kg. The length of the beaver's tail is up to 30 cm, and the width is up to 13 cm. An amazing fact of these rodents is that the females are larger than the males.
The common beaver has short legs and a squat body. The hind legs of the river beaver are much stronger than the front ones. On its paws the rodent has swimming membranes and strong thickened claws. Beavers look quite unusual because of their amazing tail. The beaver's tail resembles an oar, it is flat, without hair and covered with horny scales.
The common beaver has a large head with a narrow muzzle, small eyes and prominent incisors at the front. A beaver's teeth are special; they are covered with durable enamel, grow throughout their lives and sharpen themselves. The common beaver has small and short ears that are barely visible in the thick fur. Despite this, the animal has excellent hearing.
Beavers look like real fur barons, because they have beautiful shiny fur. Beaver fur has two layers, which keeps this rodent warm and dry in cold winters. The first layer of beaver fur consists of coarse long hairs, and the second is a very thick, silky undercoat. The river beaver is also protected from the cold by the presence of a layer of fat under its skin.
Beavers look inconspicuous due to their coloring. The fur of the common beaver is light chestnut or dark brown, sometimes even black. The tail and limbs of the animal are black. The tail of the common beaver has wen and special glands.
The odorous substance produced by the tail glands of rodents is called beaver squirt. And the secret of the wen contains all the information about the owner, carries information about his age and gender. A guide to other beavers about the boundaries of the settlement territory is the smell of the beaver stream, which is unique for each individual. In the wild, the common beaver lives on average 15 years.
Varieties
The beaver family has only two species: the common beaver, or river beaver, and the Canadian beaver. Let's take a closer look at the types of beavers.
- River. This is a semi-aquatic animal, the largest rodent in size, inhabiting the Old World, the forest-steppe zone of Russia, Mongolia, and China. They settle along the banks of slow-flowing rivers, irrigation canals, lakes and other bodies of water, the banks of which are covered with trees and bushes.
- Canadian. In appearance it differs from the river beaver in having a less elongated body, a short head and larger ears. The color is blackish or reddish brown. It lives throughout almost the entire United States (except for Florida and most of Nevada and California), in Canada, except for the northern regions. It was brought to the Scandinavian countries, from where it independently penetrated into the Leningrad region and Karelia.
These two beaver species have different numbers of chromosomes and do not interbreed.
Lifestyle
Common beavers prefer riparian lines along slow-moving rivers and oxbow lakes, lakes and ponds, reservoirs, as well as quarries and irrigation canals. As a rule, mammals try to avoid wide and too fast river waters, as well as reservoirs that freeze to the very bottom in winter. For the beaver, it is very important to have tree and shrub vegetation on the shore, represented by soft deciduous trees, as well as a sufficient amount of herbs included in the diet.
Beavers swim well and dive well. Thanks to the large lungs and liver, large reserves of arterial blood and air are provided, which allows mammals to stay under water for a quarter of an hour. On land, the beaver becomes quite clumsy and vulnerable.
In case of danger, swimming beavers slap their tails quite loudly on the water surface and dive, which serves as a kind of alarm signal.
Common beavers live in families or alone. Complete families consist of five to eight individuals, represented by a married couple and young animals - offspring from the current and previous years. Settled family plots are sometimes occupied by the family for many years. Small bodies of water are inhabited by a full family or one single beaver, and on the largest ones - several families or many single beavers.
The beaver rarely moves more than 150-200 m away from the aquatic environment. The border of the territory is marked with a special secretion applied to the surface of mud mounds. Beavers are active only at night and at dusk. During the summer and autumn periods, an adult mammal leaves its home in the evening hours and works until the morning.
In winter, beavers do not hibernate, but they rarely come to the surface of the earth - only during thaws. All beaver activity in winter takes place in a hole or hut and under the ice of a reservoir. For the winter, beavers make large supplies of food for themselves from twigs and branches, which they store by strengthening them at the bottom of reservoirs near the entrance to their homes.
Housing
Beavers live in burrows or huts. The entrance to a beaver's home is always located under water for safety. Beavers dig burrows in steep and steep banks; they are a complex maze with 4–5 entrances. The walls and ceiling of the hole are carefully leveled and compacted. The living chamber inside the hole is located at a depth of no 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, the beaver raises the floor by scraping soil from the ceiling. To prevent the section of the river above the entrance to the hole from freezing in winter and trapping the animals in the hole, they cover this place with a special canopy. Sometimes the ceiling of the hole is destroyed and in its place a durable flooring of branches and brushwood is built, turning the hole into a transitional type of shelter - a semi-hut. In the spring, during high water, beavers build hammocks made of branches and twigs with a bedding of dry grass on the tops of bushes.
Huts are built in places where digging a hole is impossible - on flat and low swampy banks and in shallows. Beavers rarely begin building new housing before the end of August. The huts have the appearance of a cone-shaped pile of brushwood, held together by 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 to predators; air enters through a hole in the ceiling. Despite popular belief, beavers apply clay using their front paws, not their tail (the tail serves only as a rudder). Inside the hut there are manholes into the water and a platform rising above the water level. With the first frost, beavers additionally insulate their huts with a new layer of clay. In winter, the temperature in the huts remains above zero, the water in the holes does not freeze, and beavers have the opportunity to go out into the under-ice layer of the reservoir. In severe frosts, there is steam above the huts, which is a sign of habitation.
Dam construction
What else surprises and delights in the way of life of animals is how beavers build a dam. They are located downstream from their habitat.
Such structures prevent the river from shallowing and contribute to its flooding. This means they contribute to the settlement of animals in flooded areas and increase the ability to find food. This is why beavers build dams.
The width and depth of the river, the speed of the flow determine what the beaver dam will be like. It must block the river from one bank to the other and be strong enough so that it does not get carried away by the current. Animals choose where there is a convenient place to start construction - a fallen tree, a narrowing riverbed.
Hardworking beavers build a dam by sticking twigs and stakes into the bottom and filling the gaps between them with cobblestones, silt, and clay. Beaver dams must be strengthened constantly, month after month, year after year, to prevent them from being washed away. But that doesn't stop the beavers! As a result, the dam becomes stronger and bushes and trees grow on it. You can even cross it from one bank to the other.
To build and prepare food, beavers cut down trees, gnawing them at the base, gnawing off branches, then dividing the trunk into parts. A beaver fells an aspen with a diameter of 5–7 cm in 5 minutes; a tree with a diameter of 40 cm is felled and cut up overnight, so that by morning only a sanded stump and a pile of shavings remains at the place where the animal works. The trunk of a tree gnawed by a beaver takes on a characteristic “hourglass” shape.
Beavers eat some of the branches of a fallen tree on the spot, while others are demolished and towed or floated across the water to their home or to the site of dam construction. Every year, walking the same routes for food and building materials, they trample paths on the shore that are gradually filled with water - beaver channels. They float wood food along them. The canal length reaches hundreds of meters with a width of 40–50 cm and a depth of up to 1 m. Beavers always keep the canals clean.
The area transformed as a result of the activity of beavers that settled on it is called a beaver landscape.
Nutrition
Beavers are exclusively herbivorous; they feed on the bark and shoots of trees, preferring aspen, willow, poplar and birch, as well as various herbaceous plants (water lily, egg capsule, iris, cattail, reed). In order to obtain bark and shoots, as well as for construction needs, beavers cut down trees, gnawing them at the base. An aspen with a diameter of 5–7 cm can be felled by a beaver in 5 minutes; a tree with a diameter of 40 cm can be felled and cut up overnight. A beaver gnaws, rising on its hind legs and leaning on its tail. Its jaws act like a saw: to fell a tree, the 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 the front side is covered with enamel, the back side consists of less hard dentin. When a beaver chews on something, the dentin wears down faster than the enamel, so the leading edge of the tooth remains sharp all the time.
Reproduction
The river beaver forms monogamous pairs, which eventually develop into small family groups. The right to reproduce in them, however, belongs only to the leading pair; the remaining individuals, after growing up, are forced to leave the group in order to organize their own colony.
The mating season for beavers occurs in January-February. Pregnancy lasts about 3 months, usually from 1 to 3 cubs are born. The female carefully takes care of the newborns, cleans and feeds them. At six weeks of age, beaver cubs are weaned and begin to eat solid food.
How long do beavers live?
The average lifespan of an ordinary beaver in natural conditions is approximately fifteen years, and when kept in captivity - a quarter of a century. Not only natural enemies, but also some diseases contribute to shortening life spans in nature. Despite the fact that common beavers have a fairly stable immunity to some of the most common infectious diseases, including tularemia, the death of mammalian rodents from pasteurellosis, paratyphoid fever, as well as hemorrhagic septicemia, coccidiosis and tuberculosis has been recorded.
Of the flukes, the common beaver contains the liver fluke, as well as Stichorchis and Travassius. It is the last two diseases that have a very negative impact on the growth of the number and overall beaver population.
Among other things, if the spring flood is too strong, young beavers die or all established families are completely broken up, and winter floods can lead to a reduction of the entire population by almost 50%.
Economic importance
Beavers have long been hunted for their beautiful, valuable fur. In addition, beaver stream is used, which is used in medicine and the perfume industry. Beaver meat is eaten. Interestingly, Catholics considered it a Lenten food. The scaly tail was misleading, because of which the rodent was considered a fish. Beaver poses a danger when eaten as a natural carrier of salmonellosis.
The influence of beavers on the ecological situation
The appearance of beavers in rivers and especially their construction of dams 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 their feet bring fish eggs. The fish, once in favorable conditions, begin to reproduce. Trees felled by beavers serve as food for hares and many ungulates, which gnaw the bark from the trunks and branches. The sap that flows from undermined trees in the spring is loved by butterflies and ants, followed by birds. Beavers are protected by muskrats; muskrats often live in their huts along with their owners. Dams help purify water, reducing its turbidity; silt lingers in them.
At the same time, beaver dams can cause damage to human buildings. There are known cases when spills caused by beavers flooded and washed away streets and railroad tracks and even caused crashes.
Video
Sources
- https://ru.wikipedia.org/wiki/Ordinary_beaver http://hunt-i-photo.ru/opredelitel-zverej/rechnoj-bobr http://udivitelno.com/animals/item/199-bobr
There are two types of beavers in nature: ordinary beaver and Canadian. The first species lives in Eurasia, the second in North America. These animals have close family ties with squirrels. Certain structural similarities between the lower jaw and the skull indicate commonality. At the same time, the behavior of these representatives of the rodent order varies significantly. The beaver lives only near water. She is his native element. It cannot exist in any other environment. This applies to both Canadian and Eurasian animals. Both species have certain differences, and it is not for nothing that they were separated into separate populations.
Differences between Canadian and common beavers
Externally, representatives of two different species are very similar to each other. But Eurasian beaver is larger. He has a larger and less rounded head. The muzzle is more graceful, so to speak, and shorter. The undercoat is shorter and the tail is narrower than that of the Canadian. The limbs are shorter, so the Eurasian is less adapted to walking on its hind legs. Common beavers have longer nasal bones. The nasal openings are triangular in shape. For Canadians it is oval. The anal glands of the Eurasian are larger. The color of the fur also varies.
Almost 70% of common beavers have brown or light brown fur. Chestnut shade is present in 20% of Eurasians. Dark brown has 8%, and pure black only 4%. Among Canadians, half of all beavers sport light brown skins. 25% boasts a reddish-brown tint. Brown skins are worn by 20%, and black by the remaining 5%.
The two species differ in the number of chromosomes. Canadians have 40, and Eurasians have 48. Despite this, people have made many attempts to crossbreed representatives of different continents. Moreover, the females were from Europe, and the males were from America. As a result, females either did not give birth at all or gave birth to dead cubs. From this we can conclude that interspecific reproduction is impossible. These populations are separated from each other not only by thousands of kilometers of ocean surface, but also by DNA features.
Beaver sizes and appearance
In beavers, females are larger than males. They dominate over males. The Canadian beaver weighs from 15 to 35 kg. The usual weight is 20 kg with a body length of about 1 meter. These animals grow throughout their lives, so old beavers can reach a weight of 45 kg. The common or Eurasian beaver has a body weight of 30-32 kg with a body length of 1-1.3 meters. The usual body height is 35 cm.
The animals' bodies are squat. There are 5 fingers on the limbs. There are membranes between them. The claws are flat. The tail is shaped like an oar. Its length does not exceed 30 cm. It is usually 10-12 cm wide. There is no hair on the tail. It is covered with horny plates, between which sparse hairs emerge. In the middle of the tail, a horny protrusion stretches along its entire length, reminiscent of a ship's keel. The ears are short, the eyes are small. The undercoat is dense, the guard hairs are coarse. The fur is beautiful, practical and in commercial demand.
Reproduction and lifespan
Beavers mate for life. Only death can separate the betrothed. The mating season occurs in winter. Mating occurs in water. The gestation period for the common beaver is 107 days, for the Canadian beaver it is 128 days. There are from 2 to 6 cubs in a litter. Their usual weight reaches 400 grams. Milk feeding lasts 3 months. Babies begin to swim a week after birth. In males, puberty occurs at 3 years. Most females also at 3 years old. Every fifth female is capable of reproducing offspring at 2 years. The lifespan of beavers in nature is 20-25 years. In favorable conditions, the animal lives up to 35 years.
Behavior and nutrition
The beaver is a herbivore. He eats sedge and water lilies with pleasure. It gnaws the bark of aspen, poplar, willow, alder, birch, and maple. But, in any case, young shoots tempt him more. At first glance, it may seem that these rodents cause irreparable harm to the environment. But this is a mistaken opinion. Animals bring undoubted benefits to the ecosystem by creating wetlands. They are simply necessary for many other species of animals.
Beavers cut down trees, but not just anywhere, but in certain places, from which it is very convenient to drag heavy trunks to the river. The animals gnaw the bark, branches, and leaves, and the trunks are used to build a dam. It is thanks to this that dams are created. Various insects settle in them, thereby attracting numerous species of birds. Birds bring fish eggs on their feathers and legs. Thus, fish appear in the dams.
Water, in turn, seeping through such structures is cleared of heavy suspended matter and silt. Many plants die in dams. That is, a large amount of dead wood appears. It is necessary for certain types of animals and plants. Trees damaged by beavers also serve as food for ungulates. That is, nature only benefits from the activity of rodents, but humans lose. The created dams can overflow and destroy crops, as well as erode highways and railway embankments.
The construction of dams by beavers is a different matter. These amazing rodents live in burrows or special “houses” that they make themselves. Burrows are dug in steep banks. They are long and represent a whole labyrinth with several entrances. The floor in such burrows is slightly above the water level. If the river floods, the animals scrape the earth from the ceiling and thus “raise” the floor.
In addition to burrows, beavers build “houses.” In the shallows, they collect dry tree branches in a heap and cover them with clay, earth and silt. A free space is created inside the heap, rising above the water. It is entered from under the water. The height of such a structure reaches 3 meters and the diameter is 10 meters. The walls of the “house” are very strong. They serve as excellent protection against predatory animals. When constructing their homes, animals work with their front paws. In preparation for cold weather, an additional layer of clay and earth is applied to the walls. Therefore, during the winter months, such structures always maintain above-zero temperatures, and the water in the manholes does not freeze. Beavers maintain perfect order in their homes. There is never any food waste or excrement in them.
The beaver is a social animal, so all rodents form families. Usually there are up to 10 individuals in one family. These are married couples and young animals that have not yet reached puberty. One family can live on the same plot for a whole century. The length of such a plot of land along the coast reaches 3-4 km. Rodents rarely move more than 200-300 meters from the shore. Their whole life is connected with the river. There are also solitary beavers - these are young, sexually mature bachelors who have just left their family. They live in burrows and eventually start a family.
Dam construction
Why do beavers build dams?? So that they have more water. Very often, a family of beavers takes a liking to a small stream or small river. To raise the water level, rodents build dams. As a result, the river turns into a small lake, and for animals this is a real haven. In the water they mate, enter their homes and, naturally, protect their lives from predatory animals. A beaver can stay under water for a maximum of 15 minutes. In case of obvious danger, such results of scuba diving are very helpful for rodents.
First, the beavers decide on the construction site. Preference is given to those places where the opposite banks are separated from each other at the shortest distance. The presence of trees near the shore also plays an important role. This is the main building material. The animals stick the gnawed trunks vertically into the river bottom. Large stones are placed between them and covered with silt. Branches are piled on the above-water part. They are held together with clay. It turns out to be a very strong structure.
The length of the dam can reach up to 30 meters. At the base it is wider, about 5-6 meters. It narrows with height. At the very top the dam reaches a width of 2 meters. The height can be 3, 4, or 5 meters. History knows of cases where beavers built dams 500 and even 850 meters long. In case of strong currents, additional dams are built and special drains are made so that the structure does not collapse when the river floods. Rodents constantly monitor the condition of the dam. Minor leaks and damage are immediately repaired.
Beaver population
As for the number of Canadian beavers, there were once about 100 million of them in North America. By the end of the 19th century, rodents were almost completely exterminated. From a huge population, only pitiful crumbs remained. By the beginning of the 20th century, bans on catching these animals were introduced. Today there are more than 10 million rodents in America. In Eurasia the situation was even worse. At the beginning of the 20th century, approximately 1,200 poor animals lived in vast territories. After 100 years, thanks to the bans, their number increased to 700 thousand. In most European countries, the common beaver has received a rebirth, since in these regions it was exterminated back in the 17th-19th centuries.