Although there are not so many mammals on our planet (about 4,500 species), they are still widespread and occupy a prominent place both on land, in the air, and in water, and even underground.

When we talk about wild or domestic animals, including our pets, we usually mean mammals or beasts.

Thus, animals are not only a lion, a wolf or a bear, but also a prickly hedgehog, and a small mouse, and a big good-natured elephant. These animals are called mammals because they feed their babies with milk.

Animals, like birds, are warm-blooded animals. They are able to keep their body temperature constant regardless of the temperature. environment, therefore, they can live both in the hot desert and in permafrost conditions, having adapted to severe frosts.

From overheating, the body of mammals is protected by sweating (which representatives of other classes of animals cannot do) and by evaporating moisture through the mucous membranes of the mouth (therefore, when it is hot, a dog breathes by sticking out its tongue). The body of mammals is also protected from cooling: for this, most animals are completely or partially covered with hair or fur (unlike the scales of fish, reptiles and bird feathers).

The wool (fur or hair) of animals can consist of a thick warm short undercoat and long hair, called guard hair, which give animals a protective color and are diverse in appearance (in hedgehogs they turn into needles, in pigs - into bristles).

Most mammals have claws (or nails) that help them move, hunt, and defend themselves from enemies. The hoof of cows, roe deer and other animals is also a modified claw that forms a horn shoe at the end of the finger. In many mammals, the claws are a climbing organ - they allow them to climb trees and rocks very quickly. Surprisingly, even ungulates can climb very well. Even such clumsy giants as an elephant, a hippopotamus or a rhinoceros can deftly climb very steep and winding mountain paths.

Mammals differ from other animals in the comprehensive development of the senses (sight, hearing, taste, smell - sharpness of smell, touch - the ability to recognize an object by touch, with the help of touch). They have a memory, some degree of prudence, have an idea of ​​time, color, are able to observe and even, in some cases, reason, thanks to which they skillfully use the accumulated experience.

Since man has all of the above characteristics, he also belongs to the class of 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 waters. 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 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. 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 by the 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. The respiratory system consists of 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 enters the bladder through two ureters, and from there through the urethra is periodically discharged to the outside. Sweat released from the sweat glands of the skin also removes a large number of salts from the body.

Metabolism. A more perfect structure of the digestive organs, lungs, heart and others ensures a high level of metabolism in animals. 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 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 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 into the blood of the embryo enter nutrients and oxygen, and carbon dioxide and other waste products harmful to the embryo 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 of the egg-laying order, or the first beasts - the 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 koala bear, marsupial anteaters. In marsupials, unlike the first animals, the development of the embryo occurs in the mother's body, in the uterus. But the placenta, or placenta, is absent, and therefore the cub does not stay long in the mother's body (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 dangerous diseases person. Known harm to the human economy is caused by some predatory mammals(in our country - a 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:

Detachments	Characteristic signs of units	Representatives
Insectivores	The teeth are of the same type, sharply tuberculate. The anterior end of the head is extended into a proboscis. The cerebral cortex is devoid of convolutions	Mole, hedgehog, desman
Bats	The forelimbs are transformed into wings (formed by leathery membranes). Bones thin and light (adaptation for flight)	Ushan, red evening
	The incisors are strongly developed, there are no fangs. Reproduce very quickly	Squirrel, beaver, mouse, chipmunk
Lagomorphs	The structure of the teeth are similar to rodents. In contrast, they have two pairs of incisors, one of which is located behind the other.	Hares, rabbit
	They feed mainly on live food. Strongly developed fangs and carnivorous teeth	wolf, fox, bear
pinnipeds	Most of their lives are spent in water. Both pairs of limbs are converted into flippers	Walrus, seal, cat
cetaceans	They live in water. The forelimbs are transformed into flippers, the hind limbs are reduced

In mammals, the spine is divided into five sections: cervical, thoracic, lumbar, sacral, and caudal. Only cetaceans do not have a sacrum. cervical 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.

Real ribs articulate only with the thoracic vertebrae (rudimentary may be on other vertebrae). In front, they are connected by the sternum, forming the chest. The shoulder girdle consists of two shoulder blades and two collarbones. Some mammals do not have clavicles (ungulates), in others they are 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 serve as mammals for movement on the ground, swimming, flight, grasping. 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 metacarpus bones corresponds to the number of fingers (no more than five). The thumb consists of two joints, the rest - of three. In cetaceans, the number of joints is increased.

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

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

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 down the ureters into the bladder. Urine comes out of it 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 folds with deep furrows in most mammalian species. The more folds and convolutions, the more complex and diverse the behavior of the animal. Also, mammals have a well-developed peripheral nervous system, which provides them with the highest speed of reflexes. The sense organs include: organs of vision, organs of hearing, organs of smell. The organs of vision are great importance in the life of mammals. Unlike birds, each eye of which sees objects separately, mammals have binocular vision. The auditory organs contain the external auditory meatus and the auricle. The olfactory organs are located in the anterior and posterior sections of the nasal cavity.

The digestive system of mammals is a gastrointestinal tract - a tube connecting the mouth to the anus. The digestive system includes: oral cavity, salivary glands, pharynx, esophagus, stomach, intestines, anus.

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

After entering the oral cavity, the food is chewed by the teeth. Then the food is moistened with saliva, which flows through the ducts from the 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. The salivary glands are 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 ensures that the food bolus enters the stomach.

Most mammals have a single chamber stomach. In its walls are glands that secrete digestive juice. But herbivorous mammals, such as deer, cow, goat, sheep, etc., have a multi-chambered stomach. The intestine is divided into thin and large. The small intestine includes the duodenum, jejunum, and ileum. To the thick - 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 section 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, there is an ileocecal valve that prevents the forming feces from being thrown back into the small intestine. In the caecum, under the influence of bacteria, there is a change in indigestible food substances. Also, in most mammals, there is a large amount of lymphatic tissue in the walls of the caecum, which makes it an important organ of the immune system. In many animals (for example, rabbits, beavers), the caecum is large. In some animals, it happens with an appendix. In the colon, the feces are dehydrated, accumulate in the rectum, and then are expelled out through the anus.

The ancestors of ancient mammals were animal-toothed reptiles. They are so named because they had a structure of teeth similar to mammals. In the course of evolution, a group of small animals separated from them, outwardly resembling egg-laying ones. In the process of natural selection, these animals developed a more developed brain, and, consequently, they were characterized by more complex behavior. At the end of the Mesozoic, after the extinction of the dinosaurs, ancient mammals settled in various habitats in terrestrial ecosystems.

Representatives of the class Mammals, or Beasts, are higher vertebrates, warm-blooded animals, whose body is covered with wool. Animals give birth to cubs and feed them with milk. They have a large brain with well-developed forebrain hemispheres. They are characterized by care for offspring and the most complex behavior. In the process of evolution, mammals have reached a huge diversity in connection with the formation of adaptations to different living conditions. About 4,000 are known. modern species.

When determining mammals, one should pay attention to: the color of the fur, the shape of the body and head, the length of the body and tail.

• Animals hunting at night usually have large eyes.
• Some animals have large ears 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 to maintain balance. In different animal species, tails vary in length and thickness.
• Most animals have a great sense of smell.
• The shape of the teeth depends on the food to which the animal is accustomed.
• The mustache helps the animal find its way, especially in a dark note.
• The mammary glands produce milk for offspring.
• Powerful aromatic glands under the tail allow the beast to mark the territory.
• The number of fingers on the paws different types different, so the animal is easy to identify by the trail.

The body of mammals consists of a head, neck, trunk, tail and two pairs of limbs. On the head, the facial and cranial regions are distinguished. In front is a mouth surrounded by soft lips. The eyes are protected by movable eyelids. Only mammals have an outer ear - the auricle.

The body of mammals is covered with hair, which reliably protects against sudden changes in temperature. Each hair grows from a hair follicle embedded in the skin. Hair, claws, nails, horns, hooves come from the same skin buds 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 them supple and waterproof. Sweat glands are involved in cooling the body and removing toxic substances. The mammary glands secrete milk.

The limbs of mammals are located not on the sides, as in 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 skull of the animals is large.

The teeth are differentiated into incisors, canines and molars, they are placed in recesses - alveoli. The cervical spine consists of seven vertebrae. The internal organs are protected by the chest. The sacral region 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 that allows the animal to make many complex movements and move actively.

Respiratory system

In mammals, a diaphragm appears - a muscular septum that separates the chest 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 a large amount of oxygen. In this regard, mammals have well-developed lungs.

Circulatory system

The circulatory system of mammals consists of two circles of blood circulation and a four-chambered heart. The movement of arterial and venous blood through the vessels ensures a rapid metabolism, due to which a constant body temperature is maintained.

Digestive system

The digestive system begins with the oral cavity. Here food is crushed, pounded with the help of teeth and moistened with saliva secreted by the salivary glands. In animals that feed on coarse plant foods, the stomach consists of several sections, the intestines are long. Various protozoa that decompose plant fiber live in the stomach and intestines.

In predators, the structure of the stomach is simpler and the intestines are shorter. All mammals have a well-developed liver and pancreas.

excretory system

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

Litter

Mammals leave litter in any weather. Litter of predators usually has an oblong shape and contains undigested remains of animals; the droppings of herbivores are most often rounded, with an admixture of plant fibers.

Nervous system

The nervous system, especially the brain, has received a high level of development in mammals. In the forebrain, due to the growth and thickening of the cortex, large hemispheres. In predatory mammals and monkeys, the cortex forms convolutions that increase its area. In this regard, animals have a complex behavior, there is a memory, elements of rational activity. They are able to report their condition, intentions, 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 growing generation and protect it until the cubs can fend for themselves. Cats, foxes and other predators teach their offspring to hunt. In small mammals, for example, in mice, there are several broods per year; offspring stay with their mother for only a few days, after which they begin an independent life.

breastfeeding

Feeding cubs with milk is a very important feature of mammals. Milk has a high nutritional value and contains all the necessary substances for the growth and development of the cub. The color of milk depends on the amount of fat. Fat is part of the milk in the form of microscopic droplets and therefore is 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 of mammals, they are divided into two subclasses: First beasts And Beasts.

First beasts

Representatives of the first animals lay eggs, which then incubate ( platypus) or worn in a bag on the belly (echidna). Hatching cubs lick the milk that is secreted on the mother's belly.

Beasts

Animals are divided into infraclasses Inferior, or marsupials, And Higher, or Placental.material from the site

marsupials

Marsupials, distributed mainly in Australia, give birth to small and helpless cubs. They are worn by the female in a bag 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 fetus in it is attached to the wall by the placenta and receives nutrients and oxygen from the mother through the umbilical cord.

Among the placental, a special detachment is distinguished Primates. It includes the most developed representatives of the animal world, most of which are monkeys. Humans are also included in this category.

Role in nature

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

Role in human life

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

Pictures (photos, drawings)

• 4.91. External structure mammal

• 

  4.92. mammalian skeleton

• 

  4.93. The circulatory system of a mammal

• 

  4.94. Digestive, respiratory and excretory systems of a mammal

• 

  4.95. The mammalian brain

• 
  

  4.96. Expression of emotions in a mammal

• 

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

• 

  4.98. Supposed appearance ancient mammal

• 

Mammals - on this moment the highest stage of evolution on our planet. This is a separate class of animals, which has a huge number of species, both land and sea. In particular, humans also belong to mammals.

In all the variety of mammalian species, which only animals are not found. For example, the pygmy shrew has a body size of only 3.5 cm and a weight of 1.5 g. Blue whale also refers to mammals, but with a body length of up to 33 meters, it has a mass of up to 120 tons. We constantly encounter representatives of this class of animals at home, on the street and in nature. These are almost all domestic animals, except for birds - cats, dogs, cows, horses, even stubborn mice and rats. Today, mammals are the dominant class of animals, of course, except for insects.

How to distinguish mammals from other classes of animals? They have some characteristics inherent in them alone. The name "mammals" itself indicates the main difference. Only they feed on milk, or rather, they feed their offspring with it. Other classes of animals do not do this, most of them do not care about the fate of their offspring at all.

Another important difference between mammals is a fairly developed central nervous system - it is this system that provides greater adaptability to different and rapidly changing conditions. The brain of mammals is well developed, and thanks to it the first species won the fight for survival. Reptiles, such as the once dominant dinosaurs, have a very primitive nervous system. It can only provide the simplest reflexes. For example, at largest dinosaur- diplodocus, which had a mass of tens of tons, and a body length of tens of meters, the size of the brain was no more chicken egg. Its device was primitive - much simpler than the brain of the smallest mammal.

An important feature of mammals is live birth. Cubs appear after a certain period of gestation. Development in the womb is also an important factor in adaptability. Of course, offspring are not as numerous as in reptiles or fish, in which one female is able to lay dozens of eggs and hundreds of eggs in the hope that at least half of them will survive. In mammals, intrauterine development until birth guarantees a high level of survival - the mother is able to take care of herself, unlike the newborn. Moreover, after the birth, the mother takes care of and teaches her children all the time of feeding.

All mammals are warm-blooded. This is another evolutionary step forward. Reptiles have an ambient temperature and a solid chitinous skin that only protects from damage. internal organs. Mammals are a completely different matter. They have a developed system of thermoregulation - in any conditions, the body temperature is constant. Even their skin is arranged differently. Only mammals have wool or hair, sebaceous and sweat glands - this is also part of the thermoregulation system. The brain has a separate part responsible for this. Another class of animals with a constant body temperature is birds, but they are also at the evolutionary stage between mammals and reptiles.

Mammals are distributed throughout the planet - from the South to the North Pole. In total, more than five thousand species are already known on Earth. Only 380 of them live permanently on the territory. But scientists are constantly finding new ones. After all, although it seems that everything has already been studied, that only it is possible, nature is still fraught with a lot of secrets. And we can say for sure that sooner or later evolution will step even further and mammals will be replaced by an even more developed class of animals. Maybe the brain of the person we now admire will be simpler than that of the most primitive of them, and they will already study us as an extinct species. It's just a matter of time, really...