Class Mammals, or animals. digestive system. breath. origin of mammals. the importance of mammals and the protection of useful animals. What animals are mammals. Presentation on the theme of mammals in elementary school Mammal group

Mammals, considered the most developed animals (including humans as a species), are so named because they have mammary glands that allow females to feed their cubs with their own milk.

Mammals have larger and more developed brains than other animals. Some of them are endowed with amazing abilities and a kind of intelligence, such as primates (chimpanzees) and cetaceans (dolphin). In most mammals, the body is covered with hair. With the exception of man, who walks on two legs, mammals usually move with the help of four limbs, which in different zoological species have different shape(hand, hoof, webbed foot, fin), but always with fingers (from one to five). And finally, almost everyone has teeth.

The class of currently existing mammals includes about 4200 species, extremely diverse in appearance and your behavior. Some animals are very tiny, others are real giants. Some are thriving and ubiquitous, while others are endangered. And although most of them, so to speak, are terrestrial creatures, there are also amphibians (beavers, otters, platypuses), and inhabitants of the sea (whales, dolphins), and some even know how to fly through the air, like birds (bats).

Mammals are divided into three large groups depending on how they produce offspring: cloacal (first animals), marsupials and placental. It is to the latter that man belongs. The most amazing animals are cloacal, or monotremes: they reproduce by laying large eggs, which then incubate (oviparous reproduction). Egg-laying animals are very few in number. They are represented by only two families living in Australia, Tasmania and New Guinea: echidna and platypus.

In marsupials, the young are born underdeveloped and complete their development in the mother's brood abdominal pouch. They are divided into two groups: one lives in Australia 1 kangaroo), and the other - in South America(opossum). As for placental mammals, whose cubs are born fully developed, they are the most. There are several orders: carnivores, insectivores, rodents, ungulates, edentulous, cetaceans, primates.

interesting similarity

Mammals living on different continents are sometimes strikingly similar. Large South American rodents (capybara, agouti, mara, paca) resemble the pygmy hippopotamus or water deer - the inhabitants of Africa. The American feline, the jaguarundi, is very similar to the giant civet cat from Madagascar. It's about about the so-called phenomenon of convergence: animals belonging to different groups, but living in similar conditions, acquire a certain similarity.

Pangolin - dl. from 80 cm to 1.5 m

Flying monkey - dl. 40 cm

Seal - dl. from 1.5 to 4 m

Platypus - dl. 40 cm, tail - 12 cm

Dolphin - dl. from 2 to 4 m

Gorilla - standing height 1.8 m

Elephant - dl. from 2 to 4 m

Lemur - dl. 50cm tail 50cm

Chimpanzee - standing height 1.4 m

Kangaroo - dl. up to 1.5 m, tail up to 1 m

Dwarf bat - dl. 4.5 cm, tail 3 cm, r.k. 20 cm

Bison - dl. 2.6 m, tail 70 cm, c. 1.2 m

Wild boar - dl. from 1.2 to 1.6 m, c. 60 cm to 1 m

Fox - length 70 cm, tail 45 cm

Hedgehog - length. 25 cm

Giraffe - common c. - 5.5 m, tail 80 cm

Camel - common c. 2 m

Leo - dl. 1.7 m, tail 80 cm

Hippo - dl. 4m, tail 40 cm, c. 1.5 m

Many mammals are partly aquatic, living near lakes, streams, or ocean shorelines (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, polar bear lives quietly 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 offspring after a very short period pregnancy (from 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 vivo, which is significantly longer than the lifespan of some larger mammals. Life expectancy ranges from 1 year or less to 70 years or more in the wild. bowhead whales can live 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 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.

Food

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 eat various types mining, 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 a given breeding season). 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, and 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 human life. 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 negatively affected the local biodiversity of many regions of the world, especially the endemic biota of islands.

Many mammals can transmit diseases to humans or livestock. Bubonic plague is 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 others 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. Central nervous system 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- in the 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 the large size of the 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. sacral department(3-4 vertebrae) grows together 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 in 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 buds is located in abdominal cavity on the sides of the lumbar vertebrae. The resulting urine passes through the two ureters to the bladder, and from there urethra periodically released. 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 increases significantly due to the formation of a large number of 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 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 special body 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 fetus is connected to the placenta by the umbilical cord, inside 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 in the early stages of embryonic development, indicates the close relationship of these groups of animals and suggests that mammals are descended from ancient reptiles (39). In addition, egg-laying mammals still live in Australia and on the islands adjacent to it, which, in their structure and reproduction characteristics, occupy an intermediate position between reptiles and mammals. These include representatives detachment of oviparous, or the first animals, the platypus and the 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. They include kangaroos, 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 - ancient group 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 include many rodents that are harmful cultivated plants and destroying 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:

Animals or mammals are the most highly organized. A developed nervous system, breastfeeding of young, live birth, warm-bloodedness allowed them to spread widely throughout the planet and occupy a wide variety of habitats. Mammals are animals that live in forests (wild boars, elks, hares, foxes, wolves), mountains (rams, steppes and semi-deserts (jerboas, hamsters, ground squirrels, saigas), in soil (mole rats and moles), oceans and seas ( dolphins, whales). Some of them (for example, bats) spend a significant part of their active life in the air. Today, the existence of more than 4 thousand species of animals is known. Orders of mammals, as well as characteristics inherent in animals - we will talk about all this in this article. Let's start with a description of their structure.

External structure

The body of these animals is covered with hair (even whales have its remains). There are coarse straight hair (awn) and thin sinuous (undercoat). The undercoat protects the awn from pollution and matting. The coat of mammals can consist only of an awn (for example, in deer) or an undercoat (like in moles). These animals molt periodically. In mammals, this changes the density of the fur, and sometimes the color. In the skin of animals there are hair follicles, sweat and sebaceous glands and their modifications (mammary and odorous glands), horny scales (as on the tail of beavers and rats), as well as other horny formations found on the skin (horns, hooves, nails, claws). Considering the structure of mammals, we note that their legs are located under the body and provide these animals with more perfect movement.

Skeleton

In the skull they have a highly developed brain box. In mammals, teeth are located in the cells of the jaws. Usually they are divided into molars, canines and incisors. The cervical spine in almost all animals consists of seven vertebrae. They are movably connected to each other, except for the sacral and two caudal, which, growing together, form the sacrum - a single bone. The ribs articulate with the thoracic vertebrae, which are usually from 12 to 15. In most mammals, the forelimb belt is formed by paired shoulder blades and clavicles. Only a small part of the animals preserved crow bones. The pelvis consists of two pelvic bones fused with the sacrum. The skeleton of the limbs is from the same bones and sections as those of other representatives of four-legged vertebrates.

What are the sense organs of mammals?

Mammals are animals that have auricles that help detect odors as well as determine their direction. Their eyes have eyelids and eyelashes. Vibrissae are located on the limbs, belly, head - long stiff hair. Animals with their help feel even the slightest touch to objects.

Origin of mammals

Just like birds, mammals are descendants of ancient reptiles. This is evidenced by the similarity of modern animals with modern reptiles. In particular, it manifests itself in the early stages of embryonic development. More large quantity signs of similarity were found in them with the animal-toothed lizards, which became extinct many years ago. Also for kinship with reptiles is the fact that there are animals that lay eggs containing many nutrients. Some of these beasts have cesspools, developed crow bones, and other signs of low organization. We are talking about the first animals (oviparous). Let's talk about them in more detail.

First beasts

This is a subclass of the most primitive mammals alive today. Together with the signs already mentioned, it should be noted that they do not have a constant body temperature. The mammary glands of the first animals do not have nipples. The young hatched from the eggs lick the milk from the mother's fur.

In this subclass, one detachment stands out - Single-pass. It includes 2 species: echidna and platypus. These animals today can be found in Australia, as well as on the islands adjacent to it. The platypus is a medium-sized animal. He prefers to settle along the banks of the rivers and leads here semi-aquatic image life. In a hole dug by him in a steep bank, he spends most time. In the spring, the female platypus lays eggs (there are usually two of them) in a special hole equipped with a nesting chamber. Echidnas are burrowing animals. Their body is covered with hard wool and needles. The females of these animals lay one egg, which they place in a bag - a fold of skin located on the abdomen. The cub hatched from it remains in the bag until needles appear on its body.

marsupials

The Marsupials squad includes animals that give birth to underdeveloped cubs, after which they carry them in a special bag. They have a poorly developed or not formed placenta. Marsupials are distributed mainly in Australia, as well as on the islands adjacent to it. The most famous of them are marsupial and gigantic kangaroo.

Insectivores

Insectivores are a detachment that unites ancient placental primitive animals: hedgehogs, shrews, moles, desmans. Their muzzle is elongated, there is an elongated proboscis. Insectivores have small teeth and five-toed feet. Many of them have odorous glands near the root of the tail or on the sides of the body.

Shrews are the smallest representatives of insectivores. They live in meadows, shrubs, dense forests. These animals are voracious and attack small animals. AT winter time they make passages under the snow and find insects.

Moles are animals that lead an underground lifestyle. They dig numerous holes with their front legs. The eyes of the mole are poorly developed and are black dots. The auricles are in their infancy. The short, dense coat has no definite direction and lies close to the body when moving. Moles are active all year round.

Bats

Detachment The bats or Chiroptera includes animals of medium and small sizes, which are capable of long-term flight. They are especially numerous in the subtropics and tropics. These types of teeth. The most common in our country are earflaps, leather, evening wear. settle in the attics of houses, in hollows of trees, in caves. During the day, they prefer to sleep in their shelters, and at dusk they go out to catch insects.

rodents

This detachment unites a third of the mammalian species that inhabit our planet today. These include squirrels, ground squirrels, rats, mice and other animals of medium and small size. Rodents are mostly herbivores. They have strongly developed incisors (two in each jaw), molars with a flat chewing surface. Rodent incisors have no roots. They are constantly growing, self-sharpening and wear down when eating food. Most rodents have a long intestine with a caecum. rodents lead tree image life (dormouse, flying squirrels, squirrels), as well as semi-aquatic (muskrats, nutria, beavers) and semi-underground (ground squirrels, rats, mice). They are fertile animals. Most of them cubs are born blind and naked. It usually occurs in nests, hollows and burrows.

Lagomorphs

This detachment unites various as well as pikas - animals that are similar in many respects to rodents. chief hallmark lagomorphs is specific dental system. They have 2 small incisors behind the 2 large upper ones. Hares (hare, hare) feed on the bark of shrubs and young trees, grass. They come out to feed at dusk and at night. Their cubs are born sighted, with thick hair. Unlike hares, rabbits dig deep holes. The female, before giving birth to naked and blind cubs, makes a nest from fluff, which she pulls out of her chest, as well as from dry grass.

Predatory

Representatives of this order (bears, ermines, martens, lynxes, arctic foxes, foxes, wolves) usually feed on birds and other animals. Your prey predatory mammal actively pursues. The teeth of these animals are divided into incisors, molars and canines. The most developed are fangs, as well as 4 molars. The members of this group short intestine. This is due to the fact that a predatory mammal eats easily digestible and high-calorie food.

pinnipeds

Let's move on to the consideration of pinnipeds. Their representatives (walruses, seals) are large predatory marine mammals. The body of most of them is covered with sparse coarse hair. The limbs of these animals are modified into flippers. A thick layer of fat is deposited under their skin. The nostrils open only for the time of inhalation and exhalation. When diving, the ear holes are closed.

cetaceans

Real marine mammals - whales and dolphins - are included in this order. Their body is fish-shaped. These marine mammals for the most part do not have hair on their bodies - they are preserved only near the mouth. The forelimbs were transformed into flippers, while the hind limbs are absent. In the movement of cetaceans, a powerful tail, which ends in a caudal fin, is of great importance. It is incorrect to say that marine mammals are fish. These are animals, although outwardly they resemble fish. Representatives of cetaceans are the largest mammals. Blue whale reaches a length of 30 meters.

artiodactyls

This detachment includes medium-sized and large omnivores and herbivores. Their legs have 2 or 4 fingers, most of them are covered with hooves. According to the peculiarities of the structure of the stomach and methods of nutrition, they are divided into non-ruminant and ruminant. The latter (sheep, goats, deer) have incisors only on the lower jaw, and the molars have a wide chewing surface. Non-ruminants have a single-chamber stomach, and the teeth are divided into molars, canines and incisors.

Odd-toed ungulates

We continue to describe the orders of mammals. Odd-toed ungulates are such animals as horses, zebras, donkeys, tapirs, rhinos. On their feet, most of them have a developed toe, on which there are massive hooves. Today, only Przewalski's horse has survived.

Primates

These are the most highly developed mammals. The order includes half-monkeys and monkeys. They have grasping five-fingered limbs, while thumb brushes are opposed to the rest. Almost all primates have a tail. The vast majority of them live in the subtropics and tropics. They inhabit mainly forests, where they live in small family groups or herds.

Mammals, birds, reptiles, amphibians - all of them can be described for a very long time. We only briefly characterized the animals, described the existing units. The family of mammals is diverse and numerous, as you have just seen. We hope you found it useful to get to know him.