Oviparous - belong to the class mammals, subclass cloacal. Among all known vertebrates, monotremes are the most primitive. The detachment got its name due to the presence of a special characteristic among the representatives. Oviparous ones have not yet adapted to live birth and lay eggs to reproduce offspring, and after the babies are released, they feed them with milk.

Biologists believe that monotremes emerged from reptiles, as an offshoot from a group of mammals, even before the birth of marsupials and placental animals.

Platypus - representative of oviparous

The structure of the skeleton of the limbs, head section, organs of the circulatory system, respiration of primordial animals and reptiles is similar. In the fossils Mesozoic era revealed the remains of oviparous. Monotremes then inhabited the territory of Australia, and later occupied the South American expanses and Antarctica.

Today, the first animals can be found only in Australia and the islands located nearby.

The origin and diversity of mammals. Egg-laying and true beasts.

The ancestors of mammals are reptiles of the Paleozoic. This fact confirms the similarity in the structure of reptiles and mammals, especially at the stages of embryogenesis.

In the Permian period, a group of theriodonts, the ancestors of modern mammals, was formed. Their teeth were placed in the recesses of the jaw. Most of the animals had a bony palate.

However, the conditions environment, formed in the Mesozoic era, contributed to the development of reptiles and they became the dominant group of animals. But the Mesozoic climate soon changed dramatically and the reptiles were unable to adapt to the new conditions, and mammals occupied the main niche of the animal world.

The mammalian class is divided into 2 subclasses:

• Subclass of First Beasts or Monotremes;
• subclass Real beasts.

Real animals and monotremes are united by a number of signs: hairy or acicular outer cover, mammary glands, hard palate. Also, the first animals have common characteristics with reptiles and birds: the presence of a cloaca, laying eggs, a similar structure of the skeleton.

Detachment One-pass - general characteristics

Echidna is a representative of monotremes

Oviparous - animals are not large sizes with a body flattened from top to bottom, short limbs with large claws and a leathery beak. They have small eyes, short tail... In oviparous, the external auricle is not developed.

Only representatives of the platypus family have teeth and they look like flat plates equipped with projections along the edge. The stomach is only for storing food, the intestines are responsible for digesting food. Salivary glands very developed, large, the stomach passes into the cecum, which, together with the urogenital sinus, flows into the cloaca.

First animals do not have a real uterus and placenta. Reproduction by laying eggs, there is little yolk in them, and the shell includes keratin. The mammary glands have many ducts that open on the ventral side in special glandular fields, since there are no nipples in monotremes.

Body temperature can vary: it does not rise above 36 ° C, but with a significant cold snap it can drop to 25 ° C. Echidnas and platypuses do not make sounds, as they are deprived of vocal cords... The life expectancy of echidna is about 30 years, platypuses - about 10. They inhabit forests, steppes with shrubs and are even found in highlands(at an altitude of up to 2500m.).

Oviparous representatives have poisonous glands. On the hind limbs there is a bone spur through which flows poisonous secret... The poison is potent, in many animals it provokes a malfunction of the vital important organs, for a person is also dangerous - it causes in the place of defeat severe pain and extensive swelling.

Trapping and hunting representatives of the detachment is prohibited, since they are listed in the Red Book due to the threat of extinction.

Platypus and Echidna

Platypus and echidna are oviparous, mammals, the only representatives detachment.

A small animal about 30-40cm long (body), tail up to 15cm, weighing 2kg. Males are always larger than females. He lives near water bodies.

Five-toed limbs are well adapted for digging the ground; on the coast, platypuses dig holes for themselves about 10 meters in length, equipping them for later life(one entrance is underwater, the other is a couple of meters above the water level). The head is equipped with a beak like a duck (hence the name of the animal).

Platypuses are in the water for 10 hours, where they get food: aquatic vegetation, worms, crustaceans and molluscs. Swimming membranes between the toes on the front legs (on the hind legs are almost undeveloped) allow the platypus to swim well and quickly. When the animal dives under water, the eyes and ear openings are closed, however, the platypus can navigate in the water space thanks to the sensitive nerve endings on the beak. It even possesses electroreception.

Platypuses bear cubs for a month and give birth to one to three eggs. First, the female incubates them for 10 days, and then feeds them with milk for about 4 months, and at the age of 5 months the platypuses, already capable of independent life, leave the hole.

TO oviparous mammal also applies echidna, found in forests, by outward appearance looks like a hedgehog. To obtain food, the echidna digs the ground with powerful claws and, with the help of a long and sticky tongue, receives the necessary food (termites, ants).

The body is covered with thorns that protect it from predators; when danger approaches, the echidna curls up into a ball and becomes inaccessible to enemies. The female weighs approximately 5kg and lays an egg weighing 2g. The echidna hides the egg in a bag formed by a leathery fold in the abdominal region and carries it, warming it with its warmth, for two weeks. A newborn cub is born with a weight of 0.5 g, continues to live in the mother's pouch, where it is fed with milk.

After 1.5 months, the echidna leaves the bag, but continues to live in a hole under the protection of its mother. After 7-8 months, the baby is already able to find food himself and differs from adult only in size.

1. Let us explain the statement.
Yes, that's right. Bearing pups, live birth, feeding on milk, caring for offspring ensure the best safety of young animals in a varied environment.

2. Let's name the representatives of the class Mammals.
Dwarf shrew - 4 cm.
Blue whale - up to 33 cm.

3. We list specific features mammals.
Two pairs of five-fingered limbs; cervical spine - from 7 vertebrae; teeth differ in structure and function; there are milk, sweat, glands; the body is covered with wool; four-chambered heart; developed cerebral cortex and sensory organs; the heart is four-chambered.

4. Let's write an answer about the size of mammalian teeth.
Crocodiles have teeth that are different only in size, while in mammals they differ not only in size, but also in the functions they perform: there are incisors, canines, molars.

Detachment One-pass

1. Define common features oviparous and reptiles.
Body temperature is inconsistent. They reproduce by laying eggs. The eggs are covered with a keratinized shell, reminiscent of a reptile's shell.

2. Let's define an animal.
Lives in Australia. Its body is covered with needles, its beak is tubular. Body temperature is unstable - up to 30 ° C. It reproduces by eggs, which it bears in a leathery pouch on its belly. Sharp claws are used to dig holes.
Answer: echidna.

3. Let us explain why the first beasts are protected.
The First Beasts are very rare animals.

Marsupial squad

1. Let's point out the peculiarity of the life cycle.
Marsupials have a special fold of skin on their belly in the form of a pocket, where newborns are placed.

2. Let's fill in the table.
Habitat:
1. lives in trees;
2. lives on eucalyptus trees;
3. lives in the soil, digs holes;
4. lives near streams and rivers.
Diet:
A. feeds on small fish and aquatic invertebrates;
B. feeds on insects, larvae, and worms;
V. feeds on eucalyptus leaves;
G. feeds on birds and rodents;
D. eats plant and animal food.

Squad Insectivores

1. Let's name the representatives of the detachment.
Shrew, mole, desman.

2. Let's name the smallest and largest representative of the detachment.
Shrew crumb - up to 4 cm.
Common desman - up to 22 cm.

3. We indicate the value of the elongated muzzle and proboscis.
With their help, Insectivores catch insects from their burrows and tunnels.

4. Let's write an animal that lives in the soil.
Mole.

Bats squad

1. Let's write the general in the way of movement.
Birds and bats are capable of long flapping flight.

2. Let's name two suborders of bats.
1. Bats
2. Bats.

3. Let us indicate the orientation method.
Bats are capable of echolocation. In flight, they emit high frequency sounds (ultrasounds). Reflected from obstacles sound waves caught by large auricles bats... The distance to the object is determined by the nature of the reflected sound of the mouse.

4. Let us explain why humans rarely meet bats.
Bats are active at night.

5. Let's write the answer about the decrease in body temperature of bats.
Their metabolism decreases and energy expenditure slows down.

6. Let's sign the drawings.

Bats squad. View of the Red nocturnal.

Squad Insectivores. Desman type.

Detachment One-pass. Platypus view.

Squad Marsupials. View of the marsupial wolf.

Squad Insectivores. View of the Mole.

Oviparous and marsupial mammals.

Oviparous or primitive beasts - relict forms, the distribution of which is now limited to Australia and New Guinea. They are brought together with reptiles following signs:

1) the laying of large, yolk-rich eggs, which are then hatched in a bag (in an echidna) or hatched (in a platypus);

2) shoulder girdle with coracoid;

3) cloaca.

Signs of mammals:

1) hairline;

2) homeothermy (not yet perfect);

3) the mammary glands;

4) heterogamety of males.

Marsupials give birth to underdeveloped cubs (short pregnancy), which are worn out, fed with milk in a bag or between the skin folds on the belly. They are currently only found in Australia and South America; only one less specialized species, the North American possum, settled and North America... A variety of marsupials were able to survive only where geographical isolation saved them from competition with placental mammals,

In Australia, predators are known among marsupials ( marsupial wolf, marsupial marten), insectivores (marsupial mole, marsupial shrew, marsupial anteater marsupial flying squirrel), fruit and deciduous (tree kangaroos, koala) and, finally, large herbivores (kangaroos). This adaptive radiation clearly demonstrates how specialized marsupials in Australia have mastered all of those ecological niches, which on other continents were occupied by placentals.

68 Insectivores and bats mammals.

Insectivores usually a long head and an elongated muzzle that ends in a proboscis. Their bodies are short. Some insectivores are covered with soft silky hair, others - with hard needles. Many of them live underground, some in the water and some in trees.

Some insectivores spend the winter in hibernation, some continue their active way of life in the winter under the snow or in the water under the ice, or in underground tunnels. Many species of insectivores are useful for Agriculture... They exterminate harmful insects, their larvae, worms, snails and even small rodents. There are species that provide valuable varieties of furs.

Insectivores are found mostly in temperate countries northern hemisphere, especially in China. In South America and Australia, there are no insectivores at all.

Distinctive bats sign- These are a kind of wings that were formed from the front limbs. Between very elongated fingers, they have a thin leather membrane stretched, adjacent to the sides of the body. The same membrane is stretched between the Hind Legs and the tail. Thanks to the wings the bats seem to be rather large animals, in fact, many of them belong to the smallest mammals.

Bats have a remarkably developed sense of touch. Even when flying, they are guided not by sight, but mainly by touch. Scientists did such experiments: they pulled many threads up and down the room and let the bat fly, and it flew without touching a single thread.

Then they put an English plaster over her eyes and even her ears and let her fly again. Blinded and deaf, the bat flew between the threads with the same speed and confidence as before, and did not touch a single thread.

Bats, with the exception of some species, hibernate in winter. Before that, they get very fat; fat lies in layers between muscles and skin and on the viscera. There is so much fat that in some species its weight exceeds the weight of the animal itself. Due to this fat, as well as other body substances, the bat feeds during hibernation. During this time, she loses one fifth to sixth of her weight.

69. Lagomorph mammals and rodents.

Gnawing mammals- a group that includes mice, rats, rabbits - are extremely lucky animals, found in almost all habitats except the seas. Most of them live on the ground, although there are many rodents - such as squirrels - that are good at climbing trees and find refuge there. Others - like beavers and some voles - live near or even in fresh water. Many use burrows only as a refuge, but mole rats and similar species are adapted to life underground and almost never come to the surface.

Lagomorphs - hares, rabbits, hay stands - live a life similar to rodents. Key representatives. The order of rodents (1600 species) is the most numerous among mammals, it includes several families of animals. Group of squirrels (377 species) with marmots and beavers. Porcupine group (188 species) with guinea pigs and chinchillas. A group of mice (1137 species) with rats and hamsters. The order of lagomorphs (58 species) includes rabbits, hares, pikas. Teeth and jaws. Rodents have a pair of large incisor teeth at the top and bottom.

Reproduction. Many gnawing mammals produce numerous offspring. In fact, they do not breed very often and not in such a large number. While some animals produce 17 cubs at once, the number 4 is most typical for rodents and lagomorphs. However, the cubs themselves are able to reproduce already in early age... In species such as mice, gestation lasts only a few weeks, and the new generation can produce droppings by itself in less than a year. Rabbits reproduce no less quickly. Dwellings Some of the rodents find shelter in hollows. Others build a nest from twigs, like some squirrels, or from grasses and bark, like field hamsters. Rodent houses are mostly not very skillful, but Australian rats build large waterproof structures. Such dwellings may have several compartments, including a storage room and a latrine. But the best terrestrial houses are created by beavers.

70. Carnivorous mammals.

A detachment of predatory mammals unites the most different kinds animals - from a huge lion to a tiny weasel. In this detachment we meet a cat and a hyena, a civet, a dog, a bear and a marten.

But all these various animals are armed with lips and claws to attack other animals, the meat of which they eat. All of them are carnivorous predators, and the better their body is adapted to meat food, the better their so-called carnivorous teeth are developed and the fewer teeth remain behind the carnivores. In the family of bears, which also eat plant food, the carnivorous tooth is almost indistinguishable from the tuberous teeth lying behind it, with blunt tubercles and a wide chewing surface. Dogs have two teeth behind the carnivorous teeth in the upper and lower jaws. Cats have only one small molar behind the carnivorous, or carnivorous, tooth in the upper jaw, and this tooth in the lower jaw is the last. In connection with the great development of the chewing muscles on the turtles of carnivorous mammals, the ridges are usually strongly protruded. The brain is well developed, the hemispheres are covered with convolutions. In some species, the anal glands secrete a smelly fluid in the anus. This liquid serves to protect against enemies or to lure prey. Sometimes the glands secrete a fatty mass to lubricate the fur. Both in general disposition of the body and in gait carnivorous mammals very different. Among them there are plantigrade, toe and transitional between those and others. Most species have a well-developed tail. Predatory quickly run on the ground, many of them climb trees perfectly; some species have adapted to life in the water, and in connection with this, their general appearance has changed.

The most valuable fur-bearing animals belong to the order of carnivores.

71 Pinnipeds and Cetaceans.

Their body shape is streamlined, torpedo-like.
The skin has no hair, the skin glands are absent.
The forelimbs are modified into flippers, and the hindlimbs are absent.
Cetaceans move with the help of a powerful tail with a large tail fin. Most noticeable external difference whale from fish - this is the horizontal position of the tail fin. It allows cetaceans to move in a wavy line that provides communication with atmospheric air.
They breathe, like all animals, with the help of their lungs. In one breath, the lungs of whales are filled with air in a volume of up to 5,000 to 14,000 liters, which allows the animals to stay under water for 15 to 90 minutes.
Cetaceans see relatively well, hearing is even better developed. Cetaceans have the ability to echolocate and easily navigate even great depth... Many of the cetaceans migrate, swimming up to 10,000 km.
A layer of fat 18-50 cm thick accumulates under the skin of cetaceans. ensuring the constancy of body temperature and reducing the specific gravity.

FINNOLOGY: Animals of medium and large size: from 1.2 to 6 m in length and weighing from 40 to 3500 kg.
The body is elongated, fusiform, streamlined, with a relatively small head and a thick neck.
The teeth are sharp and serve to seize prey, feed on fish, crustaceans, molluscs.
The ear openings are closed when immersed in water.
The limbs are short, their shoulder and femoral sections are hidden in the body, and the paws visible from the outside have transformed into a kind of fins - flippers. The front flippers, like the paired fins of fish, control turns, and when moving on land or ice, they allow you to crawl, clinging to the roughness of the ground with their claws. The hind limbs always remain stretched back, in their outlines representing some semblance of a fish tail, they do not take part in movement on land, and in the water they serve as a powerful organ of movement.
Have a hairline. In the hairline, there is a transition from thick fur with dense down in fur seals to sparsely coarse hairs in walruses.
Subcutaneous fat layer about 10 cm.
Pinnipeds - semi-aquatic mammals... Most of the time they spend in water, where they get their own food, rest on land, reproduce, feed offspring.

72. Proboscids, artiodactyls and equid mammals.

In all equids, the third toe is especially developed. They lean on it when walking.

The equids do not have canines, or their canines are poorly developed, there are special enamel folds on the molars, and there are almost always incisors in both jaws. The stomach of equids is simple, and not complex, like that of ruminants. The liver does not have a gallbladder.

This whole squad is divided into three families.: three-toed rhinoceroses, one-toed horses and tapirs with four toes on the front and three toes on the back.

To the detachment of each leg, either two fingers - the third and fourth, or four fingers, but then the third and fourth are more developed than the lateral ones - the second and fifth. To better understand the large number and variety of species of these animals, they are divided into groups. There are two groups: 1) non-ruminant, or pig-like; they have, in addition to the two main fingers, the second and fifth relatively well developed; 2) two-hoofed, or ruminants; these second and fifth fingers are either underdeveloped or nonexistent. Ruminants differ from other ungulates and from all other mammals also by the fact that they chew food twice (chewing gum).

The pig-like group includes pigs and hippos; to the group of ruminants - the rest numerous types artiodactyls.

All artiodactyls feed exclusively or mainly plant food.

Question 1. Why can it be argued that oviparous, marsupials and insectivores are very ancient and most primitive mammals?

Oviparous are ancient mammals that have a number of primitive characteristics characteristic of reptiles, from which they originate. Their body temperature is unstable (from 22 to 25 ° C for the platypus or 30 ° C for the echidna). They reproduce by laying eggs, which they incubate (platypus) or carry in a leathery bag on their belly (echidna). The eggs are covered with a keratinized shell, reminiscent of the shell of reptile eggs.

Marsupials already bear cubs inside the body, but for a very short time (which is associated with a primitive device compared to higher mammals, their reproductive systems). Cubs are born underdeveloped. Their further development leaks in the bag.

Insectivores are also considered ancient and rather primitive mammals, as they are able to hibernate ( characteristic feature cold-blooded reptiles) are rather small in size, their dental apparatus consists of a large number of teeth (for example, hedgehogs have 36), which have the same structure, and other primitive signs.

Question 2. Why oviparous and marsupials survived mainly in Australia and adjacent islands?

Australia lost contact with other continents before more progressive groups of mammals appeared there. Therefore, the highest and prosperous group of the class of mammals on this continent remained the marsupials, which somewhat pushed aside the oviparous, but continued to coexist with them.

Question 3. Why is it necessary to protect rare oviparous, marsupial, insectivorous and bats?

These orders of mammals are very ancient and have many primitive traits that negatively affect the survival of these animals in competitive habitats. Therefore, a person must take over their protection.

31. Class Mammals, or Beasts. Orders: Monotremes, Marsupials, Insectivorous, Bats

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The topic of our lesson is "Class Mammals, or Beasts." The purpose of the lesson is to make a brief description of the Mammals class and its four orders: Monotremes, Marsupials, Insectivores and Bats.

2. Characteristics of the class Mammals

In the previous lesson, we ended our conversation about birds. Now let's make a brief description of the Mammals class. The class got its name because the females feed their young with milk (Fig. 1). Milk is produced by the mammary glands, which are derived from the sweat glands.

Rice. 1. Feeding cubs

Viviparity, feeding with milk and caring for the offspring ensures the best safety of young animals under a wide variety of circumstances, but all this is possible only with a small number of young.

Mammals, or animals, appeared 160-170 million years ago. The mammals' ancestors were about the size of a rat, and most likely ate insects.

Just like birds, mammals have a constant body temperature, they are warm-blooded animals (Fig. 2). Hair is characteristic of mammals. If the feathers of birds are similar in structure and development to the scales of reptiles, then the hair of mammals is a unique formation.

Rice. 2. Warm-bloodedness allows animals to survive at low temperatures

The appearance and size of mammals is very diverse. There are 2 pairs of 5-finger limbs. The cervical spine, consisting of 7 vertebrae, connects the head to the body in a very flexible way. On the upper and lower jaws, there are specialized, that is, different in structure and function, teeth.

All mammals are characterized by a high level of development of the nervous system, especially the cerebral cortex and sensory organs are developed.

The circulatory system is closed, the heart is four-chambered. Blood moves in two circles of blood circulation, venous and arterial do not mix (Fig. 3).

Rice. 3. The circulatory system of mammals: large and small circle of blood circulation

There are more than 5.5 thousand species of modern mammals. They have spread widely across the globe. They live in a wide variety of conditions - at the poles of the Earth, in soil, in sea and fresh water, some have mastered flight.

The class mammals is subdivided into subclasses: Oviparous, or first animals, and True animals.

3. Subclass Oviparous

The subclass Oviparous, or the First Beast, has only five species, among them the platypus, 2 species of echidnas and 3 species of prochidnas (Fig. 4). They live in Australia, Tasmania and New Guinea.

Rice. 4. First Beasts

This is a very ancient order of mammals with many very primitive characteristics. The body temperature is not constant - from 22 to 25 degrees for the platypus and about 30 degrees for the echidnas.

They reproduce by laying eggs. They incubate eggs, like a platypus, or they hatch in a leathery bag on their belly, like an echidna. The eggs are covered with keratinized shells.

The body of the platypus is covered with thick hair, the head ends with a keratinized lamellar beak without teeth. The front and hind limbs of the platypus have leathery membranes, with the help of which it swims and dives. Adult platypuses feed on a variety of aquatic invertebrates (Figure 5).

Rice. 5. Platypus

The body of the echidna (Fig. 6) is covered with needles, the beak is tubular. The female lays eggs in a burrow and carries them in a leathery pouch on her belly for about 9-10 days. Sharp claws are used by monotremes to dig holes. All members of the detachment are rare animals, they are subject to protection.

Rice. 6. Echidna

4. Subclass True Beasts

Order Marsupials (Fig. 7). There are about 250 species of modern marsupial mammals. They live in Australia, New Guinea and nearby islands. Several species are also found in America.

Rice. 7. Marsupials

The detachment received its name for the presence on the belly of a special leathery fold in the form of a pocket or bag, in which newborns are placed. The gestation period in marsupials is very short. Cubs are born small, blind, helpless, virtually underdeveloped (Fig. 8).

Rice. 8. Newborn marsupial

Their further development takes place in the bag. In large species of kangaroo, the length of a newborn is only about 25 mm, in small species of marsupials - only about 7 mm. The weight of a newborn calf for various representatives of the detachment is from 0.6 to 5.5 g.

In the pouch, the cub sticks to the nipple of the mammary gland and spends there up to several months. Probably the most famous of the marsupials, the kangaroo (Fig. 9), feeds on plant foods and moves by jumping.

Rice. 9. Kangaroo

The convergence of some marsupials with the higher animals well known to us is amazing. So, the marsupial mole (Fig. 10) lives in the soil, digs holes, and feeds on worms and insects. The marsupial cat is a woody predator (Fig. 11).

Rice. 10. Marsupial mole

Rice. 11. Marsupial cat

Despite their great external similarity, they are completely unrelated to ordinary cats and moles. The koala marsupial bear lives on eucalyptus trees and feeds exclusively on their leaves (Fig. 12).

Rice. 12. Koala

The North American possum, about the size of a cat, eats both animal and plant foods. Its close relative, the water possum, has leathery membranes on its legs, it swims and dives well, and feeds on small fish and aquatic invertebrates (Fig. 13).

Rice. 13. Possum

5. Placental, or Higher Beasts

They are characterized by the presence of the placenta - a special organ that serves to feed the developing embryo - and the birth of relatively developed babies (Fig. 14).

Rice. 14. Higher beasts

Despite this name, representatives of the order can feed on both insects and various other small animals. Representatives of the order are animals of medium and small size, with an elongated muzzle ending in a proboscis (Fig. 15).

6. Squad Insectivores

Rice. 15. Insectivores

This order is considered ancient, all insectivores, except for hedgehogs, have a short-haired coat. They are very widespread; they are absent only in Australia, Antarctica and South America.

The total number of insectivorous species is about 400. Insectivores include hedgehogs, moles, shrews, desman and others. The largest representative of the order is the desman (Fig. 16), up to 22 cm long, with a long, laterally compressed scaly tail.

Rice. 16. Desman

The smallest representative is a crumb shrew up to 4 cm long (Fig. 17).

Rice. 17. Shrew-crumb

Hedgehogs live in deciduous and mixed forests, in the forest-steppe and steppe regions of Europe. The back and sides of the hedgehog are covered with sharp needles; at the moment of danger, it curls up into a ball (Fig. 18).

The paws of the animal are equipped with sharp claws. It is active at twilight and at night, feeding on various invertebrates, as well as frogs, lizards, snakes, and small birds. Able to destroy nests. Hedgehogs destroy many pests of agriculture, as well as poisonous snakes, so they can be beneficial to humans.

Rice. 18. Hedgehogs

In winter, hedgehogs hibernate; in spring, the female gives birth to 3 to 8 cubs (Fig. 19). Hedgehogs become sexually mature in the 2nd year of life. The European hedgehog can be the host of ixodid ticks, a carrier of diseases dangerous to humans and domestic animals. On one hedgehog there are up to 3 thousand ticks.

Rice. 19. Hedgehog cubs

The desman has adapted to the aquatic lifestyle (Fig. 20). Her hind limbs have swimming membranes. The coat is dense, dense with a soft undercoat. The animal hunts at night and at dusk, lives near water in holes.

Rice. 20. Desman

The desman feeds on both plant and animal food, which it looks for in the water. Desman reproduces in the spring, in the litter from 1 to 5 cubs, they grow quickly. At the age of one and a half months, they are able to leave the nest and lead an independent lifestyle. The desman is a rare species; in many territories it has been supplanted by the imported muskrat.

7. Order Bats

Includes about 1200 species, the second largest order of mammals after rodents (Fig. 21). They are systematically close to insectivores. Bats have mastered the air, they are capable of long flapping flight.

Rice. 21. Bats

They live almost all over the world, with the exception of the polar regions. The largest representatives with a wingspan of up to 180 cm (Fig. 22) live in the tropics of Asia, Australia and Africa and belong to the suborder Fruit bats. They feed on juicy fruits.

Rice. 22. Bats

Smaller representatives of bats belong to the suborder of bats. All bats are united by the presence of a leathery membrane that forms a wing between the fore and hind limbs. The tail is also usually covered with a membrane.

The first toe of the forelimbs is free and is used to climb cavern walls, tree bark, and so on. When resting, they hang horizontally or vertically upside down (Fig. 23). In this position, they sleep, give birth to cubs, some hibernate like that.

Rice. 23. Position in space

During sleep, the body temperature drops significantly, blood circulation and respiration slow down. Bats are active at dusk and at night. Most species catch insects on the fly, but some feed on soft fruits, fish, or even the blood of warm-blooded animals.

The eyesight of bats is poorly developed, but they orient themselves well in the dark. The fact is that bats are capable of so-called echolocation. In flight, they constantly emit high frequency sounds, ultrasounds. Sounds reflected from obstacles are captured by the animals' large and complex auricles.

By the nature of the reflected sound, bats are able to calculate the distance to objects, and they never run into obstacles. Most of the bats hibernate in warm countries, and a smaller part in shelters. At the same time, their body temperature can drop to almost 0 degrees.

Bats breed in summer, females usually bring one, naked and blind cubs. Clinging to the mother's body, covered with warm fur, he does not let her go up to 2 months, even during the hunt (Fig. 24).

Rice. 24. Baby Bat

Exterminating a large number of insects, pests and mosquitoes, bats bring tangible benefits to humans; they must be attracted to human habitation, creating shelters for them and protecting their habitats.

The origin of mammals

Among the reptiles of the subclass Beast-like, by the Permian period, the order Beast-toothed was formed. In these animals, instead of identical teeth characteristic of reptiles, incisors, canines and molars appeared (Fig. 25).

Rice. 25. The structure of the teeth

The structure of their jaws was reminiscent of the structure of the jaws of mammals. By the end of the Triassic period, the animal-toothed was completely supplanted by other reptiles.

All of their large representatives became extinct, but already in the Triassic period some group of small animal-toothed species, which probably lived in dense thickets, gradually acquired the features of a more aggressive organization and gave rise to mammals.

Mammal records

The body length of mammals is from 4 centimeters in the pygmy shrew to 33 meters in the blue whale (Fig. 26, 27). Body weight - from 1.5 grams to 150 tons.

Rice. 26. Dwarf shrew

Rice. 27. Blue whale

The slowest mammals are sloths (Fig. 28), they move only when very necessary, and still slowly, hence the name.

Rice. 28. Sloth

The fastest mammal is the cheetah, at short distances it can reach speeds of up to 115 km / h (Fig. 29).

Rice. 29. Cheetah

Bloodthirsty hedgehogs

Hedgehogs bring tangible benefits, destroying pests, including in orchards and vegetable gardens. An ordinary hedgehog eats up to 200 grams of insects in one night.

In New Zealand, in the absence of natural predators, they themselves turned into pests, destroying local insects, molluscs and ruining bird clutches. The example of hedgehogs clearly shows how alien to nature the principle of humanity.

Hedgehogs love to eat small reptiles, including snakes, even venomous ones. They are reliably protected from bites by their needles and often begin to eat the snake from the middle of the body or even from the tail while alive.

Vampires

Now we will talk about vampires, but not about those in the films, but about the real ones, these are 3 types of bats that live in tropical America. They feed on the blood of any warm-blooded animals.

Their saliva contains substances that relieve pain and prevent blood clotting. Bleeding after a bite can last up to 8 hours, but this is not the main problem.

The fact is that vampires carry rabies and other dangerous infections. Vampires themselves do not die from rabies, they are the only mammals that are immune to this virus. Vampires also brought benefits: on the basis of their salivary enzyme, which prevents blood clotting in mammals, an anti-stroke drug was created.

7. Discuss with friends and family the importance of mammals in nature and economy.