What animal is a mammal. Class Mammals, or animals. digestive system. breath. origin of mammals. the importance of mammals and the protection of useful animals. The circulatory system of a mammal

IN primary school need to create different presentations that are designed to develop children. One of the topics of such a presentation is about what animals are mammals. Consider the main representatives.

Presentation on the theme of mammals for children

Bats and bears, monkeys and moles, kangaroos and whales - all these animals belong to the group of mammals, man is also a mammal, as well as most domestic and farm animals - cats, dogs, cows, sheep, goats, etc. In total, there are about 4,500 species of mammals on our planet.

strange mammal

This amazing mammal — giant anteater- lives in the forests of South America. It feeds exclusively on ants and termites. The anteater breaks insect nests with sharp claws and licks the prey with a long sticky tongue that stretches 60 centimeters in length!

Whales, dolphins and seals are aquatic mammals. Unlike other animals, they do not have hair, and a thick layer of subcutaneous fat protects them from hypothermia.

miniature creatures

One of the smallest mammals -. This Mexican leaf-bearer, for example, is no larger than a bumblebee (about 2 centimeters).

Good girl!

The brain of mammals is much better developed than that of all other animals. The smartest living creatures after humans are monkeys. Some of them use the simplest tools: for example, chimpanzees get termites from their nests with a stick.

For comparison

The blue whale is the largest mammal on Earth. Even such a land giant as an elephant looks very small in comparison (see the picture below).

MAMMALS AND THEIR BABY

Mammals are the only animals that feed their young with milk. Babies are born completely helpless and require constant care. A baby chimpanzee, for example, stays with its mother until the age of six.

baby giant

At blue whale, the largest mammal on Earth, the largest cub is born: the length of the newborn reaches 6-8 meters. The female whale has very nutritious milk, so the baby grows quickly.

oviparous mammals

Some mammals lay eggs, which then hatch into young. One of these unusual animals is living in Australia. It has a bird-like beak and webbed feet. Platypus babies suck milk by licking it off their mother's fur.

marsupials

Kangaroo and koala belong to marsupials . Their cubs are born incompletely formed and continue to develop in a special bag on the mother's stomach. Here the babies suckle milk and stay until they can take care of themselves.

1. A newborn kangaroo gets into your pocket

2. In his pocket he sucks mother's milk

3. The baby is in the pocket until it is covered with hair and can not take care of itself

Caring for offspring

Most mammals take care of their young for some time after birth. Babies, like this cheetah, are usually completely dependent on their mother - she feeds them and protects them. When the cubs grow up, the mother teaches them to hunt and avoid danger.

This material can be used when answering children's questions about animals, as well as about which animals are mammals. In elementary school, this material will be like a presentation on the topic of mammals. Children, having become acquainted with this concept as mammals, presenting their presentation in the class, will have to tell in their own words everything that they have learned. Therefore, do not forget to give your child not only to read our article, but also to retell what he will remember.

Mammals are the most highly organized and youngest class of animals, which are characterized by the following features:

• hairline
• skin glands
• warm-bloodedness
• constant body temperature
• developed cerebral cortex
• live birth
• care of offspring
• complex behavior.

All this allowed mammals to win a dominant position in the animal world. They live in all environments: on land, in soil, in water, in the air, on trees, in all natural areas.

Ecological types of mammals ( life forms) are determined by their habitat: aquatic and semi-aquatic have a streamlined fish-like body shape, flippers or membranes on their paws; ungulates living in open areas have high slender legs, a dense body, and a long movable neck. Therefore, among representatives of different subclasses, orders, families, there may be similar life forms due to the same living conditions. This phenomenon of nature is called convergence, and signs of similarity are called homologous.

highly developed nervous system allows mammals to better adapt to environmental conditions and more fully use Natural resources when obtaining food, when protecting from enemies, when arranging holes, shelters.

The transfer of experience, the training of young animals, and the foresight of the course of many events made it possible for animals to better preserve their offspring and occupy new territories.

Their population structure is different: some consist of living alone or in families in a permanent place, others roam in a herd or flock. Plays a big role a complex system subordination, when there is a selection for the best organization of the herd or pack.

In food chains, mammals also occupy different position: some are primary consumers of plant foods (consumers of the 1st order), others are carnivorous, peaceful (insect- and plankton-eating - consumers of the 2nd order), others are predatory (attacking large active prey - consumers of the 2nd and 3rd order). Mixed nutrition is characteristic of primates, predators and rodents. The relationship of animals with plants is very close, which, on the one hand, are an object of eating (in this case, fruits and seeds often spread), and on the other hand, they protect themselves from them with the help of thorns, thorns, unpleasant odor, bitter taste.

Of the entire animal world, man is more closely associated with mammals: 15 species are domestic animals, in addition, 20 species are fur-bearing animals bred in cages, as well as laboratory animals (mice, rats, guinea pigs, etc.). Domestication continues at the present time: new breeds are bred and old ones are improved by hybridization with wild animals.

An important role in the human economy is played by hunting and sea fishing, acclimatization of animals from other continents.

At the same time, there are harmful animals that attack humans and domestic animals, carriers of diseases, pests of crops, gardens, and food supplies. To reduce the negative impact of these animals on nature and human economy, they study the structure of their populations, population dynamics, food resources - all these data are entered into a computer, as a result of which they receive a forecast for the future, develop recommendations that determine ways and means of influencing the population in order to limit her harmfulness.

The number of mammal species under the influence of human activity is constantly declining as a result of hunting, the destruction of predators, the destruction of habitats for wild animals, the protection of agricultural plants from rodents (treatment of fields with pesticides), forest and steppe fires, etc.

The Red Book of the USSR (1984) lists 54 species and 40 subspecies of animals. For their protection, reserves, wildlife sanctuaries, National parks, their breeding is organized, hunting and fishing are prohibited. Thanks to these measures, bison, kulan, Bukhara deer, tiger, eastern leopard, goral were saved from extinction; the number of saiga, sable, and beaver has been restored.

In the modern fauna there are 4000-4500 species of mammals, including within Russia - 359 species, in Ukraine - 101. Mammals are common on all continents, with the exception of Antarctica, in terrestrial, marine and freshwater biocenoses. Some species actively fly in the air, others live in the soil. Most species live in various terrestrial biocenoses. With regard to adaptation to life in different conditions the external appearance of these animals is very different, but they differ sharply from all other features of the internal and external structure.

Class characteristic

Mammals, or animals, represent the highest class of vertebrates, whose organs, especially the forebrain cortex, have reached the highest differentiation at the present stage of development.

Thanks to the progressive development of the central nervous system, warm-bloodedness, the presence of hair, bearing cubs in the mother's body and feeding them with milk, mammals won the competition with reptiles and other vertebrates and firmly conquered not only land, but also other habitats.

body integuments. Like all vertebrates, mammalian skin consists of a multi-layered epidermis and corium. Outside, the body is covered with the epidermis, the upper stratum corneum in the form of separate dead cells constantly disappears. The renewal of the epidermis occurs due to cell division of the Malpighian layer. The corium is built from fibrous connective tissue, the deep layers of which (the so-called subcutaneous tissue) contain fat cells. In addition, mammalian skin is rich in sweat glands, and many species have scent glands.

All mammals are characterized by the presence of mammary glands, which are modified sweat glands. The ducts of the mammary glands open in certain areas of the skin of the abdominal side. With the exception of monotremes, all mammalian mammary glands are equipped with nipples. Their number varies from 1 to 14 pairs. The mammary glands secrete milk, which is fed to newborns (hence the name of the class).

Of the horny formations of the skin (hair, nails, claws, hooves), hair is the most typical of mammals. In most animals, the hairline is developed on the entire surface of the body (absent on the lips, in some - on the soles). Mammalian hair is heterogeneous. Large, long, stiff, protruding hairs are called vibrissae, they are located at the end of the muzzle, belly, limbs, serve as organs of touch, their bases are connected with nerve endings.

The hair consists of a trunk and a root. The trunk is built of a heart-shaped substance, covered with a cortical layer and outside with a skin. There is air in the cavity of the hair. The hair root ends with a bulb, at the base of which the hair papilla enters. It is rich in blood vessels and serves to nourish the hair. The hair papilla is located in the hair bag, into which the ducts of the sebaceous glands open, secreting a fatty substance that lubricates the hair. The skin of mammals is rich in sebaceous and sweat glands. The latter secrete sweat, due to which thermoregulation is carried out. In moderate and northern latitudes most species change their hair coat twice a year, molting occurs in autumn and spring.

Mammals, like birds, are warm-blooded animals. Their body temperature is constant different types it ranges from 37 to 40 ° C), only in oviparous body temperature depends to a large extent on temperature external environment and fluctuates between 25-36 °C. Perfect thermoregulation of most mammals is ensured by the presence of sweat glands, hairline, fatty subcutaneous tissue, and breathing also takes part in thermoregulation.

Skeleton. The skeleton consists of a skull, spine, limb girdles, and bones of paired limbs. The skull of mammals is characterized by a large volume of the cranial, or brain, box. Its bones grow together at the seams quite late, therefore, during the growth of the animal, the brain can increase in volume. The lower jaw consists of only one (dentary) bone and is attached to the paired temporal bone. The other two bones of the jaw turned into auditory ossicles - the hammer and the anvil. Thus, mammals have three auditory ossicles - the stirrup, hammer and anvil, while amphibians, reptiles and birds have only one - the stirrup (see Table 18).

In the skeleton of mammals, there is a clear division of the spine into five sections: cervical, thoracic, lumbar, sacral and caudal. A constant number of cervical vertebrae (7) is characteristic. On the front side of one of the two cervical vertebrae - the atlas - there are two articular surfaces, like in amphibians. The ribs are attached to the vertebrae of the thoracic region, with their cartilaginous part they are connected to the sternum, or sternum, forming chest. The sacral vertebrae fuse together and are connected to the bones of the pelvic girdle. The number of tail vertebrae ranges from 3 (in the gibbon) to 49 (in the long-tailed pangolin). The degree of mobility of individual vertebrae is different. The most mobile vertebrae are in small running and climbing animals, so their body can bend in different directions, curl up into a ball, etc. The mobility of the vertebrae is due to the articulation of their flat surfaces with cartilaginous discs (menisci) located between the vertebrae.

The forelimb belt consists of paired shoulder blades and clavicles (the latter are not developed in many species). The composition of the forelimb includes the shoulder, two bones of the forearm (ulna and radius) and a hand with phalanges of the fingers.

The hind limb girdle consists of three paired large bones, which in most mammals fuse with the sacral vertebrae. The composition of the hind limb includes the femur, two bones of the lower leg (large and small) and the foot with the phalanges of the fingers. As a result of adaptation to different type movement, the skeleton of the limbs in different mammals has changed greatly. At bats very long phalanges of the fingers support a stretched membrane-wing plane, one-toed horse legs are adapted for fast running, cetacean flippers for swimming, hind legs of kangaroos and jerboas for jumping, etc.

Muscular system. In mammals, it is exceptionally developed, complex and has several hundred individual specialized muscles. Chewing and mimic muscles, especially in monkeys and humans, as well as subcutaneous muscles, reach high development. A typical muscular formation of mammals is the abdominal obstruction, or diaphragm (the muscular septum separating the chest cavity from the abdominal cavity). The diaphragm plays a big role in breathing. When lowering and raising the diaphragm, the volume of the chest changes and intensive ventilation of the lungs is carried out.

Digestive system. The digestive organs begin with a preoral cavity located between the fleshy lips (they are developed only in mammals) and the jaws. On the top and mandibles there are teeth differentiated into certain groups depending on the type of nutrition. There are incisors, canines and molars. These groups of teeth perform various functions: biting off and grinding food, capturing and killing prey, etc. The structure of the teeth is associated with the lifestyle of the animal. The tooth consists of 1-2 roots and a crown. Teeth are built from dentine, cementum and enamel, located in the sockets of the jaw bones. The echidna, anteater and some cetaceans have no teeth. During the development of the animal, two changes of teeth occur - milk and permanent.

At the bottom of the mouth is the tongue, it is involved in chewing and swallowing food. The surface of the tongue is covered with numerous taste buds. The ducts of three pairs of large salivary glands open into the oral cavity. Saliva not only moisturizes food - it contains enzymes that break down starch into glucose during chewing. Thus, food processing begins already in the oral cavity.

Further, food enters the pharynx, esophagus, and from it into the stomach. The structure of the stomach, consisting of cardiac and pyloric sections, is diverse, which is associated with the nature of food. There are many glands in the walls of the stomach. The gastric juice secreted by the glands contains hydrochloric acid and enzymes (pepsin, lipase, etc.). In the stomach, the process of digestion continues. The stomach of ruminant ungulates, which eat a large amount of hard-to-digest coarse plant food, has a particularly complex structure. Digestion of food continues in the duodenum, where the ducts of the liver and pancreas flow. In the small intestines, the breakdown of proteins, fats and carbohydrates is completed and the absorption of essential nutrients occurs. On the border between the small and large intestines in some mammals is the caecum and appendix. Undigested food remains enter the large intestine and are expelled through the rectum.

Respiratory system. The respiratory organs in all mammals begin with the nasal cavity, which has respiratory and olfactory sections. When breathing, air from the nasal cavity enters the larynx, which is supported by several laryngeal cartilages formed by the second and third gill arches. The vocal cords are stretched between the thyroid and arytenoid cartilages. From the larynx, air enters the trachea, which divides into two bronchi. Each of the bronchi enters one of the lungs, branches there, forming a dense network. The smallest pulmonary passages - bronchioles - open into dilated pulmonary vesicles, or alveoli. In the walls of the alveoli, the thinnest blood vessels branch - capillaries, in which gas exchange occurs. The lungs have a complex cellular structure, their respiratory surface is 50-100 times the surface of the body. Contractions of the diaphragm and intercostal muscles increase the volume of the chest cavity, air is pumped into the lungs, and inhalation occurs. When the muscles relax, the volume of the chest cavity decreases, exhalation occurs.

excretory system. The excretory organs are characterized by bladder does not open into the cloaca, but into the urethra. Paired ureters open into the bladder, originating from paired bean-shaped secondary kidneys located in the lumbar region under the spine.

Circulatory system mammals is close to the circulatory system of birds: the heart is four-chambered, the large and small circles of blood circulation are completely separated, but there is not a right, but a left aortic arch (in birds, a right aortic arch). Red blood cells in the formed state are devoid of nuclei.

Nervous system and sense organs. The nervous system has the same sections as in other vertebrates (anterior, interstitial, midbrain, cerebellum and medulla oblongata), but its level of development is much higher. The forebrain, which covers the midbrain and cerebellum, reaches the greatest size and complexity. The surface of the cerebral cortex increases due to convolutions and furrows, the number of which is especially large in higher mammals. In the cerebral cortex there are centers of higher nervous activity that coordinate the work of other parts of the brain and determine the complex behavior of mammals. The cerebellum also progresses strongly, with which the maintenance of muscle tone, balance and proportionality of movements is associated.

The level of development of the sense organs depends on the way of life of animals and obtaining food. For the inhabitants of open spaces, vision is of paramount importance, for nocturnal and twilight animals, inhabitants of forests and thickets of shrubs, reservoirs and burrows, smell and hearing.

The sense of smell in mammals is more developed than in other groups of terrestrial vertebrates. In the upper posterior part of the nasal cavity, a complex system of olfactory turbinates is developed, their surface is covered with a mucous membrane of the olfactory epithelium. The complexity of the structure of the olfactory shells corresponds to the sharpness of the sense of smell. Taste organs are taste buds in the mucous membrane of the mouth and tongue.

The organs of hearing are well developed in the vast majority of mammals. The organ of hearing consists of three sections: the outer, middle and inner ear. The outer ear (pinna) and the external auditory meatus are a kind of filter antenna that amplifies sounds important to the animal and attenuates constant noise. In aquatic mammals and soil inhabitants, the auricle is reduced. The middle ear contains three auditory ossicles, which ensure the perfect transmission of sound waves to the inner ear. The inner ear consists of the auditory and vestibular sections.

In the auditory region, a spirally twisted cochlea is very developed with several thousand of the finest fibers that resonate when sound is perceived. The vestibular region includes three semicircular canals and an oval sac, it serves as an organ of balance and perception of the spatial position of the body. The hearing range of mammals is much wider than that of birds and reptiles, the cochlea allows mammals to distinguish the highest frequencies.

The eye of mammals is covered with a fibrous tissue - the sclera, which in front passes into a transparent cornea. Under the sclera there is a choroid with blood vessels supplying the eye, in front it thickens and forms the iris. The iris is located directly in front of the lens, plays the role of a diaphragm, regulates the illumination of the retina by changing the size of the pupil. The lens has a lenticular shape, it is enlarged in nocturnal and crepuscular animals. Accommodation is achieved only as a result of a change in the shape of the lens. TO inside the choroid is adjacent to the retina - a light-sensitive layer consisting of receptors (rods and cones) and several types of neurons. Many mammals have the ability to distinguish colors; color vision is well developed in humans and higher primates. Horses, for example, distinguish four colors. Vision is well developed in nocturnal animals, in particular, cats distinguish six primary colors and 25 shades. gray color. In animals that lead an underground lifestyle, vision is reduced (some moles, mole rats, etc.).

reproduction. The reproductive organs in the male are represented by paired testes, in the female - by paired ovaries. Fertilization is internal. The fertilized egg begins to divide and descends through the oviduct into the uterus, where the intrauterine development of the embryo occurs. In most mammals, during the development of the embryo, the placenta is formed in the uterus, gas exchange occurs through it, the embryo is nourished and the metabolic products are excreted. In oviparous mammals, the placenta is absent, in marsupials it is rudimentary. The vast majority of mammals are characterized by live birth, and only oviparous ones lay large, yolk-rich eggs. All mammals feed their young with milk. They differ a high degree care for offspring. Most mammals build special nests, even after milk feeding is completed, they take care of their young for a long time and diligently, train them.

Systematics. According to the characteristics of reproduction and organization, modern mammals are divided into three subclasses: cloacal (Monotremata), marsupials (Marsupialia) and placental (Placentalia) (Table 20).

Monotremes, or cloacals (platypus, echidna, prochidna), live only in Australia. They lay rather large eggs with a lot of nutrients. After fertilization, the egg stays in the mother's genital tract for a long time (16-27 days), at which time the embryo develops in it. The period of incubation or carrying the egg is short and does not exceed 10 days. Monotremes lack teeth. The intestines and urogenital organs open into the cloaca. There are no nipples. The shoulder girdle is similar to that of reptiles. Body temperature ranges from 24 to 34 °C. Paired oviducts (fallopian tubes) and the uterus pass into the urogenital sinus. The listed features indicate a significant primitiveness of the structure of cesspools and their proximity to ancestors common with reptiles.

Lower animals, or marsupials (kangaroo, marsupial wolf, marsupial mole, etc.), live in Australia and South America. They do not have a placenta (except for some species), the cubs are born underdeveloped and are born in a bag, hanging on the nipple (for example, a giant kangaroo weighing 60-70 kg gives birth to a cub weighing only 80 g the size of Walnut, other marsupials have even smaller newborns). Newborn marsupials independently crawl into the mother's pouch, where they find the nipple. As soon as the cub finds the nipple, the latter swells and fills the oral cavity of the newborn. The calf feeds on milk and lives in the mother's pouch from 60 days in small species to 250 days in large species. The brain of marsupials is primitive. There are two uteruses and two vaginas. Teeth, except for the front molar, are not replaced. Body temperature is not strictly constant, but higher than that of single passers.

The vast majority of modern mammals belong to the higher animals, or placentals. Their features are that the nutrition of the embryo occurs through the placenta. The cub is born more or less developed and can suck milk. The brain is well developed. There are two changes of teeth.

Modern placental are divided into 16 orders. The most important of them are: insectivores, bats, edentulous, rodents, carnivores, pinnipeds, cetaceans, ungulates, proboscis, primates. The order of insectivores, very ancient in origin, is distinguished by the greatest primitiveness of the structure. One of the most highly organized orders (although retaining many primitive structural features) are primates. Characteristic features of the main orders of mammals are given in table. 21.

Allocate suborders lower primates, or semi-monkeys (tupai, lemurs, tarsiers), and higher primates. Among the latter, a group of broad-nosed (marmosets, howler monkeys, arachnids and woolly monkeys), narrow-nosed (monkeys, macaques and baboons) and anthropoid (orangutans, chimpanzees, gorillas) monkeys are distinguished. All groups of modern primates are characterized by a high level of specialization.

Apes are the most highly developed animals. They differ in the complex structure of the cerebral cortex, do not have cheek pouches, tail and ischial calluses. The appendix of the caecum is long (20-25 cm). They have four blood types, just like humans.

TO higher primates the family of people with the only modern species Homo sapiens also applies ( Homo sapiens). According to archaeologists, the region of human origin, apparently, was Africa. Morphologically, a person is characterized by an exceptional development of the brain, a weak development of the jaws and teeth, a strongly developed tongue and a chin protrusion. hairline reduced, the spine is straightened, the skull is on the spinal column from above, the legs end in an arched foot, the hand is a very perfect and versatile organ. Man owns articulate speech and is capable of very complex mental activity. The formation of Homo sapiens was associated with labor activity.

Economic and medical importance of mammals

It is difficult to name any group of animals that would have such significance in the history of mankind and in the economy of the national economy as mammals. They were first domesticated by primitive man (he received from them food, raw materials for the production of clothing, shoes and draft power). Over time, hundreds of breeds of large and small cattle, pigs, horses, which are of great economic importance.

Currently, there are various breeds of cows (dairy - Kholmogory, Dutch, Yaroslavl; meat and dairy - Kostroma, Simmental; meat - Kalmyk, Shorthorn) and sheep (Romanov, Karakul, Askani and Caucasian fine-fleeced). One of the most important branches of agriculture is pig breeding. Especially valuable breed- steppe Ukrainian white pig, bred by the Soviet livestock breeder M.F. Ivanov. There are many breeds of domestic horses, in particular, Oryol trotters, Don, Arabian, English, Vladimir, etc.

Camels, buffaloes, yaks, donkeys, and deer are also used in the national economy. In the northern regions of Russia, reindeer husbandry is an important branch of the economy; reindeer. Red deer are bred in park and hunting farms to obtain antlers - non-ossified horns containing pantocrine and other medicinal substances. For the same purpose, Far Eastern spotted deer, deer. Deer and other wild ungulates are also a source of meat and skins.

Whales are important fish species. They produce margarine, lubricants, glycerin, gelatin, glue, soap, cosmetics and drugs (in particular, vitamin A from the liver). From meat, viscera and bones are made fodder meal for pets, as well as fertilizers. A valuable product is sperm whale spermaceti. Marine whaling is regulated by international agreements, but the number of whales and sperm whales is noticeably declining. Currently hunting for gray and blue whales, humpback whales and fin whales is prohibited international convention. There is limited hunting for sperm whales, sei whales, bottlenose whales, pilot whales. valuable objects sea ​​fur hunting are pinnipeds. Skins, seals, harp and Caspian seals are used as fur raw materials (young animals), as well as for the needs of the leather industry. Fur is especially prized fur seals, which form large rookeries in Russia on the Komandorskie and Tyuleniy Islands, in the USA - on the Pribylov Islands. Fat and meat of pinnipeds are also used.

The USSR ranks first in the world in the production of fur-bearing animals. The bulk of the fishery is made up of 20 species. The main commercial species of the forest zone are sable, squirrel, marten, ermine, foxes and hares, and the tundra - arctic fox and white hare, in the steppes and deserts - foxes, hares, ground squirrels, in river valleys - muskrat, water rat, otter, coypu (on South). About a third of furs are mined in the north of our country. Hunting for valuable fur animals is carefully regulated and carried out on a scientific basis, which also provides for the protection and breeding of animals. Particularly great successes have been achieved in increasing the number of sables and in the artificial resettlement of the beaver. The artificial resettlement of the sable to the forests of the Tien Shan, the Far Eastern raccoon dog and spotted deer to the European part of Russia has also been carried out. Some fur-bearing animals have been successfully acclimatized in our country, in particular, the North American muskrat, the South American nutria, and the American mink.

Some species of mammals (rats, mice, guinea pigs, etc.) are used as laboratory animals in biological and medical research and are bred in large numbers.

Many wild mammals are reservoirs for a number of vector-borne diseases. Ground squirrels, marmots, tarbagans and other rodents are a source of human infection with plague and tularemia, mouse-like rodents and rats with toxoplasmosis, epidemic typhus, plague, tularemia, trichinosis and other diseases.

Mammals also have great importance as consumers of harmful insects (for example, insectivores - shrews, moles, hedgehogs; bats - ears, red evening, etc.); some representatives of the predatory order - weasel, ermine, black polecat, pine marten, badger and others - feed on harmful rodents and insects. During the day, weasel gets 5-6 rodents, mainly red, gray and water voles, in summer it also feeds on click beetles. The badger feeds on mouse-like rodents and larvae of beetles, click beetles, weevils, and leaf beetles.

Some mammals bring great losses to the national economy. Many species of rodents (mice, voles, ground squirrels, rats) damage agricultural and forest crops, pastures, stocks in storages. Their harmfulness is increased by the fact that voles and mice are capable of mass reproduction. Marmots, ground squirrels, gerbils, some voles, mice and other rodents can store and spread pathogens of dangerous diseases in humans and domestic animals (plague, tularemia, foot-and-mouth disease, etc.), carriers of serious diseases feed on their blood - ticks, fleas, lice, mosquitoes, Some predatory mammals And the bats store and transmit rabies pathogens. Many of these infections constantly exist in nature, that is, they have a natural focality. People and pets can get sick if they enter the territory of a natural focus and come into contact with sick animals or vectors. The theory of natural focality of diseases was developed by an outstanding Soviet zoologist acad. E. N. Pavlovsky and his students. This theory has become scientific basis organizations to fight these diseases.

Pests in agriculture and forestry are most often exterminated with the help of pesticides, but their use has negative consequences - environmental poisoning, the death of many useful animals, etc. Currently, in Russia, a bacterial preparation bactorodencid is produced in a semi-industrial way to control rodents. The drug is added to baits made from grain, chopped potatoes, bread crumbs.

Ferrets, foxes, jackals can cause some harm to poultry farming, however, in natural conditions they more often feed on mouse-like rodents, and some also on carrion, etc. Many valuable wild and domestic animals are destroyed by wolves, in a number of places it is necessary to limit their numbers, like the number of some other predators, by shooting.

Fur farming

Fur farming in our country arose about 200 years ago, in the USSR this branch of animal husbandry began to develop intensively from 1928-1929, when the first specialized fur farms for the production of furs for export were created. Currently, fur farming is developing in three main areas: free, or island (this is how ungulates are bred mainly - deer, spotted deer, elk, which give antlers, skin and meat), semi-free (the main herd is kept in cages, young animals - in a limited area ) and cellular. The latter direction is the main form of modern industrial fur farming. Large fur farms contain up to 100 thousand animals, with 85-90% total The main herd of females is mink of various colors. They also grow nutria, foxes, arctic foxes, sables, chinchillas, river beavers. As a result of the successful use of genetic breeding techniques, more than 30 types of colored minks, several types of colored foxes and blue foxes have been bred. In total, about 20 species of animals are bred in the world.

Mammal Conservation

Over the past century on the globe More than 100 species of mammals have been completely destroyed; currently, about 120 species of mammals are under the threat of extinction. The problem of maintaining and increasing the number of polar bear, tiger, snow leopard, bison, wild spotted deer, some species of whales and seals and other animals. For this purpose, back in the USSR, the Law "On the Protection and Use of the Wildlife" was adopted, in accordance with it, rare and endangered species of animals are entered in the Red Book of the USSR and the Red Books of the Union Republics. Shooting and trapping of rare and endangered species of animals is prohibited in our country, nature reserves, sanctuaries, and micro-reserves have been created where integral natural communities of animals are preserved.

Many mammals are partly aquatic, living near lakes, streams, or coastlines oceans (for example, seals, sea ​​lions, walruses, otters, muskrats and many others). Whales and dolphins () are completely aquatic and can be found in all and some rivers. Whales can be found in polar, temperate and tropical waters, both near the coast and in the open ocean, and from the surface of the water to a depth of more than 1 kilometer.

The habitat of mammals is also characterized by various climatic conditions. For example, the polar bear lives calmly at sub-zero temperatures, while lions and giraffes need a warm climate.

Mammal groups

Baby kangaroo in mother's pouch

There are three main groups of mammals, each of which is characterized by one of the main features of embryonic development.

• Monotremes or oviparous (Monotremata) lay eggs, which is the most primitive reproductive feature in mammals.
• marsupials (Metatheria) are characterized by the birth of underdeveloped young after a very short gestation period (8 to 43 days). Offspring are born at a relatively early stage of morphological development. The cubs are attached to the mother's nipple and sit in the bag, where their subsequent development takes place.
• Placental (Placentalia) are characterized by long gestation (pregnancy), during which the embryo interacts with its mother through a complex embryonic organ - the placenta. After birth, all mammals depend on the milk of their mothers.

Lifespan

Just as mammals vary greatly in size, so does their lifespan. Usually, small mammals live less than the larger ones. Bats ( Chiroptera) are an exception to this rule - these relatively small animals can live for one or more decades in natural conditions, which is much longer than the lifespan of some more large mammals. Life expectancy ranges from 1 year or less to 70 years or more in the wild. Bowhead whales can live for over 200 years.

Behavior

The behavior of mammals varies significantly among species. Since mammals are warm-blooded animals, they require more energy than cold-blooded animals of the same size. Activity indicators of mammals reflect their high energy requirements. For example, thermoregulation plays an important role in the behavior of mammals. Those animals that live in colder climates need to keep their bodies warm, while mammals that live in hot and dry climates need to cool down to keep their bodies hydrated. Behavior is an important way for mammals to maintain physiological balance.

There are species of mammals that exhibit almost every type of lifestyle, including vegetative, aquatic, terrestrial, and arboreal. Their ways of moving around their habitat are varied: mammals can swim, run, fly, glide, and so on.

Social behavior also varies considerably. Some species can live in groups of 10, 100, 1000 or more individuals. Other mammals are generally solitary except when mating or rearing offspring.

The nature of activity among mammals also covers the full range of possibilities. Mammals can be nocturnal, diurnal, or crepuscular.

Nutrition

Most mammals have teeth, although some animals, such as baleen whales, have lost them during evolution. Because mammals are widely distributed in a variety of habitats, they have a wide range of feeding habits and preferences.

Marine mammals feed on a variety of prey including small fish, crustaceans and sometimes other marine mammals.

Among land mammals there are herbivores, omnivores and carnivores. Each individual takes its place in.

Being warm-blooded, mammals require much more food than cold-blooded animals of the same size. Thus, a relatively small number of mammals may have big influence on the population of their food preferences.

reproduction

Mammals tend to reproduce sexually and have internal fertilization. Almost all mammals are placental (with the exception of oviparous and marsupials), that is, they give birth to live and developed young.

Generally, most mammalian species are either polygynous (one male mates with several females) or promiscuous (both males and females have multiple matings in this season reproduction). Since females carry and nurse their offspring, it often happens that male mammals can produce many more offspring during the mating season than females. As a consequence, the most common mating system in mammals is polygyny, with relatively few males fertilizing many females. At the same time, a large number of males do not participate in reproduction at all. This scenario sets the stage for intense competition between males among many species, and also allows females to choose a stronger mating partner.

Many mammalian species are characterized by sexual dimorphism, whereby males are better able to compete for access to females. Only about 3% of mammals are monogamous and only mate with the same female each season. In these cases, males may even participate in the upbringing of offspring.

As a rule, the reproduction of mammals depends on their habitat. For example, when resources are scarce, males spend their energy breeding with a single female and provide food and protection for the young. If, however, resources are plentiful and the female can ensure the well-being of her offspring, the male goes to other females. In some mammals, polyandry is also common, when a female has bonds with several males.

In most mammals, the embryo develops in the uterus of the female until it is fully formed. The born cub is fed with mother's milk. In marsupials, the embryo is born underdeveloped, and its further development takes place in the mother's pouch, as well as feeding with mother's milk. When the calf reaches full development, it leaves the mother's pouch, but can still spend the night in it.

Five species of mammals that belong to the order Monotremes actually lay eggs. Like birds, representatives of this group have a cloaca, which is a single opening that serves for emptying and reproduction. The eggs develop inside the female and receive the necessary nutrients for several weeks before laying. Like other mammals, monotremes have mammary glands and females feed their offspring with milk.

Offspring need to grow, develop and maintain optimal temperature body, but feeding the young with nutrient-rich milk takes a lot of energy from the female. In addition to producing nutritious milk, the female is forced to protect her offspring from all sorts of threats.

In some species, the cubs stay with their mother for a long time and learn the necessary skills. Other species of mammals (such as artiodactyls) are already born quite independent and do not need excessive care.

Role in the ecosystem

The ecological roles or niches filled by more than 5,000 mammal species are varied. Each mammal takes its place in the food chain: there are omnivores, carnivores and their victims - herbivorous mammals. Each species, in turn, affects. Due in part to their high metabolic rates, the impact that mammals have on nature is often disproportionate to their abundance. Thus, many mammals may be carnivores or herbivores in their communities, or play an important role in seed dispersal or pollination. Their role in the ecosystem is so diverse that it is difficult to generalize. Despite their low species diversity, compared with other groups of animals, mammals have a significant impact on the global.

Significance for a person: positive

Mammals are important to mankind. Many mammals have been domesticated to provide humankind with foods such as meat and milk (such as cows and goats) or wool (sheep and alpacas). Some animals are kept as service or pets (eg dogs, cats, ferrets). Mammals are also important to the ecotourism industry. Think of the many people who go to zoos or all over the world to see animals such as whales or whales. Mammals (eg bats) often control pest populations. Some animals, such as rats and mice, are vital to medical and other scientific research, while other mammals can serve as models in human medicine and research.

Significance for a person: negative

plague epidemic

Some species of mammals are believed to have a detrimental effect on human interests. Many species that eat fruits, seeds, and other types of vegetation are crop pests. Carnivores are often considered a threat to livestock or even for people's lives. Mammals common in urban or suburban areas can become a problem if they cause damage to cars when they get on the road or become household pests.

Several species coexist well with humans, including domesticated mammals (eg, rats, house mice, pigs, cats, and dogs). However, as a result of the intentional or unintentional introduction of invasive (non-native) species into ecosystems, they have adversely affected the local biodiversity of many regions of the world, especially the endemic island biota.

Many mammals can transmit diseases to humans or livestock. Bubonic plague considered the most famous example. This disease is spread by fleas carried by rodents. Rabies is also a significant threat to livestock and can also kill people.

Security

Overexploitation, habitat destruction and fragmentation, introduction invasive species and other anthropogenic factors threaten the mammals of our planet. Over the past 500 years, at least 82 species of mammals are considered extinct. About 25% (1,000) of mammal species are currently listed on the IUCN Red List, as they are at various risks of extinction.

Species that are rare or require large ranges are often at risk due to habitat loss and fragmentation. Animals known to threaten people, livestock or crops may die at the hands of humans. Those species that are exploited by humans for quality (for example, for meat or fur), but not domesticated, are often depleted to critically low levels.

Finally, it negatively affects flora and fauna. The geographic ranges of many mammals change due to changes in temperature. As temperatures rise, which is especially noticeable in the polar regions, some animals are unable to adapt to new conditions, and therefore may disappear.

Protective measures include tracking habitats and carrying out a set of measures to protect mammals.

Mammals are warm-blooded vertebrates. Their heart is four-chambered. Skin with many glands. Developed hairline. Cubs are fed with milk, which is produced in the mammary glands of the female. The central nervous system is highly developed. Mammals inhabit land, seas and fresh water. All of them descended from terrestrial ancestors. More than 4000 species are known.

Most mammals are quadrupeds. The body of these animals is raised high above the ground. The limbs have the same sections as the limbs of amphibians and reptiles, but are located not on the sides of the body, but under it. Such structural features contribute to a more perfect movement on land. Mammals have a well-defined neck. The tail is usually small and. sharply separated from the body. The body is covered with hair. Hair on the body is not uniform. Distinguish between undercoat (protects the body from cooling) and awn (does not allow the undercoat to fall off, protects it from pollution). The molt inherent in mammals is expressed in the loss of old hair and its replacement with new ones. Most animals have two molts during the year - in spring and autumn. Hair is made up of horny matter. Horny formations are nails, claws, hooves. The skin of mammals is elastic and contains sebaceous, sweat, milk and other glands. The secretions of the sebaceous glands lubricate the skin and hair, making them elastic and non-wettable. Sweat glands secrete sweat, the evaporation of which from the surface of the body protects the body from overheating. The mammary glands are present only in females and function during the period of feeding the cubs.

Most mammals have five-fingered limbs. However, in connection with the adaptation to movement in different environment there are changes in their structure. For example, in whales and dolphins, the forelimbs have changed into flippers, in bats - into wings, and in moles they look like spatulas.

The mouth of mammals is surrounded by fleshy lips. The teeth located in the mouth serve not only to hold prey, but also to grind food, and therefore they are differentiated into incisors, canines and molars. The teeth have roots which they are fixed in the sockets of the jaws. Above the mouth is a nose with a pair of external nasal openings - nostrils. The eyes have well developed eyelids. The nictitating membrane (third eyelid) is underdeveloped in mammals. Of all animals, only mammals have an outer ear - the auricle.

The skeleton of mammals is similar to that of reptiles and consists of the same sections. However, there are also some differences. For example, the skull in mammals is larger than in reptiles, which is associated with large sizes brain. Mammals are characterized by the presence of seven cervical vertebrae (38). The thoracic vertebrae (usually 12-15) together with the ribs and sternum form a strong chest. Massive lumbar vertebrae are movably articulated with each other. The number of lumbar vertebrae can be from 2 to 9. The sacral region (3-4 vertebrae) fuses with the bones of the pelvis. The number of vertebrae of the caudal region varies considerably and can be from 3 to 49. The belt of the forelimbs of mammals consists of two shoulder blades with crow bones attached to them and two clavicles. The belt of the hind limbs - the pelvis - is formed by three pairs of usually fused pelvic bones. The skeletons of the limbs of mammals are similar to those of reptiles. Most mammals have well developed muscles of the back, limbs and their belts.

Digestive system.

Almost all mammals bite off food with their teeth and chew it. At the same time, the food mass is abundantly moistened with saliva secreted into the oral cavity. salivary glands. Here, along with grinding, digestion of food begins. The stomach in most mammals is single-chambered. In its walls are glands that secrete gastric juice. The intestine is divided into small, large and rectum. In the intestines of mammals, as well as in reptiles, the food mass is exposed to the action of digestive juices secreted by the intestinal glands, liver and pancreas. The remains of undigested food are removed from the rectum through the anus.

In all animals, the chest cavity is separated from the abdominal cavity by a muscular septum - the diaphragm. It protrudes into the chest cavity with a wide dome and is adjacent to the lungs.

Breath.

Mammals breathe atmospheric air. respiratory system make up the nasal cavity, larynx, trachea, lungs, characterized by a large branching of the bronchi, which end in numerous alveoli (pulmonary vesicles), braided with a network of capillaries. Inhalation and exhalation are carried out by contraction and relaxation of the intercostal muscles and the diaphragm.

Circulatory system. Like birds, the mammalian heart consists of four chambers: two atria and two ventricles. Arterial blood does not mix with venous blood. Blood flows through the body in two circles of blood circulation. The mammalian heart provides intensive blood flow and supply of body tissues with oxygen and nutrients, as well as the release of tissue cells from decay products.

The excretory organs of mammals are the kidneys and skin. A pair of bean-shaped kidneys is located in the abdominal cavity on the sides of the lumbar vertebrae. The resulting urine through two ureters enters the bladder, and from there through the urethra is periodically removed to the outside. Sweat released from the sweat glands of the skin also removes a small amount of salt from the body.

Metabolism. A more perfect structure of the digestive organs, lungs, heart and others provides in animals high level metabolism. Due to this, the body temperature of mammals is constant and high (37-38°C).

The nervous system has a structure characteristic of all vertebrates. Mammals have a well-developed cerebral cortex. Its surface is significantly increased due to the formation a large number folds - convolutions. In addition to the forebrain, the cerebellum is well developed in mammals.

Sense organs. Mammals have well-developed sense organs: olfactory, auditory, visual, tactile and gustatory. The organs of vision are better developed in animals living in open areas. Animals living in the forest have better developed organs of smell and hearing. The organs of touch - tactile hairs - are located on the upper lip, cheeks, above the eyes.

Reproduction and development of mammals. Mammals are dioecious animals. In the reproductive organs of the female - the ovaries - eggs develop, in the reproductive organs of the male - testicles - spermatozoa. Fertilization in mammals is internal. Mature cells enter the paired oviduct, where they are fertilized. Both oviducts open into a special organ of the female reproductive system - the uterus, which only mammals have. The uterus is a muscular bag, the walls of which are capable of greatly stretching. The ovum that has begun to divide is attached to the wall of the uterus, and all further development of the fetus occurs in this organ. In the uterus, the shell of the embryo is in close contact with its wall. At the point of contact, a child's place, or placenta, is formed. The embryo is connected to placenta umbilical cord, within which its blood vessels pass. In the placenta, through the walls of blood vessels from the mother's blood, nutrients and oxygen enter the blood of the fetus and carbon dioxide and other waste products harmful to the fetus are removed. The duration of the development of the embryo in the uterus in different mammals is different (from several days to 1.5 years). At a certain stage, the embryo of mammals has the rudiments of gills and, in many other ways, is similar to the embryos of amphibians and reptiles.

Mammals have a well-developed instinct for caring for offspring. Female mothers feed their cubs with milk, warm them with their bodies, protect them from enemies, and teach them to look for food. Care for offspring is especially strongly developed in mammals, whose cubs are born helpless (for example, a dog, a cat).

Origin of mammals.

The similarity of modern mammals with reptiles, especially on early stages embryonic development, indicates the close relationship of these groups of animals and suggests that mammals are descended from ancient reptiles (39). In addition, even now in Australia and on the islands adjacent to it live oviparous mammals, which, in their structure and characteristics of reproduction, occupy an intermediate position between reptiles and mammals. These include representatives detachment of oviparous, or pervozveri - platypus and echidna.

When breeding, they lay eggs covered with a strong shell that protects the contents of the egg from drying out. The female platypus lays 1-2 eggs in a burrow, which she then incubates. Echidna bears a single egg in a special bag, representing a fold of skin on the ventral side of the body. The hatchlings that hatch from the egg are fed with milk.

Order Marsupials. These include kangaroo, marsupial wolf, marsupial bear koala, marsupial anteaters. In marsupials, unlike the first animals, the development of the embryo occurs in the mother's body, in the uterus. But there is no placenta, or placenta, and therefore the cub does not stay in the mother's body for long (for example, in a kangaroo). The cub is born underdeveloped. Further development it occurs in a special fold of skin on the mother's abdomen - a bag. First animals and marsupials are an ancient group of mammals, widespread in the past.

The importance of mammals and the protection of useful animals.

The importance of mammals for humans is very diverse. Certainly harmful are many rodents that damage crops and destroy food supplies. These animals are also distributors of dangerous human diseases. A certain harm to the human economy is caused by some predatory mammals (in our country - the wolf), attacking livestock.

The benefits of wild mammals are in obtaining valuable meat, skin and fur from them, and also fat from sea animals. In the USSR, the main game animals are squirrel, sable, muskrat, fox, arctic fox, and mole.

In order to enrich the fauna (fauna is called species composition animal world of any country or region) in our country are constantly taking measures for acclimatization (introduction from other regions or countries) and resettlement of useful animals.

In the USSR, under the protection of the law are many species of mammals, the hunting of which is completely prohibited.

The main orders of placental mammals: