Beavers are extremely useful animals that can easily be called the best natural engineers. Although they are increasingly called "pests", they are our best allies in the fight against drought. Every year they carry out holding work, the cost of which is enormous. Beavers build dams, which are a natural way of collecting water, shallowing flood waves, stabilizing groundwater levels, and purifying water.
1
Beavers are a genus of mammals (Castor) from the beaver family (Castroidae).
This genus includes species found in Eurasia and North America.
2
The genus Castor (beaver) includes two living species: Castor fibre, the European beaver, and Castor canadensis, the Canadian beaver.
There are also two extinct species: Castor Californicus and Castor veterior.
3
The European beaver and Canadian beaver are closely related and were considered a single species in the past.
They look very similar, but differ in genetics, namely the number of chromosomes. The Canadian beaver has 40, and the European beaver has 48, which means that both species cannot interbreed.
4
The European beaver is also called the common, river or eastern beaver.
It is considered the largest rodent in Eurasia, since its body weight is about 29 kg and its length is up to 110 cm.
5
The body structure of beavers makes it easier for them to swim and dive.
They have a massive, streamlined body connected to the head, with almost no pronounced neck. The body of European beavers is somewhat slimmer than that of Canadian beavers, which also have a wider chest. Beavers' front feet are prehensile, and their massive, strong hind feet end in toes connected by a webbed membrane.
6
Beavers have a short head, with dark, small ears and small, protruding eyes located close together.
Beavers' eyes are equipped with a third transparent eyelid that protects the eye while diving. During diving, the ear and nasal passages are closed by folds of skin, and the mouth is tightly closed thanks to the bifurcated upper lip and wide diastema. When swimming, the nose, eyes and ears of beavers are in the same plane and are held above the surface of the water.
7
Beaver tails are large, oval, flattened, with a slightly pointed end, covered with black horny scales, from which thin hairs grow.
European beavers have a slightly narrower tail. The tail serves as a rudder when swimming and is the beaver's natural support on land. It is also the body's natural fat reserve and thermoregulatory organ.
8
Beavers of both sexes have two cavities under the skin, between the pelvis and the base of the tail, two anal glands and two sacs (preputial glands).
The yellowish secretion from the sacs (castoreum) is used by animals to lubricate their fur and, in combination with urine, to mark their territory. The aromatic component of this secretion is primarily castoramine. Castoreum solutions (such as ambergris) are aroma fixatives in perfumery and a fragrance additive in soaps and powders. The secretion of the anal glands helps individuals recognize each other.
9
Beavers' skin is covered with thick, soft and shiny fur.
The fur is so thick that 12-23 thousand furs grow on one square centimeter of skin. hair. It consists of down and guard hair, which are designed in such a way that when diving, air is retained in the fur, due to which beavers receive an additional insulating layer and greater buoyancy.
10
The color of beavers depends on the habitat of the animals.
It can be black, shades of brown or light. Darker coloring is characteristic of beavers from Scandinavia or Siberia, and lighter coloring is characteristic of those living in southern regions, such as Mongolia. Black color is a recessive trait. In Poland, black and brown individuals are found simultaneously. Canadian beavers are red or black-brown in color.
11
Beavers do not have sexual dimorphism.
The external genitalia are located in the pseudocloaca.
12
Beavers are family animals and are essentially monogamous. Only after the death of a partner do they look for a new one.
Females and males reach full maturity at the age of 3 years. They breed once a year, pregnancy lasts 105-107 days, chicks are born between April and June. From 2 to 6 cubs are born in a litter (the Canadian beaver has 1-4), which are completely independent, see immediately after birth and can swim 24 hours after birth. Their mother feeds them milk for 90 days, although they begin to eat plant foods already in the second week of life. The young remain with their parents until they are 2 years old, after which they search for their own territory.
13
The European beaver lives about 30 years, the Canadian one - from 10 to 19 years.
Beavers living in zoos can reach an age of 35 to 50 years.
14
Beavers are active at night, with their peak activity occurring between 22:23 p.m. and XNUMX:XNUMX p.m.
During the day they spend time in burrows, where they sleep and rest.
15
Beavers overwinter in a common burrow chamber or hut—a protective and breeding structure for beavers built in a burrow carved into a steep bank or on a raised platform in a wetland.
The houses are built from tree branches, soft vegetation and mud. Beavers enter them through an underwater entrance or through several entrances. The roofs of the houses protrude above the water level. The huts have a height of 1 to 3 m and a diameter of up to 12 m. To better cover the entrances to the huts, beavers build dams to raise the water level. The greater depth makes it easier to swim, dive and carry materials freely. The largest dam in the world built by beavers, 850 m long, is located in Canada at the southern tip of Buffalo National Park. The second, 652 m long, is located in the US state of Montana.
16
Their teeth play an important role in the life of beavers.
Thanks to their long and strong incisors, beavers can perform most of their life activities, such as cutting down trees and building dams and houses. The pressure force of the incisors corresponds to a weight of several tons per cm2, thanks to which they can cut hard beech or hornbeam wood, as well as trees with a diameter of up to 1 m. Only the lower incisors, which are about 15 cm long, play an important role in the bite, the upper incisors serve as a point support. The front surface of the incisors is brown-red or orange. Beavers have a characteristic diastema, reaching approximately 70% of the total jaw width. Beavers' teeth grow continuously throughout their lives and require constant grinding.
17
Beavers are herbivores, feeding on almost all available parts of coastal and aquatic plants.
The beaver's body is not able to digest and use all the food at once, since the main part of it is cellulose. This is why beavers use caecotrophy (a two-step digestion method). They produce two types of feces and eat one of them containing ingredients that have been pre-processed by bacteria.
18
Beavers usually feed within 20 m from the shore of a reservoir, but can also go to further territories.
During the night they can swim up to 20 km. Young beavers can travel several hundred kilometers in search of a partner or a new place.
19
Beavers make various sounds, but hearing them is relatively rare.
These voices are similar to the sounds of whistles, grunts, sighs, whimpers, owls or pigs. Individual sounds are thought to be associated with specific social behaviors. Beavers, for example, emit a characteristic greeting call when meeting after a long break. A characteristic behavior of beavers is also the loud slapping of their tail on the surface of the water, warning other individuals of approaching danger and informing an intruder that they have been spotted. When meeting a person, a beaver turns to face him, sticks slightly to the ground and hits the ground with its tail.
20
Beavers carefully monitor the hygiene of their fur.
Coming out of the water, they shake off the remaining water from their fur, then squat down and rub their belly with slow movements of both paws. It is also used to clean the forearms, thighs and tail. They use the claws of their index finger to clean the skin around the eyes and the corners of the lips. The forked claw of the second toe of the hind limb is used to clean other parts of the body, after which the fur is lubricated with the secretion of the anal glands.
21
Beavers are semi-aquatic animals, very territorial and active at night.
They live in a family group, including parents and up to two generations of offspring. The territory of one family occupies an area of 1-4 km along the length of the watercourse.
22
Beavers can remain underwater continuously for up to 15 minutes.
While diving, their heart rate decreases.
23
Beavers have the highest brain-to-body mass ratio of any rodent.
This can be seen not only in the behavior of beavers, but also in their ability to act instinctively and logically (they can build steps to climb higher). They can adapt the environment to their needs. The intelligence of beavers is compared to the intelligence level of rats.
24
In Poland, beavers are partially protected.
Beavers were the object of special care of Polish kings and princes. At the beginning of the XNUMXth century, Boleslav the Brave banned beaver hunting in the territories under his control and established the position of beaver, who took care of the beavers living in this territory. There was also a beaver guard, because beavers were royal property. In most European countries, castor fiber is protected.
25
In the past, beavers were hunted primarily for their pelts and meat, as well as their beaver costumes.
The beaver costume was considered a miracle cure. Our ancestors loved to wear beaver fur, from which they sewed collars and caps.
26
Beavers are very useful animals, which significantly outweighs the negative consequences of their activities (flooding of agricultural and forest areas).
Their activities restore a favorable water regime, preserve and increase the biodiversity of the environment, reduce erosion, and increase the rate of self-purification of water. During periods of high water, beavers deliberately open the dams they have built to drain excess water. Hydraulic structures built by beavers change the nature of the watercourse. New habitats are created, retention increases, and even the physical and chemical parameters of water change. Thanks to them, new environments are created that are favorable for populations of invertebrates, fish, amphibians and flora.
27
Beavers have natural enemies: wolves, lynxes, bears, wolverines, foxes, and stray dogs.
However, the most serious enemy of these animals is man.
28
International Beaver Day is April 7th.
Today is the birthday of Dorothy Richards, an American researcher of these animals. It was first celebrated in 2009 at the initiative of the American organization Beavers: Wetlands & Wildlife (BWW). The purpose of the holiday is to draw attention to the role in nature and protection of these large rodents, both the European and Canadian beaver.
29
The Canadian beaver is considered one of the symbols of Canada. It is also considered the symbol of the states of Oregon and New York.
His image appears on the Canadian five-cent coin.
30
Finno-Ugric peoples living in Western Siberia (Khanty and Mansi) consider beavers to be animals with a soul.
Among the ancient Germans, Finns and Norwegians, beavers were sacrificial animals.
31
In the 16th century, the Catholic Church allowed the consumption of beaver meat during Lent.
As an aquatic animal, it was considered fish-like. Beaver tail (the name given to the splashtail, which is naturally covered with scales) was served as a Christmas Eve dish.
