What environments do mammals live in? Mammals

The ancestors of ancient mammals were reptiles with toothed teeth. They were so named because they had a tooth structure similar to mammals. During evolution, a group of small animals that looked like oviparous animals separated from them. Through the process of natural selection, these animals developed a more developed brain, and, therefore, they were characterized by more complex behavior. At the end of the Mesozoic, after the extinction of the dinosaurs, ancient mammals mastered various places habitats in terrestrial ecosystems.

Representatives of the class Mammals, or Animals, are higher vertebrates, warm-blooded animals, whose bodies are covered with hair. Animals give birth to cubs and feed them with milk. They have a large brain with well-developed forebrain hemispheres. They are characterized by caring for their offspring and the most complex behavior. In the process of evolution, mammals have achieved enormous diversity due to the formation of adaptations to different living conditions. About 4 thousand are known. modern species.

When identifying mammals, you should pay attention to: fur color, body and head shape, body and tail length.

• Animals that hunt at night usually have large eyes.
• Some animals have large ears in order to hear better.
• Wool allows the mammal to keep warm; in addition, coloring helps to hide from the eyes of enemies.
• The tail helps the animal maintain balance. Different species of animals have tails that vary in length and thickness.
• Most animals have an excellent sense of smell.
• The shape of the teeth depends on the food to which the animal is accustomed.
• Whiskers help the animal find its way, especially in the dark.
• The mammary glands produce milk for the offspring.
• Powerful aromatic glands under the tail allow the animal to mark its territory.
• Number of toes on paws different types different, so the animal is easy to identify by its tracks.

The body of mammals consists of a head, neck, torso, tail and two pairs of limbs. On the head there are facial and cranial sections. The mouth is located in front, surrounded by soft lips. The eyes are protected by movable eyelids. Only mammals have an external ear - the auricle.

The body of mammals is covered with hair, which reliably protects against sudden temperature changes. Each hair grows from a hair follicle embedded in the skin. Hair, claws, nails, horns, hooves come from the same skin rudiments as reptile scales. The skin of mammals is rich in glands. The secretions of the sebaceous glands located at the base of the hair lubricate the skin and hair, making it elastic and waterproof. Sweat glands are involved in cooling the body and excreting toxic substances. The mammary glands secrete milk.

The limbs of mammals are not located on the sides, like those of amphibians and reptiles, but under the body. Therefore, the body is raised above the ground. This makes it easier to move on land.

Musculoskeletal system

The skeleton of mammals, like all terrestrial vertebrates, consists of five sections, but has a number of characteristic features. The animals have large skulls.

The teeth are differentiated into incisors, canines and molars, and are placed in recesses - alveoli. The cervical spine consists of seven vertebrae. Internal organs protects the chest. The sacral section fuses with the bones of the pelvis. The number of vertebrae in the caudal region depends on the length of the tail. The skeleton and the muscles attached to its bones make up a powerful musculoskeletal system, allowing the animal to make many complex movements and move actively.

Respiratory system

In mammals, a diaphragm appears—a muscular septum that separates the thoracic cavity from the abdominal cavity. Due to it, animals can further reduce or increase the volume of the chest.

When muscles work intensively, the body requires large number oxygen. In this regard, mammals have well-developed lungs.

Circulatory system

Circulatory system mammals consists of two blood circulation circles and a four-chambered heart. The movement of arterial and venous blood through the vessels ensures rapid metabolism, thereby maintaining a constant body temperature.

Digestive system

The digestive system begins with the oral cavity. Here the food is crushed, ground with the help of teeth and moistened with saliva secreted by the salivary glands. In animals that eat rough plant feed, the stomach consists of several sections, and the intestines are long. The stomach and intestines are home to various protozoa that decompose plant fiber.

Carnivores have a simpler stomach structure and shorter intestines. All mammals have a well-developed liver and pancreas.

Excretory system

The excretory organs of mammals are two kidneys. The urine formed in them flows through the ureters into the bladder, and from there it is periodically excreted.

Litter

Mammals leave droppings in any weather. Predator droppings usually have an oblong shape and contain undigested animal remains; The droppings of herbivores are most often round, with an admixture of plant fibers.

Nervous system

High level developed in mammals nervous system, especially the brain. In the forebrain, due to the growth and thickening of the cortex, the cerebral hemispheres developed. In carnivorous mammals and monkeys, the cortex forms convolutions that increase its area. In this regard, animals have complex behavior, they have memory, and elements of rational activity. They are able to communicate their state, intentions, and express emotions. The degree of development of the sense organs depends on the lifestyle and habitat of a particular species.

The cubs of most animals develop in the mother's body and are born fully formed. The mother feeds them with milk. Mothers, and sometimes fathers, look after the younger generation and protect it until the cubs can fend for themselves. Cats, foxes and other predators teach their offspring to hunt. Small mammals, for example, mice, have several broods per year; the offspring stays with their mother for only a few days, after which they begin an independent life.

Milk feeding

Feeding babies with milk is very important feature mammals. Milk is highly nutritious and contains all the necessary substances for the growth and development of the baby. The color of milk depends on the amount of fat. Fat is included in milk in the form of microscopic droplets and is therefore easily digested and absorbed in the baby’s body.

Ecological groups of mammals

Adaptation to the environment

Depending on the characteristics of the processes of reproduction and development, mammals are divided into two subclasses: Primordial beasts And Animals.

Primordial beasts

Representatives of the first animals lay eggs, which they then incubate ( platypus) or carried in a pouch on the belly (echidna). The hatched cubs lick the milk, which is released onto the mother's belly.

Animals

Animals are divided into infraclasses Inferior, or Marsupials, And Highest, or Placental.Material from the site

Marsupials

Marsupials, distributed mainly in Australia, give birth to small and helpless cubs. They are carried by the female in a pouch for several months, attached to the nipple of the mammary gland.

Placental

Placentals have a special organ for the development of a fertilized egg - the uterus. The embryo in it is attached to the wall by the placenta and receives nutrients and oxygen from the mother through the umbilical cord.

Among the placentals, the order is especially distinguished Primates. It includes the most developed representatives of the animal world, most of which are monkeys. This order also includes humans.

Role in nature

Representatives of mammals differ from each other in their lifestyle, the type of food they consume, and therefore perform different functions in ecosystems. Herbivorous mammals are primary consumers organic matter. Predatory animals help regulate the number of herbivorous animals. Many rodents and insectivorous mammals participate in soil formation. The passages they create in the soil contribute to its enrichment with moisture, air, organic and inorganic substances.

Role in a person's life

Man began to domesticate mammals and birds about 15 thousand years ago. Probably the first domestic animal was the dog, then the goat, sheep, and cattle were domesticated. The domestication of animals led to sedentism, and people began to engage in animal husbandry and agriculture.

Pictures (photos, drawings)

• 4.91. External structure mammal

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  4.92. Mammal skeleton

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  4.93. Mammalian circulatory system

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  4.94. Digestive, respiratory and excretory system mammal

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  4.95. Mammal brain

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  4.96. Expression of emotions in a mammal

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  4.97. Representatives of mammals: a) primal beast (echidna); b) lower animals - marsupials (kangaroos)

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  4.98. Supposed appearance ancient mammal

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Quite difficult: different scientists have their own views on which animals belong to a certain order, superorder, clade, group and all the other complex terms that biologists use when untangling the branches of the tree of life. To make the classification a little easier, in this article you will discover an alphabetical list and characteristics of mammal orders, which most scientists agree with.

Afrosoricides and insectivores

An order of mammals formerly known as insectivores ( insectivora), has undergone great changes in lately, splitting into two new orders: insectivores ( Eulipotyphia) and Afrosoricides ( Afrosoricida). In the last category are two very obscure creatures: bristly hedgehogs from southern Africa and golden mole from Africa and Madagascar.

Common tenrec

To the squad Eulipotyphia includes hedgehogs, slittooths, shrews and moles. All members of this order (and most Afrosoricidae) are tiny, narrow-nosed, insectivorous animals with bodies covered in thick fur or spines.

Armadillos and edentates

Nine-banded armadillo

The ancestors of armadillos and edentates first arose in South America about 60 million years ago. Animals from these orders are characterized by an unusual shape of their vertebrae. Sloths, armadillos and anteaters, which belong to the superorder edentates ( Xenarthra), have the most sluggish metabolism of any other living mammal. Males have internal testes.

Today, these animals are on the edge of the mammalian class, but back in the day, they were among the largest organisms on Earth, as evidenced by the five-ton prehistoric sloth Megatherium, as well as the two-ton prehistoric armadillo Glyptodon.

Rodents

Spiny mouse

The largest order of mammals, consisting of more than 2,000 species, includes squirrels, dormice, mice, rats, gerbils, beavers, ground squirrels, kangaroo hoppers, porcupines, striders and many others. All these tiny, furry animals have teeth: one pair of incisors in the upper and lower jaws? and a large gap (called a diastema) located between the incisors and molars. The incisors grow continuously and are constantly used to grind food.

Hyraxes

Bruce's hyrax

Hyraxes are thick, short-legged, herbivorous mammals, which look a bit like a cross between a domestic cat and a rabbit. There are four (according to some sources five) species of hyraxes: tree hyrax, western hyrax, Cape hyrax and Bruce hyrax, all of which are native to Africa and the Middle East.

One of the strangest features of hyraxes is their relative lack of internal temperature regulation; They are warm-blooded, like all mammals, but at night they gather in groups to keep warm, and during the day they warm up in the sun for a long time, like reptiles.

Lagomorpha

Even after centuries of study, scientists are still not sure what to do with hares, rabbits and pikas. These small mammals are similar to rodents, but have some important differences: lagomorphs have four, rather than two, incisors in the upper jaw, and they are strict vegetarians, whereas mice, rats and other rodents tend to be .

Lagomorphs can be identified by their short tails, long ears, slit-like nostrils which they can close, and (in some species) a strong tendency to move by jumping.

Caguanas

Malayan woolwing

Never heard of kaguans? And this is possible, because on our planet there are only two living species of woolly wings left, which live in dense jungles Southeast Asia. Caguans have a wide membrane of skin that connects all the limbs, tail and neck, which allows them to glide from one tree to another, a distance of about 60 m.

Oddly enough, molecular analysis has demonstrated that caguans are the closest living relatives of our own order of mammals, the primates, but their parenting behavior is most similar to marsupials!

Cetaceans

The order includes almost a hundred species and is divided into two main suborders: toothed whales (including sperm whales, beaked whales, killer whales, as well as dolphins and porpoises) and baleen whales (smooth, gray, dwarf and striped whales).

These mammals are characterized by their flipper-like forelimbs, reduced hind limbs, streamlined bodies, and a massive head that extends into a “beak.” Cetacean blood is unusually rich in hemoglobin, and this adaptation allows them to remain underwater for long periods of time.

Odd-toed ungulates

Compared to their equivalent artiodactyl cousins, they are a rare order, consisting exclusively of horses, zebras, rhinoceroses and tapirs - about 20 species in total. They are characterized by an odd number of fingers, as well as a very long intestine and a single-chamber stomach containing specialized ones that help digest tough vegetation. Oddly enough, according to molecular analysis, equid mammals may be more closely related to carnivores (order Carnivora) than to artiodactyl mammals.

Monotreme or oviparous

These are the most bizarre mammals on our planet. They include two families: platypus and echidnaidae. These females do not give birth to live young. Monotremes are also equipped with cloacas (a single opening for urination, defecation and reproduction), they are completely toothless and have electroreceptors, thanks to which they can sense weak electrical signals from afar. Scientists believe that monotremes are from an ancestor living in, which preceded the split of placental and marsupial mammals, hence their uniqueness.

Pangolins

Steppe lizard

Also known as pangolins, pangolins have large, horny, diamond-shaped scales (made of keratin, the same protein as human hair) that overlap and cover their bodies. When these creatures are threatened by predators, they curl into tight balls, and if they feel threatened, they emit a foul-smelling liquid from their anal glands. Pangolins are native to Africa and Asia, and are almost never found in the Western Hemisphere except in zoos.

Artiodactyls

Mountain goat

They are placental mammals that have developed third and fourth toes, covered with a thick, horny hoof. Artiodactyls include fauna such as cows, goats, deer, sheep, antelope, camels, llamas, pigs, etc., accounting for about 200 species worldwide. Almost all artiodactyls are herbivores (with the exception of omnivorous pigs and peccaries); some representatives of the order, like cows, goats and sheep, are ruminants (mammals equipped with additional stomachs).

Primates

Pygmy marmoset

It includes about 400 species and in many respects its representatives can be considered the most “advanced” mammals on the planet, especially with regard to the size of their brains. Non-human primates often form complex social units and are capable of tool use, and some species have dexterous hands and prehensile tails. There is no single feature that defines all primates as a group, but these mammals have common features, such as binocular vision, hair, limbs with five fingers, fingernails, developed cerebral hemispheres, etc.

Jumpers

Short-eared jumper

Hoppers are small, long-nosed, insectivorous mammals native to Africa. Currently, there are about 16 species of jumpers, which are grouped into 4 genera, such as: proboscis blenny, forest jumper, long-eared jumper and short-eared jumper. Classification of these small mammals was the subject of discussion; in the past they were presented as close relatives of ungulate mammals, lagomorphs, insectivores and tree shrews (recent molecular evidence suggests a relationship with elephants).

Chiroptera

Spectacled flying fox

Representatives of the order are the only mammals that are capable of active flight. The order Chiroptera includes about a thousand species, divided into two main suborders: Megachiroptera(mergans) and Microchiroptera(bats).

Fruit bats also known as flying foxes, have a large body size relative to bats, and eat only fruits; Bats are much smaller and have a more varied diet, ranging from the blood of grazing animals, insects, and flower nectar. Most bats, and very few fruit bats, have the ability to echolocate - that is, they pick up high-frequency sound waves from their environment to navigate in dark caves and tunnels.

Sirens

Semi-marine mammals known as pinnipeds (including seals, sea ​​lions and walruses) belong to the order Carnivores (see below), but dugongs and manatees belong to their own order Sirens. The name of this unit is associated with the sirens from Greek mythology. Apparently starving Greek sailors mistook dugongs for mermaids!

Sirens are characterized by their lobed tails, almost vestigial hind limbs, and muscular forelimbs that allow them to control their bodies underwater. Modern dugongs and manatees have small body sizes, but are nevertheless members of a recently extinct family sea ​​cows may have weighed up to 10 tons.

Marsupials

An infraclass of mammals that, unlike placental mammals, do not carry their young in the womb, but incubate them in specialized pouches after an extremely short interval of internal pregnancy. Everyone is familiar with kangaroos, koalas and wombats, but possums are also marsupials, and for millions of years the largest marsupials on Earth lived in South America.

In Australia, marsupials managed to displace placental mammals for most of the time. the only exceptions there were the jerboa mice that made their way from Southeast Asia, and the dogs, cats, and livestock introduced to the continent by European settlers.

Aardvarks

Aardvark

The aardvark is the only living species in the order Aardvarks. This mammal is characterized by its long snout, arched back and coarse fur, and its diet consists mainly of ants and termites, which it preys on by tearing apart insect nests with its long claws.

Aardvarks live in forests and grasslands south of the Sahara, their range extends from southern Egypt to the Cape of Good Hope, in the south of the continent. The aardvark's closest living relatives are artiodactyls and (somewhat surprisingly) whales!

Tupaii

Indonesian tupaya

This order includes 20 species of tupai that are native to tropical forests Southeast Asia. Representatives of this order are omnivores, and eat everything from insects to small animals, and flowers such as. Ironically, they have the highest brain-to-body ratio of any living mammal (including humans).

Predatory

and domestic cats), but also hyenas, civets and mongooses.

Canids include dogs, wolves, as well as bears, raccoons and many other carnivores, including seals, sea ​​lions and walruses. As you may have guessed, carnivores are characterized by sharp teeth and claws; they also possess at least four toes on each foot.

Proboscis

Savannah elephant

You may be surprised to learn that all the worlds from the order are divided into only three species (or according to some sources two): African savannah elephant, African forest elephant and Indian elephant.

In mammals, the spine is divided into five sections: cervical, thoracic, lumbar, sacral and caudal. Only cetaceans do not have a sacrum. The cervical region almost always consists of seven vertebrae. Thoracic - from 10-24, lumbar from 2-9, sacral from 1-9 vertebrae. Only in the caudal region their number varies greatly: from 4 (in some monkeys and humans) to 46.

True ribs articulate only with the thoracic vertebrae (rudiments can also be on other vertebrae). They are connected in front by the sternum, forming the rib cage. The shoulder girdle consists of two shoulder blades and two clavicles. Some mammals do not have clavicles (ungulates), while others have them poorly developed or replaced by ligaments (rodents, some carnivores).

The pelvis consists of 3 pairs of bones: iliac, pubic and ischial, which are tightly fused together. Cetaceans do not have a true pelvis.

The forelimbs are used by mammals to move on land, swim, fly, and grasp. The humerus is greatly shortened. The ulna is less developed than the radius and serves to articulate the hand with the shoulder. The hand of the forelimb consists of the wrist, metacarpus and fingers. The wrist consists of 7 bones arranged in two rows. The number of metacarpal bones corresponds to the number of fingers (no more than five). Thumb consists of two joints, the rest - of three. In cetaceans, the number of joints is increased.

In the hind limbs, the femur is shorter than the tibia in most mammals.

Respiratory system mammals consists of the larynx and lungs. The lungs are characterized by a large branching of the bronchi. The thinnest of them are the bronchioles. At the ends of the bronchioles there are thin-walled vesicles (alveoli), densely entwined with capillaries. The diaphragm is a characteristic anatomical feature of mammals. Plays an important role in the breathing process.

The kidneys in mammals are bean-shaped and located in the lumbar region, on the sides of the spine. In the kidneys, as a result of blood filtration, urine is formed, then it flows through the ureters into the bladder. From it, urine exits through the urethra.

In mammals, the forebrain and cerebellum are especially developed. The cerebral cortex is formed by several layers of bodies nerve cells and covers the entire forebrain. It forms folds and convolutions with deep grooves in most mammalian species. The more folds and convolutions, the more complex and varied the animal’s behavior. Mammals also have a well-developed peripheral nervous system, which provides them with highest speed reflexes. The sense organs include: organs of vision, organs of hearing, organs of smell. The organs of vision have great value in the life of mammals. Unlike birds, whose each eye sees objects separately, mammals have binocular vision. The hearing organs contain the external auditory canal and the auricle. The olfactory organs are located in the anterior and posterior sections of the nasal cavity.

The digestive system of mammals is the gastrointestinal tract, a tube that connects the mouth to the anus. TO digestive system include: oral cavity, salivary glands, pharynx, esophagus, stomach, intestines, anus.

Most mammals have teeth (except for monotremes, some cetaceans, lizards and anteaters). They are located in the cells of the jaw bones. There are four types of teeth: incisors, canines, false molars and true molars.

After entering the oral cavity, food is chewed with the teeth. The food is then moistened with saliva, which flows through the ducts from salivary glands. This makes it easier to swallow and move down the esophagus. Under the influence of saliva complex carbohydrates(starch, sugar) contained in food are converted into less complex ones. Salivary glands highly developed in herbivores. A cow, for example, secretes 60 liters of saliva per day. In most animals, saliva has pronounced antiseptic properties.

The esophagus allows the bolus of food to enter the stomach.

Most mammals have a single-chamber stomach. In its walls there are glands that secrete digestive juice. But herbivorous mammals like deer, cow, goat, sheep, etc. have a multi-chambered stomach. The intestine is divided into thin and thick. The small intestine includes the duodenum, jejunum and ileum. To the colon - the cecum, colon and rectum.

In the small intestine, food is digested under the influence of digestive juices. They are secreted by the glands of the intestinal walls, as well as by the liver and pancreas, which open into the initial part of the small intestine - the duodenum. Nutrients in the small intestine are absorbed into the blood, and the remains of undigested food enter the large intestine.

At the junction of the small and large intestines, the ileocecal valve is located, which prevents the forming feces from being thrown back into the small intestine. In the cecum, under the influence of bacteria, indigestible food substances change. Also, most mammals have a large amount of lymphatic tissue in the walls of the cecum, which makes it an important organ of the immune system. In many animals (for example, rabbits, beavers) the cecum has large sizes. In some animals it occurs with the appendix. In the colon, stool is dehydrated, accumulates in the rectum and is then expelled through the anus.

Mammals are the most highly organized class of vertebrates. They are characterized by a highly developed nervous system (due to an increase in the volume of the cerebral hemispheres and the formation of the cortex); relatively constant body temperature; four-chambered heart; the presence of a diaphragm - a muscular septum separating the abdominal and thoracic cavities; development of the young in the mother's body and feeding with milk (see Fig. 85). The body of mammals is often covered with fur. The mammary glands appear as modified sweat glands. The teeth of mammals are unique. They are differentiated, their number, shape and function vary significantly among different groups and serve as a systematic feature.

The body is divided into head, neck and torso. Many have a tail. Animals have the most perfect skeleton, the basis of which is the spinal column. It is divided into 7 cervical, 12 thoracic, 6 lumbar, 3-4 fused sacral and caudal vertebrae, the number of the latter varies. Mammals have well-developed senses: smell, touch, vision, hearing. There is an auricle. The eyes are protected by two eyelids with eyelashes.

With the exception of oviparous mammals, all mammals bear their young in uterus- a special muscular organ. The cubs are born alive and are fed milk. Offspring of mammals to a greater extent needs further care than other animals.

All of these characteristics allowed mammals to gain a dominant position in the animal world. They are found all over the globe.

The appearance of mammals is very diverse and is determined by their habitat: aquatic animals have a streamlined body shape, flippers or fins; land dwellers have well-developed limbs and a dense body. The inhabitants air environment the front pair of limbs are transformed into wings. A highly developed nervous system allows mammals to better adapt to environmental conditions and promotes the development of numerous conditioned reflexes.

The class of mammals is divided into three subclasses: oviparous, marsupials and placentals.

1. Oviparous, or primal beasts. These animals are the most primitive mammals. Unlike other representatives of this class, they lay eggs, but feed their young with milk (Fig. 90). They have preserved the cloaca - a part of the intestine where three systems open - digestive, excretory and reproductive. Therefore they are also called monotreme. In other animals these systems are separated. Oviparous species are found only in Australia. These include only four species: echidnas (three species) and the platypus.

2. Marsupial mammals more highly organized, but they are also characterized by primitive features (see Fig. 90). They give birth to live, but underdeveloped young, practically embryos. These tiny cubs crawl into a pouch on the mother's belly, where, feeding on her milk, they complete their development.

Rice. 90. Mammals: oviparous: 1 - echidna; 2 - platypus; marsupials: 3 - opossum; 4 - koala; 5 - dwarf marsupial squirrel; 6 - kangaroo; 7 - marsupial wolf

Australia is home to kangaroos, marsupial mice, squirrels, anteaters (nambats), marsupial bears(koala), badgers (wombats). The most primitive marsupials live in Central and South America. This is an opossum, a marsupial wolf.

3. Placental animals have a well developed placenta- an organ attached to the wall of the uterus and performing the function of metabolism nutrients and oxygen between the mother’s body and the embryo.

Placental mammals are divided into 16 orders. These include Insectivores, Chiroptera, Rodents, Lagomorphs, Carnivores, Pinnipeds, Cetaceans, Ungulates, Proboscideans, and Primates.

Insectivores mammals, which include moles, shrews, hedgehogs, etc., are considered the most primitive among placentals (Fig. 91). These are quite small animals. The number of teeth they have is from 26 to 44, the teeth are undifferentiated.

Chiroptera- the only flying animals among animals. They are mainly crepuscular and nocturnal animals that feed on insects. These include fruit bats, bats, noctule bats, and vampires. Vampires are bloodsuckers; they feed on the blood of other animals. Bats have echolocation. Although their eyesight is poor, due to their well-developed hearing, they catch the echo of their own squeak reflected from objects.

Rodents- the most numerous order among mammals (about 40% of all animal species). These are rats, mice, squirrels, gophers, marmots, beavers, hamsters and many others (see Fig. 91). Characteristic feature Rodents have well-developed incisors. They have no roots, grow throughout their lives, wear down, and have no fangs. All rodents are herbivores.

Rice. 91. Mammals: insectivores: 1 - shrew; 2 - mole; 3 - tupaya; rodents: 4 - jerboa, 5 - marmot, 6 - nutria; lagomorphs: 7 - brown hare, 8 - chinchilla

Close to rodents squad lagomorphs(see Fig. 91). They have a similar tooth structure and also eat plant matter. These include hares and rabbits.

To the squad predatory belongs to more than 240 species of animals (Fig. 92). Their incisors are poorly developed, but they have powerful fangs And carnassial teeth, used for tearing animal meat. Predators feed on animal and mixed food. The order is divided into several families: canids (dog, wolf, fox), bears ( polar bear, brown bear), felids (cat, tiger, lynx, lion, cheetah, panther), mustelids (marten, mink, sable, ferret), etc. Some predators are characterized by hibernation(bears).

Pinnipeds They are also predatory animals. They have adapted to life in water and have specific features: the body is streamlined, the limbs are turned into flippers. The teeth are poorly developed, with the exception of the fangs, so they only grab food and swallow it without chewing. They are excellent swimmers and divers. They feed mainly on fish. They breed on land, along seashores or on ice floes. The order includes seals, walruses, fur seals, sea lions, etc. (see Fig. 92).

Rice. 92. Mammals: carnivores: 1 - sable; 2 - jackal; 3 - lynx; 4 - black bear; pinnipeds: 5 - harp seal; 6 - walrus; ungulates: 7 - horse; 8 - hippopotamus; 9 - reindeer; primates: 10 - marmoset; 11 - gorilla; 12 - baboon

To the squad cetaceans also include inhabitants of the waters, but, unlike pinnipeds, they never go onto land and give birth to their young in the water. Their limbs have turned into fins, and their body shape resembles fish. These animals mastered the water for the second time, and in connection with this they acquired many features characteristic of aquatic inhabitants. However, they retained the main features of the class. They breathe atmospheric oxygen through the lungs. Cetaceans include whales and dolphins. The blue whale is the largest of all modern animals (length 30 m, weight up to 150 tons).

Ungulates are divided into two orders: equids and artiodactyls.

1. TO equid include horses, tapirs, rhinoceroses, zebras, donkeys. Their hooves are modified middle toes, with the remaining toes reduced to varying degrees in different species. Ungulates have well-developed molars, as they feed on plant foods, chewing and grinding them.

2. U artiodactyls the third and fourth toes are well developed, transformed into hooves, which bear the entire weight of the body. These are giraffes, deer, cows, goats, sheep. Many of them are ruminants and have a complex stomach.

To the squad proboscis belong to the largest of land animals - elephants. They live only in Africa and Asia. The trunk is an elongated nose fused with upper lip. Elephants do not have tusks, but their powerful incisors have turned into tusks. In addition, they have well-developed molars that grind plant foods. Elephants change these teeth 6 times during their life. Elephants are very voracious. One elephant can eat up to 200 kg of hay per day.

Primates combine up to 190 species (see Fig. 92). All representatives are characterized by a five-fingered limb, grasping hands, and nails instead of claws. The eyes are directed forward (primates have developed binocular vision). |
§ 64. Birds9. Fundamentals of ecology

The most successful group in the animal kingdom are mammals. In this article we will briefly talk about the characteristics of these animals, clarify which orders belong to mammals, and determine their habitats.

Features of mammals

This class of vertebrates belongs to the superclass of tetrapods, in which there are about 5.5 thousand species, including Homo sapiens. The main feature of the representatives of the “Mammals” group is feeding their young with milk.
In addition, there are the following signs:

• warm-blooded;
• live birth;
• the body is covered with hair, sweat and sebaceous glands, and horny formations are developed;
• the skull has a zygomatic arch;
• the spine is clearly divided into five sections;
• vertebrae of platycelial type;
• the subcutaneous muscles are highly developed, there is a diaphragm;
• a highly developed nervous system, which allows you to quickly respond to stimuli from the external environment;
• special structure of the hearing organ;
• the lungs have an alveolar structure;
• the heart is four chambered, the blood circulation is divided into two circles;
• unique structure of jaws and teeth.

The physiology of mammals is not particularly different from other four-legged representatives, but due to the high development of certain organ systems, this class is considered the highest highly organized among animals.

The Latin name of this class is Mammalia, which is derived from the Latin “mamma” – breast, udder. The Russian word “mammals” means milk-feeding.

Spreading

Representatives of the class can be found everywhere. The only places where there are no mammals are deep ocean and Antarctica, although seals and whales can be found off its coast.

Many subtypes are limited in distribution due to their attachment to environmental conditions. For many animals, temperature, soil and orographic conditions, as well as the availability of food are important.

The separate class “Mammals” was first described by Carl Linnaeus in 1758. At that time, there were 184 species; in modern times, all species are divided into 26-29 orders, which consist of 153 families, divided into 1229 genera.

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According to the traditional classification, this class of vertebrates is divided into the subclasses “Primal Beasts” (Prototheria) and “Beasts” (Theria). The latter, in turn, are divided into two infraclasses: Marsupials and Placentals.

Rice. 1. Classification.

Description of orders of mammals

All representatives of the class are quite diverse in external signs. The traditional body structure, which consists of a head, neck, torso, two pairs of limbs and a tail, varies in the ratio of shapes and sizes. So, a shining example there may be such variations long neck giraffe, and whales lacking necks.

Rice. 2. External structure.

The order Chiroptera is very different from other mammals due to the transformation of the forelimbs into wings. Due to this, in the popular classification, bats were classified as birds.

The record holders for size and body weight are: the dwarf shrew (weight up to 1.7 g, length up to 4.5 cm), savannah elephant (weight up to 5 tons, shoulder height up to 4 m), blue whale(length - 33 m, weight - up to 1.5 tons).

The list of mammals in Russia includes about 300 species. You can see their list in the following table:

Squad	Family	Genus	Representatives
			Common flying squirrel
			Common squirrel
		Chipmunks	Asian chipmunk
			Long-tailed ground squirrel, Caucasian ground squirrel
			Steppe, Kamchatka, Altai marmot
		Hazel, forest, garden dormouse
		Sleepyheads	Sonya the Regiment
	Beavers		Canadian beaver, river beaver
	Mousebirds		Forest mouse, steppe mouse, Caucasian mouse, etc.
	Jerboa	Jerboas	Large and small jerboas
	Mole rats		Common mole rat, Ural
	Hamsters		Common hamster
		Mole voles	Mole voles
			Forest, Siberian, Promethean voles
		Oriental, forest, house mice	Field, small, forest, house mice
			Gray and black rats
Lagomorpha	Zaitsevy		Brown hare, mountain hare, bush hare
			Wild rabbit
			Altai, northern, small pika
Insectivores		Common hedgehogs	European hedgehog
		Eared hedgehogs	long eared hedgehog
	Moles	Common moles
		Muskrat	Russian muskrat
	Shrews	Shrews	Siberian, long-tailed shrew
		Shrews	Far Eastern, giant, and average shrews
Chiroptera	Horseshoe-nosed	Horseshoe bats	Southern, great horseshoe bat
	Smooth-nosed		Long-eared, Amur bat
		Vechernitsy	Red-haired, oriental noctule
			Desert leather, leather jackets
	Raccoons		Raccoon
		Raccoon dogs	Raccoon dog
		Wolves and dogs	Jackal, wolf
			Fox, corsac dog
	Bearish		White, brown bear
	Marten		Kharza, sable, martens
		Caresses and hori	Weasel, ermine
			Forest, steppe cat
Odd-toed ungulates	Equine		wild horse
Artiodactyls			Wild boar
		Deer, roe deer, moose	Reindeer, European roe deer, elk
	Bovids	Mountain goats, sheep	Siberian goat, mountain sheep
Cetaceans	Dolphinidae	Common dolphins, killer whales, whales	Dolphins, killer whales, whales

Rice. 3. Diversity of mammals.

What have we learned?

The most highly developed group of animals are mammals. Representatives of this class can be found everywhere. They gained a leading position due to a number of their physiological and external features. Their main characteristics are feeding their offspring with milk, as well as being warm-blooded.

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