Amphibians- a small group of vertebrates, occupying an intermediate position between fish and true terrestrial chordates. The vast majority of amphibians live, depending on the stages of the life cycle, either in water or on land, therefore amphibians are classified as semi-aquatic, semi-terrestrial chordate animals. This class of terrestrial animals has retained a very close relationship with the aquatic environment.

The paired five-fingered limbs characteristic of terrestrial animals testify to the adaptability to a terrestrial way of life. Their limbs consist of three sections (the forelimb - from the shoulder, forearm and bone, the back - has a thigh, lower leg, foot). The hand and foot end in fingers. Breathe lightly and with moist skin. They have two circles of blood circulation and a three-chambered heart. They reproduce and develop in water. The larva is equipped with gills. Adult amphibians retain a number of traits inherited from their fish-like ancestors. First of all, it is a large number of mucous glands in the skin, which help keep it moist. The skin is an important respiratory organ in amphibians, but when dry, it cannot perform a respiratory function, since oxygen diffusion occurs only through the water film. This explains the richness of the amphibian fauna in the warm and humid regions of the globe.

The origin of amphibians from fish is also evidenced by the method of reproduction. Amphibians lay eggs that are poor in nutrients and unprotected from the environment, as a result of which eggs can only develop in water. Just like fish, amphibians are characterized by external fertilization of eggs. An even greater resemblance to fish is found in amphibian larvae - tadpoles. Their respiratory organs are gills, first external, then internal; the heart of the larvae is two-chambered and one circle of blood circulation. The organ of the lateral line is preserved on the body, the organ of movement is the tail, surrounded by a swimming membrane.

pond frog

Adult amphibians, typified by pond frog, has a short and wide body. The neck is not pronounced. Above the mouth are the nostrils, a little behind - the eyes, which have eyelids that protect the eyes from drying out (adaptation to life on land). Behind the eyes are the organs of hearing, consisting of the middle ear, closed by the tympanic membrane, and the inner ear. The body rests on two pairs of limbs. The rear ones are the most developed. With their help, the frog moves by jumping on land and swims well. This is facilitated by the presence of a swimming membrane between the fingers.

frog skeleton

frog skeleton consists of a small brain box(evidence of poor brain development) and short spine. The skeletons of the limbs consist of three sections, which are mobile due to the connection with the help of joints. The forelimb is attached to the shoulder girdle, which consists of chest, two crow bones, clavicle and two shoulder blades. The hind limbs are connected to the spine by pelvic girdle, formed by fused pelvic bones. The muscles of the frog are especially developed in the region of the belts and especially in the free limbs.

Digestive system of a frog

Digestive system of a frog very similar to that of fish, only in amphibians hindgut does not open outwards, but into its special extension - cloaca. The cloaca open ureters and excretory ducts reproductive organs. The frog catches its prey with the help of sticky tongue, which is attached in the mouth by the anterior end. The frog usually swallows the captured food (insects) whole

Frog respiratory organs

Frog respiratory organs - lungs and wet skin. Through nostrils air enters the oral cavity, and from there - into lungs. Exhalation occurs as a result of contractions of the muscles of the ventral side of the frog. Mucus-covered skin with a well-developed capillary system promotes skin respiration.

Frog circulatory system

Frog circulatory system has a more complex structure. Appearance two circles of blood circulation led to a more complex structure. hearts. It consists of three chambers: ventricle and two atrial. The right atrium contains only venous blood saturated with carbon dioxide, and the left atrium contains only arterial blood; blood mixes in the ventricle. Arterial, oxygenated blood is supplied to the brain of the frog, while the whole body receives mixed blood. Through a large circle of blood circulation, blood from the ventricle is sent through the arteries to all organs and tissues, and from them through the veins flows into the right atrium. Through the pulmonary circulation, blood from the ventricle enters the lungs and skin, and from the lungs returns to the left atrium.

Frog excretory organs

Frog excretory organs - kidneys, ureters, bladder. The kidneys produce urine, which flows through the ureters to the cloaca, and from it to the bladder. As it fills, urine is removed through the cloaca to the outside.

Nervous system of a frog

Central nervous system of amphibians consists of the same sections as in fish, but the forebrain is more developed, it can be distinguished large hemispheres. The cerebellum is less developed than in fish, due to the simpler and more uniform movements of amphibians.

Reproduction and development of the frog

After waking up from hibernation, frogs leave deep water bodies, moving to shallow ponds, ditches, puddles and floods of melt water well warmed up by the sun. Here the females spawn, very similar to fish eggs, and the males pour their seminal fluid over it. Spermatozoa penetrate the eggs and fertilize them. The shells of eggs in water swell greatly, become transparent, stick together with each other, forming lumps, and float to the surface or attach to underwater objects. After fertilization, the larvae begin to develop rapidly, as a result, a multicellular germ. After 12-25 days, a larva appears from the egg - tadpole.

The tadpole initially has a tail and resembles a fish fry. Its tail is surrounded by a thin swimming membrane. The tadpole breathes with three pairs of feathery gills located on the sides of the head. It has lateral line organs in its skin. The mouth and limbs are initially absent. After some time, a mouth begins to erupt with two horny plates and denticles on the lips, with which the tadpole scrapes off the plants that serve as food for it. Then the outer gills disappear and the inner gills develop. At this stage of development, the tadpole is especially similar to a fish. At this time, he developed a chord, a two-chambered heart and one circle of blood circulation. In further development, lungs, a three-chambered heart, and two circles of blood circulation appear. Next come the hind and forelimbs. First, it becomes thinner, and then shortened, then the tail disappears completely, and the tadpole turns into a small frog. This process lasts 3-4 months and is called metamorphosis. Sexual maturity in frogs occurs in the third year of life.

Seasonal natural phenomena affect the life cycle of amphibians. So, due to the conditions of seasonal climatic changes, their annual cycle is divided into such periods: spring awakening, spawning period(breeding), summer activity period and hibernation, hibernation can be terrestrial (newts) and underwater (frogs).

Amphibians , or amphibians, are very different from all vertebrates. In life, they need to distinguish between two periods: in their youth they are similar to fish, and then gradually turn into animals with pulmonary respiration. Thus, in the cycle of development of amphibians, a transformation takes place, which is almost never found in other vertebrates, and, on the contrary, is widespread in lower, invertebrate animals.

general characteristics

In terms of lifestyle and appearance, amphibians are very similar, on the one hand, to reptiles, and on the other, even more so to fish; their larval stage constitutes, as it were, the transition between these two orders.

The shape of the body is very different. Tailed amphibians are more similar to fish, have a laterally compressed body and a long paddle-shaped tail; in others, the body is rounded or flat, and the tail is completely absent. Some amphibians have no limbs at all, in others they are very poorly developed, in others, on the contrary, they are strongly developed.

Device skeleton amphibians are to some extent similar to fish. In fish-like amphibians, the vertebrae are exactly the same as in fish; in others, vertebrae develop with an articular head in front and a dimple in the back, which results in complete articulation. The transverse processes of the vertebrae are well developed in all amphibians, but true ribs usually do not develop; instead of them there are only small bone or cartilaginous appendages. The aforementioned transverse processes are very long in some and replace the missing ribs.

Device skulls is varied; here you can notice the gradual complication and increase in bone formations due to cartilage and connective tissue. A characteristic feature of the entire class of amphibians are two articular heads on the occipital part of the skull, which correspond to two dimples of the first cervical vertebra. The skull is always flat, wide, the eye sockets are very large. The cranium consists of two occipital bones, two frontal bones, the main bone. In the lateral walls of the skull, for the most part, ossification does not occur at all, or the cartilage ossifies partly. The palatine bones are fixedly connected to the skull; on them, just like on the vomer and on the wedge, teeth sometimes sit. The lower jaw consists of two or more parts and never fully ossifies.

Brain amphibian has a simple device. It has an elongated shape and consists of two anterior hemispheres, the midbrain and cerebellum, representing only the transverse bridge, and oblong. The spinal cord is much more developed than the brain.

From feelings improved vision, hearing and sense of smell. The tongue of most amphibians is well developed, and in frogs it differs significantly from the tongue of other vertebrates in that it is attached not at the rear, but at the front end and can be thrown out of the mouth.

The teeth, like those of reptiles, are adapted only for grasping and holding prey, but cannot serve to chew it.

alimentary canal comparatively short and simply arranged; it consists of a long esophagus, a simple thick-walled stomach, and a hindgut. All amphibians have a lobed liver, gallbladder, pancreas, kidneys, and bladder.

Circulatory and respiratory organs are of great importance in the life of amphibians and will be discussed further in connection with the history of development.

Feature of amphibians consists in the absence of any hard outer covers, which is why they are called naked reptiles. Indeed, they have neither scales, like fish and reptiles, nor feathers, nor wool, like mammals; most are covered on the outside only with bare skin, and only a very few have some traces or semblance of horn formations on the skin. But in the skin of amphibians there are some formations that other vertebrates do not have.

In the connective tissue layer of the skin, some amphibians have small capsules filled with a gelatinous substance; in others, voluminous cavities are formed, adapted for the development and initial storage of embryos. Finally, in some, ossifications or hard plates sometimes appear in the skin, somewhat similar to fish scales. The top layer of the skin is very thin and often contains various dyes.

However, the color of some amphibians can change, as we have seen in chameleons, and is determined in most cases by the mutual arrangement and condition of the special pigments of the cells contained in the skin. Compression or expansion, change in shape, approaching the outer surface of the skin or moving away from it - everything gives this or that color to the skin and is caused both by a change in external conditions and by internal irritation.

Both in the upper layer of the skin and in the inner layer of all amphibians there are a lot of glands of various sizes and for various purposes. The most interesting of these are poisonous glands. They are located in the lower layer of the skin, have a spherical or oval shape, separate the mucous liquid in which the toxic substance is located. Amphibians, in which such glands are more developed, can voluntarily increase the secretion of these glands and use it as a means of protection. It has now been established that the poisons of some amphibians are very strong, but they are not dangerous for humans and large animals because they are contained in the mucus only in a very small impurity. However, experiments show that this poison can be fatal for many animals. Injecting toad venom into the blood of small birds quickly kills them; in the same way, the poisonous mucus of toads, introduced into the blood of puppies, guinea pigs, frogs and newts, acts deadly. Some toads, especially salamanders, have very developed mucous glands, from which they can produce a very copious secretion at will, even squirt drops of a poisonous liquid; hence the popular belief that the salamander does not burn in fire.

In most amphibians, the initial development of embryos occurs in the same way as in fish. Eggs are usually laid in the water in the form of eggs, which are fertilized later, already in the water. Eggs are surrounded by a thick layer of gelatinous substance. This shell is of great importance for the embryo, since in this way the egg is protected from drying out, from mechanical damage, and most importantly, it protects them from being eaten by other animals; indeed, very few birds are able to swallow a gelatinous lump of frog roe; the shell itself also protects the eggs from attack by fish, mollusks and aquatic insects.

After the embryo completes the initial stages of its development, the larva breaks through the gelatinous membrane, feeding on it, and begins to lead an independent life in the water. The larva has a flat flattened head, a rounded body and a long oar-like tail, trimmed above and below with a leathery fin. On the head, the original external gills grow in the form of tree-like branched processes. After some time, these gills fall off and internal gills form in their place. The body gradually narrows even more, the caudal fin increases, and little by little the limbs begin to develop; in frog tadpoles, the hind limbs grow first, and then the forelimbs, while in salamanders, on the contrary. Tadpoles feed primarily on plant foods at first, but gradually more and more switch to animal food. At the same time, changes take place in the organization of the whole body: the tail, which at first is the only organ of movement, loses its significance and shortens as the limbs develop; the intestines become shorter and adapt to the digestion of animal food; the horny plates with which the jaws of the tadpole are armed are sharpened, gradually disappear and are replaced by real teeth. The ever-shortening tail finally completely disappears - and the tadpole turns into an adult frog.

In the development of the brain and sense organs of amphibians, there is a great similarity with fish. The heart is formed in larvae very early and immediately begins to act. Initially, it is a simple bag, which is subsequently divided into separate parts. The aorta passes into the gill arches and branches first in the external gills, and later in the internal ones. The blood flows back through the vein running along the tail, and then branches on the surface of the yolk sac and returns through the yolk veins back to the atrium. Later, the portal systems of the liver and kidneys are gradually formed. At the end of the larval stage, gill respiration is gradually replaced by pulmonary respiration; the anterior branchial arches turn into the head arteries, and the middle ones form the aorta.

Amphibians live in all parts of the world and in all zones, with the exception of the polar countries. Water even more than heat is a necessary condition for their existence, so almost all amphibians spend their larval stages in water. They live exclusively in fresh waters, avoiding moscoes or generally salt water. Almost half of the amphibians spend their entire lives in the water, while others in adulthood settle on land, although they always stay close to water and in damp places; there are no completely dry amphibians in areas, but they can live where, with general dryness, it rains regularly at certain times. The dry season in such places is spent in hibernation, buried deep in the silt, in the temperate zone they are just as susceptible to hibernation. Tropical countries, abundant in forests and water, are the most favorable for their life. Such are the central parts of South America, Madagascar, the islands of the Malay archipelago, where virgin, moist forests grow in abundance; on the contrary, Central Asia, Australia and most of inner Africa are very poor in amphibians. All amphibians swim perfectly in the water, not only in the larval state, but also in the adult state, on land the tailed ones crawl like reptiles, and the tailless ones move in short heavy jumps; many of them can even climb trees.

In contrast to reptiles, amphibians are almost all vociferous; many of them can even be called songbirds, although their voice is far from being as pleasant as that of birds. However, only adult males can scream and sing, and not females, as well as all young amphibians, can be called dumb. Mental abilities in amphibians are no more developed than in reptiles. According to some researchers, in general they should be ranked among the most stupid of all vertebrates.

Everything that has been said about reptiles regarding their insignificant degree of vital activity is quite applicable to amphibians, which also have cold blood. Their social life is just as little developed; however, their concern for offspring is somewhat more noticeable than that of reptiles.

Most amphibians are nocturnal, from sunset to morning. During the day, many of them crawl somewhere into cracks or under stones and sit motionless, others enjoy the warmth of the sun and spend the day half asleep.

The food of amphibians varies with age. The larvae eat all sorts of small organisms, both plant and animal: ciliates, rotifers, microscopic crustaceans and small algae; as they transform, they have more and more need for living food. Adult amphibians are already real predators and pursue all animals that they can overpower, starting with worms and insects and ending with small vertebrates; they even eat the larvae of their own species if they are able to swallow them. Most of them are characterized by great voracity, which increases with increasing ambient temperature; so, in spring, frogs eat less than in summer, although they wake up after hibernation very thin; in the same way, tropical species are more voracious than the inhabitants of temperate countries.

At the beginning of their life they grow very quickly, but over time their growth slows down greatly. Frogs become mature only at 4 - 5 years of age, but continue to grow for another 10 years; others reach their real size only at the age of 30.

Starvation amphibians are able to endure no less than reptiles; a toad planted in a damp place can go without food for more than two years.

In the same way, amphibians also have the ability to restore lost parts (regeneration): a broken tail, a cut off finger, and even a whole leg grow back; however, this ability in more highly organized forms is noticeably reduced and even completely disappears. Their wounds heal just as easily as those of reptiles. In general, the survivability of some amphibians is amazing, especially tailed amphibians are distinguished by this quality. A salamander or a newt can be completely frozen in water; in this state they become brittle and show absolutely no signs of life; but only the ice will melt; these animals wake up again and, as if nothing had happened, continue to live. Taken out of the water and placed in a dry place, the newt shrinks and is a completely lifeless mass. But as soon as this dead lump is thrown into the water, a living newt is again obtained in complete well-being.

According to their appearance and degree of organization, amphibians are divided into three orders: tailless, tailed and legless.

Class amphibians or amphibians - the first terrestrial vertebrates. They cannot be considered completely terrestrial animals because in them (with rare exceptions) the development of the larva occurs in the aquatic environment.

The structure of the lungs and the mechanism of their ventilation in amphibians is insufficient to ensure the absorption of the required amount of oxygen. In this regard, part of the respiratory function is taken over by the skin, which prevents the development of strong integuments that did not allow evaporation, and makes it impossible to completely separate arterial and venous blood.

On the surface of the epidermis, many glands open, producing mucus, which protects the skin from drying out. The integuments of amphibians are permeable to water.

The following sections are distinguished in the amphibian spine: cervical (one vertebra), trunk (from seven to one hundred), sacral (one), caudal (up to one hundred). The cervical vertebra provides limited mobility of the head. With the trunk vertebrae of caudate amphibians (for example, newts) articulating short ribs, which, however, are not connected with the sternum, so that the chest is absent in all amphibians. The sacral vertebra serves as a support for the hind limbs. In tailless amphibians (toads, frogs), all caudal vertebrae fuse. The superior arches of all vertebrae form the spinal canal. The chord is reduced in most cases. In the skull there is a tendency for the bones to coalesce and their number to decrease. The girdle of the forelimbs (coracoid, clavicle and scapula) lies in the thickness of the musculature and is not attached to either the skull or the spine. The pelvic girdle (iliac and gluteal bones, pubic cartilage) is connected to the sacral vertebrae. The forelimbs are represented by the shoulder (consists of the humerus), the forearm (consists of the ulna and radius bones, which in anurans often grow together), the hand (the bones of the wrist, metacarpus and phalanx of the fingers). The hind limbs are represented by the femur (consists of the femur), lower leg (consists of the tibia and fibula, which can also grow together), foot (tarsal bones, metatarsus, phalanxes of the fingers). The segmental structure of the muscles is preserved to some extent only in the trunk region. The muscles of the extremities, due to their strong differentiation, lose their metamerism. The forebrain consists of two hemispheres covered by the primary cortex. There are two thickenings in the spinal cord, corresponding to the fore and hind limbs. The eyesight of amphibians is not very good, which is associated with the transition to a new habitat. There are movable eyelids that protect the eyes from dust. The middle ear cavity appears, separated from the external environment by the tympanic membrane. Lateral line organs are present only in larvae and some anurans that have returned to an aquatic lifestyle. Adult amphibians feed on small invertebrates, which are captured in many cases with the help of a long tongue. Teeth may be involved in the capture of prey (they are absent in frogs). The ducts of the salivary glands open into the oropharyngeal cavity. Their secret wets food, but does not contain digestive enzymes. Food enters the short esophagus, then the stomach, small and large intestines. The rectum opens into the cloaca. The liver and pancreas are well developed. The lungs of amphibians have a cellular structure. Since there is no chest, breathing is carried out by the work of the oropharyngeal pump: air passes through the choanae into the oral cavity, and is pumped into the lungs by contractions of the muscles of the pharynx. In most amphibians, skin respiration plays an important role.

The heart is three-chambered, consists of two atria and a ventricle. The left atrium receives arterial blood from the lungs (through the pulmonary veins), and the right atrium receives venous blood from the whole body, mixed with arterial blood from the vessels of the skin. In the ventricle, arterial and venous blood are partially mixed, however, thanks to a special mechanism, the chairman receives oxygenated blood, other organs receive mixed blood, and venous blood enters the lungs through the pulmonary arteries.

The excretion of metabolic products (urea) is carried out by the trunk kidneys. Through the ureters, urine enters the bladder, where there is a partial absorption of water, and then into the cloaca.

The male reproductive organs (testes) open into the cloaca through the urogenital opening, and the female (ovaries) through the oviducts. Fertilization in most anurans is external, while in caudate and legless, internal fertilization predominates. Larvae (tadpoles) emerging from eggs of anurans have gills, a tail as an organ of movement and a lateral line as an additional respiratory organ - signs characteristic of fish. Then metamorphosis occurs, and the tadpole turns into a small frog. In other amphibians, metamorphosis can occur right in the egg. In the majority of the legless, a live birth is observed. Many species take care of their offspring. The green lake frog is quite large - up to 15 cm. The color is predominantly green, sometimes quite dark, brownish-brown.

The pond frog is smaller than the lake frog. These frogs live near bodies of water, although they can sit on land for hours. They are cautious enough, having heard a rustle, they fall into the water with one jump. In the water, they sink to the bottom, burrow into the mud, so it is difficult to catch them. They feed on insects, their aquatic larvae, and fish fry. Frogs are voracious, they rush to everything small that moves in the water, even to a fishing rod or lure. Demanding heat, they leave early for wintering (burrow into the mud at the bottom), appear later than other species in the spring, lay eggs when the water is already warm enough: in the second half of May, even in June. The appearance of frogs is evidenced by their croaking. In a croaking male, resonators are inflated on the sides of the head - large bubbles that amplify the sound. Poidayuchp insects, frogs destroy many pests, so they are considered useful animals. But in a fish farm, they eat fish fry, which causes some harm. In Western Europe and America, green frogs are eaten.

All over the globe. They are not found only in Antarctica, Australia and the Sahara.

frogs have a wide, but small body, round bulging eyes, well-developed limbs.

The hind legs are longer than the front. But it's not surprising how she jumps, everyone knows.

The color scheme of the color of these amphibians is in green tones. Some people have light skin, some darker.

Some species have a pattern on the body. Frogs breathe through their skin and lungs. With the help of a long sticky tongue, the frog gets its own food.

The frog feeds on terrestrial invertebrates. Its menu includes: caterpillars, beetles, spiders, flying insects, centipedes and others like them. The wah's eyesight is not very good, it sees only moving objects.

When danger threatens, he cannot always understand, so he becomes an easy prey. And she has many enemies. These are snakes, birds and fish. The man also put his hand, it turns out to be delicious. But not all of them can be eaten. They live both on land and in water.

Frogs breed in water bodies. During the mating season, males can also fight among themselves, kicking each other with their hind legs.

Much better competitive singing. Females meticulously listen to the performers and evaluate their vocal abilities. They spawn, from which tadpoles hatch.

Tadpoles have a tail and gills, they need all this for the period of living in the water. Tadpoles feed on aquatic plants, fly larvae and mosquitoes.

After some time, the gills and tail die off, paws grow, and you can get out on land.

In countries where there is a cold climate, frogs hibernate. They winter at the bottom of reservoirs in thickets of vegetation. And some settle down to sleep in stumps, holes, or burrow into foliage. In hibernation, she takes the following position: she covers her head with her front paws, and presses her hind legs. During the cold period, their sleep lasts from 180 to 230 days.

In nature, frogs live up to 18 years.

The most common types of frogs:

Frogs are animals from the order of tailless amphibians, or amphibians. They are found all over the globe, except for deserts and cold regions - Greenland, Taimyr, the Arctic and Antarctica. The main thing that is necessary for their life - freshwater reservoirs, and in adulthood - the ability to be on land. They move on land by jumping, but some can walk and run, as well as dig underground holes. They swim well in the water. Tree frogs can climb trees.

frog species

The detachment of tailless amphibians is very numerous - over 2000 species. Scientists divide the detachment into families:

• real frogs (about 600 species);
• real toads (more than 500 species);
• tree frogs (more than 900 species).

toads characterized by the absence of teeth and bumpy skin, and tree frogs- the presence of suction discs on the fingers, with the help of which they easily climb a tree along smooth trunks and leaves.

Most species of the family of real frogs live in Africa - the supposed homeland of these animals, other regions with a humid tropical and subtropical climate. It is impossible to list all the species in this message, so let's call the most common species in Russia:

• herbal;
• pond;
• moor;
• lake;
• Siberian;
• Asia Minor.

The largest of them are lakes. Their length can reach 15 cm. The males of this species are famous for their loud croaking.

Appearance and body structure

The sizes of frogs are very different - from 8 mm to 32 cm. Skin color also varies. It can be green, brown, brown, red, blue, yellow, spotted, striped. It depends on the air temperature, lighting, humidity, emotional state of the amphibian. Besides, skin color helps to camouflage. Tree frogs have a very bright color.

The structure of the body has a number of features:

• short torso and neck;
• absence of a tail;
• short forelimbs and long hind limbs;
• swimming membranes on the hind limbs;
• toothless lower jaw;
• long riveting tongue.

The eyes of frogs are unique - they are pushed forward and can simultaneously see what is happening in front, above and to the side. The eyes protect the eyelids: the upper one is leathery, the lower one is transparent. Behind each eye is a tympanic membrane. There is no external ear.

Breathe easy. Breathing under water is carried out with the help of the skin. The fact is that the skin of these amphibians passes water, and oxygen passes from the water through the skin directly into the blood. This allows you to stay under water for a long time. The lungs are used not only for breathing - with their help, air is passed from the larynx and a loud croaking is heard.

Life cycles

croaking It's a way to attract a female. Frogs reproduce by laying eggs in water. Then tadpoles emerge from the eggs. tadpoles are larvae that live only in water. They have a tail, a cartilaginous skeleton, and gills. They feed on algae. During the process of metamorphosis, which lasts about a day, the tadpole turns into an adult.

Adults feed on beetles, spiders, caterpillars, worms, and snails. Some large species are caught,. Most often They hunt with a long, sticky tongue.

In cold regions, amphibians hibernate for the winter. They climb into rodent burrows, hide in dry foliage, and lie on the bottom of reservoirs. Hibernation lasts several months and ends by March-April.

On average, these amphibians live for about 10 years, but representatives of some species can live over 30 years.

The most amazing frogs

1. Brazilian horned. Its color is similar to leaves. The size reaches 20 cm. Some people keep them as pets.
2. Purple. Lives in southern India. It has a purple color, lives underground. The nose is like a pig's snout.
3. Suriname Pipa. Its main feature is a very flat body and small eyes.
4. Glass. On the lower part of the body such transparent skin that you can see the insides.
5. goliath frog- the largest in the world. The size can reach 32cm and the weight is 3kg.

The image of a frog in culture

The attitude towards these amphibians is different. Many consider them unattractive and dangerous, but some are happy to keep them at home.

Since ancient times, frogs have acted as mythological and literary characters:

• in Egyptian mythology, the frog goddess Hekat is a symbol of fertility;
• in Aristophanes' comedy "The Frogs";
• in the Russian fairy tale "The Frog Princess";
• in the cartoons "Shrek 2" and "Shrek the Third";
• Kermit the Frog on Sesame Street.

Unfortunately, The number of frogs in the world is rapidly declining. This is due to habitat destruction, the use of chemicals, climate change.

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