Presentation on the topic "river beaver"
“Once upon a time there lived a beaver!”
- Prepared by:
- Krechetova Yulia Stanislavovna,
- primary school teacher
- MBOU "School No. 38"
- (branch)
- Ryazan
BEAVER
A wonderful worker, I am a carpenter, I am a carpenter. My teeth are sharp, They helped build the house. The fur coat is so warm, It helps not to get wet, I’m building a dam in the river, Clay, branches, wood. Even though the home is not a tent, one lives well...
The first miracle is beaver teeth.
The tool of labor of the beast - the lumberjack -
unusually powerful incisors,
of which there are a pair on each jaw.
The beaver rests with its upper incisors
into the trunk, cutting off the shavings with the lower ones.
The second miracle is a beaver fur coat.
The beaver has unusually thick fur.
In winter the fur is even thicker. This is possible due to unusual shape hairs During bathing, the beaver's skin does not get wet. To prevent the fur from getting wet, the beaver lubricates it with an oily secretion (grease), which is secreted from special glands.
The third miracle is the beaver tail.
The beaver's tail is bare and covered with horny scales. But these are not the same scales that cover the body of the fish, but special thickenings of the skin.
- Without a tail, the animal would not be able to gnaw
trees, because the tail is its main support
at work.
- A beaver couldn't do it so well
swim because the tail serves
he has both the oar and the rudder.
- The tail protects the animal from overheating. The whole body is dressed in a warm fur coat, and only thanks to the bare tail, excess heat is transferred to the environment.
The fourth and fifth miracles are beaver lodges and dams.
Beavers are hard workers. Their favorite activity is construction. As soon as they like the area somewhere, they immediately begin to build. And definitely near water. The fact is that animals feel calm and safer in water than on land.
Why do beavers build dams?
When the dam is built, the water level in this place begins to rise, thereby flooding the beavers' home. And to ensure their safety, they absolutely need this. After all, a predator, hunting for its prey, will not go into the water. And the deeper underwater the beaver’s house is, the safer it is.
How do beavers build dams?
First, beavers choose a place on the river that they like, most often it is shallow water. Then, very painstakingly, day after day, they drag out all kinds of twigs and sticks and build a kind of partition from them. This entire structure can be supported by silt and stones.
Schematic representation of a beaver dam and house.
As you can see, the house is a separate building.
Beaver nutrition.
For beavers, it is important to have soft trees and shrubs along the banks of the reservoir. hardwood, as well as the abundance of aquatic and coastal herbaceous vegetation that makes up their diet.
The sixth miracle is beavers.
Beavers live alone or in families. A complete family consists of 5-8 individuals: married couple and young beavers - the offspring of last and current years. A family plot is sometimes occupied by the family for many generations. A small pond is occupied by one family or single beaver.
The seventh miracle - the beavers are returning!
Beavers have long been hunted for their beautiful and durable fur.
In addition to valuable fur, they produce beaver stream, used in perfumery and medicine. Beaver meat is edible; Meanwhile, it is rarely eaten.
In the 20s of the 20th century, only a few hundred of these animals survived on the territory of our country. The state took beavers under its protection.
As a result of a complete ban on hunting and the creation of 2 reserves - in the Voronezh region and Western Siberia The beavers have multiplied again.
INTERESTING FACTS
Beaver dams are the only structures built by animals that can be seen from space.
Beavers are excellent swimmers. The toes of their strong hind legs are connected by swimming membranes. Pushing off the water with powerful movements, they can reach speeds of up to 10 km/h.
By closing the ear and nostril valves, as well as the mouth, the beaver can remain underwater for 10 to 15 minutes, while covering a distance of up to 700 meters.
Beavers have transparent eyelids
which allows them to
see underwater
and protect your eyes.
The beaver is on the coat of arms of Irkutsk. More precisely, the babr (Ussuri tiger), which is a mythical mixture of a beaver and a tiger.
The beaver has been featured on Canadian nickels since 1937.
Slide 1
Slide 2
The beaver is a large rodent adapted to a semi-aquatic lifestyle. The length of its body reaches 1-1.3 m, the height at the shoulder is up to 35.5 cm, and the weight is up to 30-32 kg. Moreover, females are larger than males. The beaver's body is squat, with shortened 5-fingered limbs; the rear ones are much stronger than the front ones. Between the toes there are swimming membranes, strongly developed on the hind limbs and weakly developed on the forelimbs. The claws on the paws are strong and flattened. The claw of the second toe of the hind limbs is forked - the beaver combs its fur with it. The tail is oar-shaped, strongly flattened from top to bottom; its length is up to 30 cm, width - 10-13 cm.
Slide 3
Hair is only present at the base of the tail. Most of it is covered with large horny scutes, between which sparse, short and stiff hairs grow. Up by midline the tail has a horny keel. The beaver's eyes are small; The ears are wide and short, barely protruding above the level of the fur.
Slide 4
The ear openings and nostrils close under water, the eyes are closed by nictitating membranes. Large lungs and liver provide them with 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. On land, beavers are quite clumsy.
Slide 5
The beaver has beautiful fur, which consists of coarse guard hairs and very thick silky underfur. The fur color ranges from light chestnut to dark brown, sometimes black. The tail and limbs are black. Shedding occurs once a year, at the end of spring, but continues almost until winter. In the anal area there are paired glands that secrete a strong-smelling secretion - beaver stream. The beaver uses this secretion to mark its territory and lubricate its fur, protecting it from getting wet.
Slide 6
* Beavers live alone or in families. A complete family consists of 5-8 individuals: a married couple and young beavers - the offspring of the past and current years. A family plot is sometimes occupied by the family for many generations. A small pond is occupied by one family or single beaver. On larger bodies of water, the length of the family plot along the shore ranges from 0.3 to 2.9 km. Beavers rarely move more than 200 m from water.
Slide 7
Beavers mark the boundaries of their territory with the secretion of their musk glands - a 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 strikes on the water and whistle-like calls. When in danger, a swimming beaver slaps its tail loudly on the water and dives. The clap serves as an alarm signal to all beavers within earshot.
Slide 8
Beavers are active at night and at dusk. In summer, they leave their homes at dusk and work until 4-6 am. In the fall, when the preparation of feed for the winter begins, the working day lengthens to 10-12 hours. In winter, activity decreases and shifts to daylight hours; At this time of year, beavers almost never appear on the surface. At temperatures below −20 °C, animals remain in their homes.
Slide 9
Beavers live in burrows or huts. The entrance to a beaver's home is always located under water. Beavers dig burrows in steep banks; they are a complex labyrinth 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 also raises the floor, scraping soil from the ceiling.
Slide 10
In the spring, during high water, beavers build nests on the tops of bushes from branches and twigs with a bedding of dry grass.
Slide 11
In reservoirs with changing water levels, as well as on small streams and rivers, beaver families build their famous dams (dams). This allows them to raise, maintain and regulate the water level in a reservoir.
Slide 12
Dams are built below the beaver town from tree trunks, branches and brushwood, held together by clay, silt, pieces of driftwood and other materials that beavers bring in their teeth or front paws. If the reservoir has a fast current and there are stones at the bottom, they are also used as building material. The weight of stones can reach 15-18 kg.
Slide 13
For the construction of the dam, places where trees grow closer to the edge of the shore are selected. Construction begins with beavers vertically sticking branches and trunks into the bottom, strengthening the gaps with branches and reeds, filling the voids with silt, clay and stones. They often use a tree that has fallen into the river as a supporting frame, gradually covering it on all sides. building material. Sometimes branches in beaver dams take root, giving them additional strength.
Slide 14
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 towards the flow. If the current is very strong, beavers build small additional dams further up the river. The dam is often provided with a drain to prevent it from being breached by floods. On average, it takes a beaver family about a week to build a 10 m dam. Beavers carefully monitor the safety of the dam and patch it if it leaks. Sometimes several families working in shifts are involved in the construction.
Slide 15
The usual length of the dam is 20-30 m, 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 can easily support the weight of a person.
Slide 16
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.
Slide 17
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 on its bark and begins to quickly drive 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. 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.
Slide 18
Beavers are monogamous and the female is dominant. Offspring are born once a year. The mating season lasts from mid-January to the end of February. Pregnancy lasts 105-107 days.
Presentation "Beavers"
Target. Forming interest in the Voronezh State Natural Biosphere Reserve among older preschoolers.
Tasks:
- Introduce children to the history of river beaver conservation in the Voronezh Nature Reserve
- Introduce preschoolers to interesting facts from the life of these animals
- Develop an interest in animals "like our little brothers" .
Slide 3 Many years ago, on the forest river Usmanka, not far from Voronezh, biologists found several families of beavers.
4 slide. By that time there were very few of these animals left. They were killed to get beautiful and warm fur. The beavers that were found had to be saved somehow.
5 slide. So scientists proposed creating a beaver reserve in this place. That's what they called him back then - "beaver" reserve.
6 slide. The emblem of the reserve features figures of a beaver and a deer framed by branches. The image of a roaring deer looks more impressive, but the reserve owes its creation and existence primarily to the beaver.
Slide 7 Beaver – "The main thing" animal of the Voronezh Nature Reserve. The beaver spends a lot of time in the water (rivers and lakes). The luxurious beaver fur is warm and so thick that not a single drop of water can penetrate between the fibers. Yes, and greased. Beavers carefully comb their fur with their teeth, front paws, and special scratching claws on their hind paws.
8 slide. The beaver has a strong tail covered with dense scales. The beaver's tail is both a rudder and an oar at the same time. With such a tail it is convenient for the beaver to swim and dive. Hitting the water with his tail, (9 slide) a beaver can warn the rest of its family of danger. The noise created by this can be compared to a gun shot - it will not go unnoticed!
10 slide. The beaver's hind legs are much larger than its front legs. Unlike the front paws, they are equipped with membranes and serve mainly for swimming.
11 slide. The beaver is an excellent swimmer and diver. It can remain underwater for up to 15 minutes without rising to the surface for air. A split second before diving, the beaver closes all openings: the nostrils and ears - with the help of muscles specially provided for this, the eyes - with a transparent nictitating membrane. He is also able to close his lips behind his incisors, allowing him to use his teeth underwater without the risk of choking.
Slide 12 and slide 13. The beaver never breaks vegetarian diet, using exclusively plant foods: leaves, branches, plants, tree bark, etc. His favorite trees are willow, poplar, birch and alder.
Slide 14 The beaver has powerful teeth, with which it knocks down trees and strips the bark from them. A beaver's teeth grow throughout its life. They are covered with orange enamel, which protects them from being worn down too quickly. If a beaver's teeth are light, this indicates that the beaver is not feeling well or is already old.
Slide 15 At the end of summer, beavers actively cut down trees. Thanks to its strong incisors, this rodent easily performs the work of a woodcutter. In half an hour, he can fell a tree whose trunk is 12 cm in diameter. Beavers gnaw off the branches and transport them across the water to the hut. The branches are placed in water and pressed down with stones. In winter, beavers will have a substantial supply of food.
16 slide. The beaver is a tireless builder. He never stops arranging his family's habitat. It all starts with the construction of a dam, which allows you to create a reservoir of ideal depth. Then, depending on the characteristics of the area, he builds a hole or hut.
Slides 17 and 18. Where the banks are steep, the animals dig holes. It's clean, dry, comfortable here. The entrance is hidden under water.
Slide 19 He is building a hut among a dam. He lays large branches on the shallows, fastens the branches with silt (20 slide). He then proceeds to pile up the branches and then plug the cracks. Finally, the beaver can only dig a living chamber in this tightly packed pile.
21 slides. The entrance to the hut is always under water - so a predator who wants to look inside will have to be an excellent swimmer and diver.
A feature of all types of beaver dwellings is the presence of two levels. On the first "floor" , located just above the water level, the beaver dries out. On the second "floor" family relaxing and having lunch. From their bed, beavers carefully monitor changes in the water level: if the water drops, it means that a gap has appeared in the dam, and the beaver is in a hurry to seal it; if it rises, it’s time to open the dam slightly and release the excess water.
22 slide. No hibernation! The beaver never hibernates in winter. But in winter, during extreme cold, its activity noticeably decreases. Sometimes he doesn’t show his face outside for weeks, or at least he doesn’t get out onto land. However, the beaver has to quite regularly dive under the ice for provisions that are stored at the bottom of the reservoir, and at the same time stretch its paws. It is inconvenient and unsafe for beavers to move through the snow, because... Their paws are short, their tail drags in the snow, and can freeze in the cold.
Slide 23 Beware, predators! There are plenty of predators in nature ready to feast on beavers. Among the most formidable enemies are the wolf, bears, wolverine, lynx, and otter. The latter, being an excellent swimmer, from time to time tries to climb into a beaver hole or hut and dine on newborn beaver cubs. Fleeing from predators, the beaver dives deep into the water, faking its death and thus deceiving them. Hoodie crow, pike, and wolf are dangerous for small beavers.
24 slide. Exemplary family. The family consists of a father, mother and cubs born in the current and last year. Beaver is a wonderful mother: she is very attentive, constantly making sure that the kids are comfortable.
25 slide. Beaver babies are born in the spring. Their eyes are open, their body is already covered with fur. Ten days after birth, the beavers begin to gnaw on small twigs and leaves that their dad brings them. For a whole month they try to keep the curious beavers in the hut. They know how to swim from birth, but they cannot dive at first - they are too light. The water pushes them out like a cork. If you don't know how to dive, you won't get back home, because the entrance is underwater.
26 slide. The forest needs beavers! Various forest animals come to beaver ponds to drink. Ducks and fish live here. If there is a forest fire, beaver ponds and canals block the path of the fire. Felled aspens and willows produce rich root growth. The bark and young branches of trees felled by beavers are eaten by moose, hares, and roe deer. It turns out that the beavers seem to arrange for them "dining room" .
Slide 27 The reserve has a nature museum, where you can learn a lot about the life of a beaver, as well as a beaver nursery, where everyone can look at live beavers. In separately standing house beaver you can not only watch a film about "king of rodents" , find its traces, but also identify animal fur by touch.
Fortunately, thanks to the reserve workers, the number of beavers has increased significantly. And now the beaver and his works can be seen not only on the territory of our reserve, but also along the banks of the rivers of his native land.
The beaver is often called the "king of rodents." Indeed, against the background of mice, rats, squirrels, gophers and other representatives of this most numerous, but short order of mammals, the beaver looks majestic, royal. The beaver's body length reaches 70 cm. 30 cm falls on the spade-shaped tail. And this beast weighs up to 30 kg. Beavers live long, up to 25 years.
The first miracle is beaver teeth. The tool of labor of the beast - the woodcutter - is unusually powerful incisors, of which there are a pair on each jaw. The beaver rests against the trunk with its upper incisors and cuts off the shavings with its lower incisors. On the outside, the animal has only a third of the length of its incisors, and the rest is securely fixed in the jaws. Therefore, the cutters can withstand the enormous pressure that occurs during operation.
More often, beavers cut down soft deciduous trees - aspen, poplar, and willows. However, they can handle even oak. Usually the animals cut down thin trees, but sometimes they also gnaw through powerful trunks that are a meter thick. It takes a beaver 2 minutes to fell an aspen tree with a diameter of 5-7 cm. On big trees they spend a whole night or several nights.
The second miracle is a beaver fur coat. During bathing, the beaver's skin does not get wet. What's the secret here? Chief of them - extraordinary fur density. Each square cm of a beaver's body contains 12 thousand hairs on its back and 23 thousand on its abdomen. In winter the fur is even thicker. The shape of the undercoat hairs is unusual. They are thickened in the middle and fit tightly to each other. And the guard hairs are expanded at the top, so that they form a “roof” over the undercoat. The entire fur coat is covered with fatty lubricant, which is formed in the sebaceous glands in the back of the animal’s body.
The third miracle is the beaver tail. The beaver's tail is bare and covered with horny scales. But these are not the same scales that cover the body of the fish, but special thickenings of the skin. Without a tail, the animal would not be able to gnaw trees, because the tail is its main support when working. A beaver could not swim so well anyway, because its tail serves as both an oar and a rudder. The tail protects the animal from overheating. The whole body is dressed in a warm fur coat, and only thanks to the bare tail, excess heat is transferred to the environment.
The fourth and fifth miracles are beaver lodges and dams. Huts - beaver dwellings - are built from branches and twigs, which are held together with clay and silt. From the outside the hut looks like a pile of brushwood, but in fact it is very durable. Beavers do not just stack branches, but weave them together. The entrance to the hut is always located under water. There are often 2 entrances. Beavers live in the hut for many years and constantly expand it. The height of the huts is 2-3 meters. But multi-storey palaces five to six meters high are known. The record is 13 meters.
The sixth miracle is beavers. Beavers live in families; they form married couples for life. Every spring, 2 to 5 beaver cubs appear. They live with their parents for two years and only in the third year do they start their own families. The beaver family consists of individuals.
Newly born beavers are sighted, covered with fur, and weigh up to 700 grams. After a day or two, the kids are already swimming, although they cannot dive yet - they are too light. They try their best, but the water pushes them out like a cork. Mothers feed their young with milk, but after 3 weeks the nimble babies begin to eat aquatic greens: cattail, reed, reeds, whitewing, egg capsule, water lily, etc.
The seventh miracle - the beavers are returning! In the first years of Soviet power, the state took beavers under its protection. Hunting them was completely prohibited. Employees of the Voronezh Nature Reserve carried out especially great work to save beavers. When the reserve was organized, only 30–40 beavers lived there. But after some time there were so many animals that it became possible to resettle them throughout the country. Now about 4 thousand animals have already been removed from the reserve. And in total there are now 200 - 220 thousand beavers living in our country! Moreover, their regulated fishing has been going on for two decades.
People, fortunately, realized in time that these wonderful animals were in mortal danger. They understood and managed to preserve them. After all, the forest really needs beavers; it’s not for nothing that they are called “guardians of the waters”: beaver dams ensure a gradual decline spring water from small rivers, and this preserves forests and water meadows. Beaver ponds and canals stop forest fires. Aspens and willows, which beavers cut down, produce rich growth. And in the spring, when rivers flood, many animals escape by climbing onto beaver lodges and dams. “Little forest people,” that’s what the Indians called beavers.
