General remarks

Experiments have found that a frog weighing 31 g at a temperature of + 20° absorbs 105 cm 3 of oxygen per hour per kilogram of live weight in winter, and in spring (April) 211 cm 3 of oxygen. On average, one green frog consumes 0.2259 g of oxygen per day and releases 0.0677 g of carbon dioxide. At night, the release of carbon dioxide increases.

Taking the weight of oxygen consumed at +2° or +3° and carbon dioxide released at the same temperature as 100%, we obtain the following changes in connection with temperature (on 6 frogs in 6 hours):

The respiratory quotient (the amount of carbon dioxide produced divided by the amount of oxygen consumed) of a frog varies depending on the partial pressure of oxygen in environment in the following way:

Respiratory coefficient......... 2.4 1.02 0.90 0.83 0.73

The affinity of frog hemoglobin for oxygen is lower than that of humans. It follows that when equal temperature Human blood takes up more oxygen than frog blood. However, at the low temperature characteristic of the frog’s body, its hemoglobin is able to bind the same amount of oxygen as a person binds at normal temperature his body. Compared to mammals, the bullfrog's blood binds relatively large quantities carbon dioxide, but cannot regulate its alkalinity. The oxygen capacity of the green frog's blood is 13.5-23 percent by volume. The grass frog consumes more oxygen than the green frog.

Oxygen at a pressure of 3.5 atmospheres kills a frog within 65 hours. Frogs can exist for many hours in a nitrogen atmosphere. If all the blood of a frog is replaced with a 0.8% solution of table salt, then it takes several hours for the cells of the central nervous system They completely lost their irritability.

As already indicated, in frogs skin respiration is of exceptional importance. Unlike mammals, amphibians have a larger skin surface area than their lungs. (in amphibians the ratio of these surfaces is 3:2, in mammals - 1: 50-100, in humans 1: 55-70). Through the skin, the frog gives off more carbon dioxide (respiratory coefficient 1.9-2.5) than it receives oxygen, and through the lungs - vice versa (respiratory coefficient 0.3-0.4). The oral mucosa is of some importance in gas exchange. As the temperature rises, skin respiration becomes insufficient. Experiments have shown that under water (without air) frogs survive the following periods:

Body temperature......2° 6° 11.8° 13.8° 15.5° 18.5° 21.1° 26.5° 29°

Survival in hours... 192.3 29.2 8.0 4.5 3.0 2.3 1.7 0.8 0.2

From this it is clear that when high temperatures pulmonary breathing comes first. Only the pulmonary respiration apparatus will be considered below.

Respiratory tract

From the oral cavity, described briefly in Chapter I and in more detail in Chapter IX, the azygos respiratory tract (pars larungo-trachealis) begins. It is a hollow organ, covered from the inside by a continuation of the mucous membrane of the oral cavity, strengthened (especially in its anterior part) by the skeleton of the larynx and equipped with muscles. The usual division into the larynx (larynx) and windpipe (trachea) in the frog is practically not applicable. On the laryngeal eminence (prominentia laryngea) there is a longitudinal respiratory fissure (aditus laryngis), closed in the interval between inhalation and exhalation. Having passed through the respiratory slit, the air enters the vestibule of the larynx (vestibulum laryngis), separated by the vocal cords (labia vocalia) from the laryngeal-tracheal cavity (cavum laryngo-tracheale). The latter is a homologue of the trachea of ​​other forms. The way forward goes through the right and left pulmonary opening (aditus pulmonis) into the lungs.

Rice. 1. Cartilaginous skeleton of the larynx of a green frog from above (a) and from the side (6).

On the first, the terminal cartilages are removed:

1 - apical notch, 2 - mid-posterior process, 3 - tracheal process, 4 - body of the hyoid apparatus, 5 - posterolateral process, 6 - anterior articular process of the cricoid-tracheal cartilage, 7 - cricoid part, 8 - muscular process, 9 - posterior articular process, 10 - hyoid cricoid ligament, 11 - pulmonary process, 12 - esophageal spine, 13 - posterior terminal convexity, 14 - terminal cartilage, 15 - anterior terminal convexity, 16 - arytenoid cartilage, 17 - anterior vocal cushion , 18 - posterior vocal cushion, 19 - trailing process.

The skeleton of the frog's respiratory tract consists of three large and four small cartilaginous formations: an unpaired cricoid trachealis (cartilago cricotrachealis), two arytenoids (cartilagines arytaenoideae), two terminal (cartilagines apicales) and two main (cartilagines basales) cartilages. The cricoid cartilage consists of a cartilaginous ring called the cricoid part (pars cricoidea = annulus) and a posterior tracheal part (pars trachealis). The cricoid part occupies an inclined position relative to the horizon in a normally sitting animal. At the posterior end of the cricoid part there is an unpaired spine of the esophagus (spina oesophagea), adjacent to the abdominal part of the latter. On each side of the cricoid part there is an anterior articular (processus articularis anterior), muscular (pr. muscularis) and posterior articular (pr. art. posterior) process. On the outer surface of the latter, the hyoid-cricoid (ligamentum hyo-cricoideum) and intercricoid (Iig. intercricoideum) ligaments are attached. The tracheal part consists of two (right and left) thin curved strips of cartilage, connected in the back of the green frog by a transverse crossbar (absent in the grass frog). The thin lateral part is called the tracheal process (processus trachealis = pr. bronchialis). At its connection with the transverse crossbar, the pulmonary process (pr. pulmonalis) extends back, and from the middle of the crossbar the unpaired trailing one (pr. obturatorius) goes forward. The cricoid cartilage serves as a frame to which the arytenoid cartilages are attached. The latter are thin curved triangular plates that limit the respiratory gap on the right and left. In their lower part there is a thick vocal pad (pulvinaria vocalia), movably connected by connective tissue. At the apex of each arytenoid cartilage there is a small apical notch (incisura apicalis), in front of which lies the anterior (prominentia apicalis anterior), and behind it lies the posterior (prom. apicalis posterior) apical convexities. The notch itself is occupied by the movable apical cartilage. The main cartilage is placed in the middle of the arytenoid cartilage, being hidden in the transverse mucous fold.

Rice. 2. Musculature of the green frog's larynx from above. On the left, the superficial part of the laryngeal dilator has been removed so that its deep parts are visible:

1 - hypoglossal-laryngeal muscle, 2 - cricoid-cricoid part of the laryngeal dilator, 3 - hyoid-cricoid part of the laryngeal dilator, 4 - hyoglossus muscle, 5 - posterior constrictor, 6 - hyoid-cricoid ligament, 7 - pleural border, 8 - body of the hyoid apparatus, 9-11 - first, agora and third posterior masticatory muscles, 12 - superficial part of the laryngeal dilator, 13 - anterior compressor, 14 - intercricoid ligament, 13 - dorsal branch of the pulmonary artery, 16 - esophageal spine.

The muscles of the larynx close and open the airway. There are 4 muscles on each side, of which one, the laryngeal dilator (musculus dilatator laryngis), opens the lumen, and the other three are the sublingual laryngeal (m. hyo-laryngeus), anterior (m. sphincter anterior) and posterior (m. sph. posterior) compressors - act in the opposite direction. The laryngeal dilator consists of a superficial part and a deeper part, which in turn is divided into two.

The superficial part extends from the cartilaginous end of the mid-posterior process of the hyoid apparatus and is attached to the upper part of the arytenoid cartilage, with some of its fibers reaching the apical cartilage.

The deep part of the laryngeal dilator is divided by the muscular process of the cricoid cartilage into two parts - the cricoid-arytenoid (pars crico-arytaenoidea) and the sublingual cricoid (pars hyo-cricoidea). The hypoglossal laryngeal muscle starts from the dorsal surface of the bony part of the mid-posterior process of the hyoid apparatus and connects in front of the respiratory fissure with its partner on the other side. The constrictor anterior muscle lies under other muscles on the side of the arytenoid cartilage. The posterior constrictor is divided into two parts, having a common attachment at both ends. The posterior attachment point is the outer part of the posterior ends of the arytenoid cartilages, and the anterior attachment is that on the anterior ends of the same cartilages. The middle part of the muscle remains undivided, and the lateral (weaker) part has a tendon in its middle part. All the described muscles of the larynx are supplied by branches of the long laryngeal nerve, and the dilator of the larynx receives another branch from the short laryngeal nerve.

As already mentioned, the vocal cords are located between the vestibule of the larynx and the laryngeal-tracheal cavity.

Rice. 3. Deep layer of green frog laryngeal musculature from above:

1 - hyoid-laryngeal muscle (cut), 2 - hyoid-cricoid part of the laryngeal dilator, 3 - posterior compressor, 4 - hyoid-cricoid ligament, 5-anterior compressor, 6 - intermediate tendon of the posterior compressor of the larynx, 7 - cricoid-arytenoid part laryngeal dilator, 8 - posterior constrictor, 9 - intercricoid ligament.

The gap between these two cavities is called the glottis (rima glotti dis). The vocal cord on each side is divided by a longitudinal groove (sulcus longitudinalis) into an upper (pars superior) and lower (pars inferior) part. The pulmonary opening is almost completely surrounded by a fold of the mucous membrane - the bronchial fold (plica bronchialis).

Rice. 4. Longitudinal section through the respiratory tract of a green frog associated with the left lung:

1 - vestibule of the larynx, 2 - intercricoid ligament, 3 - posterior vocal cushion, 4 - cricoid-tracheal cartilage, 5 - pleural border, 6 - left lung, 7 - body of the hyoid apparatus, 8 - lingohyoid muscle, 9 - hyoid - laryngeal muscle, 10 - anterior vocal cushion, 11 - lower part of the vocal ligament, 12 - cricoid-tracheal cartilage, 13 - laryngeal-tracheal cavity, 14 - bronchial fold, 15 - pulmonary opening, 16 - cricoid-tracheal cartilage, 17 - pulmonary vein.

The respiratory tract is covered with ciliated epithelium with mucous glands. There is no ciliated epithelium on the vocal cords.

Lungs

The lungs (pulmones) are two wide, symmetrical, freely spaced thin-walled sacs. At the base they are somewhat narrowed (“root” of the lung); the posterior end of the lung becomes slightly sharper. If the lung is inflated, it becomes almost round. The length of the inflated lung is different types frogs from 29 to 47% of body length. There is a significant cavity inside the lung, and on the walls there are a number of chambers separated from each other by partitions (sertae). From the outside, these partitions give the lung the appearance of foam, and from the inside you can see that the cells (“alveoli”) of the first order break up into cells of the second and sometimes third order. There are from 30 to 40 cells of the first order. Cells of the second order are generally 4 times larger.

The peritoneum, lining the body cavity, wraps around each lung, covering it with a thin, smooth membrane - the pleura.

Due to the filling of numerous capillaries with blood, the lungs in a fresh state appear light pink.

Lymphatic vessels usually follow the course of the blood vessels. Numerous thin nerve fibers of the lungs originate from the vagus nerve. Histologically, lung tissue consists of smooth muscle fibers and fibrous connective tissue. In some places there are thin elastic fibers and, somewhat more often, star-shaped black pigment cells. The inner surface of the lung is covered with a single-layer epithelium, which, in those places where it covers the first-order septa, bears ciliated cilia.

Breathing mechanism

We should not forget that in a frog the lungs play the role of a hydrostatic apparatus: a frog with its lungs removed cannot swim on the surface, and if the lungs are artificially inflated, then the frog is unable to dive. The respiratory movements of modern anurans arose by transforming the process of larvae drawing water through the mouth to wash the gills, and later for gas exchange through the oral mucosa.

The absence of ribs makes it impossible for the frog to inhale air using the suction pump method. Its oral cavity functions as a pressure pump, and therefore the frog's mouth must remain closed: a frog with its mouth open must suffocate. Observing a living frog, it is easy to notice two types of oscillatory movements of the throat alternating with each other: constant small oscillations (“oscillating”) and more rare but stronger ones. With vibrations of the first kind, the respiratory gap remains closed and the entire effect is reduced to refreshing the air in the oral cavity with air drawn in through the nostrils. This mechanism ensures breathing through the oral mucosa. Strong oscillatory movements of the skin of the throat are associated with pulmonary breathing. They can be distinguished into three phases: retraction (“aspiration”), exhalation (“expiration”) and inhalation (“inspiration”). In the first phase, air is sucked in by pulling the lower wall into the oral cavity through the nostrils with the respiratory slit closed. Then the latter opens, and air from the lungs, mainly by contraction of the abdominal muscles, is pushed into the oral cavity (second phase). Immediately after this, with the nostrils tightly closed, the bottom of the oral cavity is pulled up and the mixed air from it is pushed (“swallowed”) into the lungs (third phase). From what has been said, it is clear how important the mechanism of closing the nostrils is for the frog. The smooth muscles of the nasal apparatus are insufficient for this purpose. It has been noted that pressing the prelingual tubercle of the mandible on the premaxillary bones moves the latter so that the ascending process of the facial part of each premaxillary bone helps to close the nostril closest to it. In addition, when the floor of the oral cavity is strongly pulled up, the anterior processes of the hyoid apparatus clamp the choanae.

Rice. 5. The interior of a severely inflated left lung.

Under natural conditions, young frogs breathe somewhat more frequently than adults. Data processing by Bannikov (1940) gives for young people grass frogs from near Moscow, this dependence of the number of respiratory movements per minute (P) on air temperature (t°): p = 43.62 + 7.52 A similar relationship for adult frogs can be expressed by the formula: p = 19.9 + 7.55t °. In addition to temperature, the respiratory rhythm is also influenced by all sorts of sudden changes: a sharp change in lighting, the appearance of moving objects in the field of view, mechanical irritations, etc. The frog reacts to all such phenomena by increasing the respiratory rhythm, but then it returns to its previous state.

From internal factors special meaning has carbon dioxide content in the blood: the passage of fluid rich in carbon dioxide; through the isolated head of the frog gives a noticeable increase in the respiratory rhythm.

Endocrine glands

It is worth mentioning two glands, both topographically and ontogenetically related to the respiratory organs.

The thyroid gland (glandula thyreoidea) is paired and lies in the form of a poorly visible oblong-oval or round body between the posterolateral and mid-posterior processes of the hyoid apparatus. Its relationship to the surrounding cartilage and muscles is variable. Often it only adjoins the edge of the hyoglossus muscle, but sometimes it is completely covered by it on the ventral side.

Rice. 6. Secondary mechanism for closing the green frog's nostrils. A projection of the hyoid apparatus and the cartilaginous part of the presternum is given on the roof of the oral cavity.

Rice. 7. Position of the green frog thyroid gland:

1 - main horn of the hyoid apparatus, 2 - thyroid gland, 3 - vocal sac.

Blood circulation in the gland is supplied by branches of the external carotid artery and external jugular vein. The thyroid gland contains iodine (in Ram piriens 0.063%), which is apparently the main active principle her hormone. The latter enhances metabolism, increases pulse and excitability. Thyroid hormone plays an essential role in the process of metamorphosis.

The thymus gland (gl. thymus) of the frog is also steamy. It lies in the form of a small oblong oval body at the back eardrum, under the muscle that pulls the lower jaw down. In a green frog 8 cm long, the thymus gland measures 3x1.5 mm. This gland is best expressed in young frogs, and with age it experiences increasing degeneration. Its significance has been studied primarily in higher vertebrates, where it regulates the rate of development. In frogs, the thymus gland produces white blood cells. Removal of the thymus gland causes a number of disorders in frogs: weakening of muscles, skin ulcers, swelling, bleeding, etc. Feeding tadpoles with the thyroid gland enhances the development of thymus.

Rice. 8. Position of the thymus gland:

1 - vein of the thymus gland, 2 - thymus gland, 3 - ring of the tympanic membrane, 4 - dorsal muscle of the scapula, 5 - lateral branch of the large cutaneous artery, 6 - deltoid muscle, 7 - depressor mandible, 8 - small masticatory muscle.

Literature used: P. V. Terentyev
Frog: Tutorial/ P.V. Terentyev;
edited by M. A. Vorontsova, A. I. Proyaeva. - M. 1950

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Toads and frogs, many want to know how these amphibians differ and whether there is at least some difference between them. People confuse them because they are similar in appearance, are amphibious, and are not very pleasant to look at. In fact, the difference is very big. They have their own characteristics by which they can be distinguished. How can they differ?

How is a frog different from a toad?

More about frogs

The frog is an animal of the order Anura, which inhabits almost all countries. Lives up to fifteen years. This tailless creature loves a bright, nice, sunny day more than a dark evening. Why hunt for insects at night when you can hunt during the day and relax at night and in the evening. In an individual long legs, which are designed for jumping. She is quite timid; when she sees a threat, she immediately runs away at the first opportunity. To get to your food, you just need to pull out long tongue and guess the moment when to eat. The frog has its own uniqueness, it can breathe through skin. Despite the fact that her body is small, her head is large and she is always in an elevated position.

The color of an animal consists of a combination of colors

• yellow
• green
• red

Caviar looks like small round lumps, wrapped in a mucous layer. An individual always begins its frog life in water. From the eggs that she laid in the water, a small tadpole develops, and when it is born, it is very similar to a fry. For example, an amphibian bovine species, individuals of which are capable of laying more than twenty thousand eggs, from which tadpoles emerge. Only when the little frog becomes more like an adult frog does it come out onto land.

Frogs never do not go far from bodies of water. Tailless babies move in different ways. In the environment natural habitat These animals can jump, swim and dig holes. The skin of these amphibians is bare and covered with mucus, so the activity of this animal is highly dependent on humidity and air temperature.

Who are toads

The toad is a large amphibian animal. They can live more than thirty-nine years. In various fairy tales, this nasty animal is a bad symbol and is often associated with a freak character. The main injustice is that people are compared to this disgusting creature. And if you remember how much benefit this unfortunate creature brings, then you really feel sorry for the animal. Toads have a rather dense build. Scattered on the skin poison glands. The parotid glands are located behind the eyes; they are safe for humans as they do not secrete poison.

When she sees a person, she remains in place thanks to her skin, which protects her. A toad, of course, is different from a frog, it is larger, but the head of this person is smaller than that of a small frog. Another difference between the toad is that it cannot jump deftly and moves very slowly.

Toad goes out hunting in the evening hiding in the grass and looking for tasty insects. After all, she doesn’t like the heat of the day. She has short tongue, so she will have to get close enough to the food and somehow push it into her mouth. It is much more difficult for an individual to eat an insect, because it has to make slow movements to catch food. And if the insect flies away, the toad will have to chase it while it is in its field of vision.

The individual does not have chest, that is, if you touch behind the front paws, you can find a special softness.

They lay out their eggs in the form of small ropes. The eggs are found at the bottom of reservoirs or shrouded in underwater plants. Their tadpoles are also at the bottom, as are their eggs. When the tadpoles have already grown up, they come to land and enter only when they need to lay eggs. In one year a toad can lay out ten thousand eggs.

Its color is dull and dull, making it almost impossible to find at night.

Differences between a toad and a frog

Even our ancestors knew the difference between a toad and a frog. And they knew that all individuals are useful for life because they catch insects. And even now, some people use animals as a mosquito repellent.

The frog has something in common with the elephant: both have skin attached in only a few places. Both are dressed as if in a loose robe, while our body is squeezed by a tight elastic cover. But our skin is stronger than frog skin, and there’s nothing to say about ivory skin - it’s stronger than rope.

Frogs change clothes - change their skin - four times a year and each time they eat a worn-out dress: the good stuff doesn’t go to waste, especially the skin pigments that are so difficult to produce. The skin on the frog's throat trembles not only before molting. Although under water the trembling disappears. Why exactly under water - we’ll talk about this a little later, but for now let’s talk about another interesting property of frog skin.

When going hunting, a land frog takes water from a puddle with it, and if there is no puddle nearby, it is happy with the dew. But even the dew does not swallow drops. If there is no body of water from which water can quickly be drawn through the surface of the skin, the frog crawls on the grass, and dew penetrates the body. But if water easily passes through the skin, then why doesn’t it pour out? Firstly, water is immediately included in the fabric composition. In addition, frog skin allows water to pass inward much more easily than outward. Here mucus plays a significant role, abundantly wetting the cool body. When the mucus is removed, the frog loses water right before our eyes, drying out five times faster.

Mucus stores water and helps to slip out of the enemy's paws and beak. This same mucus is something like personal dry cleaning - it keeps the frog's dress clean and does not allow germs to live on damp skin. That's why frogs are put into milk - the mucus prevents lactic acid bacteria from doing their job, and they even made an antibiotic from it. But it is not true that mucus causes warts. You can pet toads too. Warts will not appear.

Many have heard about the frog princess and the frog traveler, but hardly anyone remembers the fable or good fairy tale about a toad, although poets and writers usually find it difficult to quickly distinguish a toad from a frog by eye. Due to the fact that toads and frogs walk naked (there are no scales, no horny coverings, no feathers, no fur), in the old days they were called nothing more than naked reptiles. And the most obvious difference between such useful reptiles is their bare skin. In toads it is uneven, warty, and often dry. And beautiful frog skin is smooth, slippery, always wet and shiny.

Not only the skin, but also the figures are different: the frog is pure grace, but, alas, the same cannot be said about the toad. The toad's legs are like stumps - short and weak. Because of this, she prefers not frivolous jumping, but a solid crawling movement.

Toads do not expose themselves - they go out to get food at night. As a result, many people fail to get to know them properly. Don't worry: To the layman, toads look like just lumbering frogs with warty skin.

True, there is a difference between frogs and toads, which, really, should be taken to heart: toads do not croak! Male toads, as Professor A. M. Nikolsky wrote, “sing in a rather gentle moaning voice.” Experts claim that toads produce melodic trills like this: “oek-oek-oek” or “irrrrr-irrrrrrr”. Trills and croaking sound during the breeding season, but in their free time, tailless amphibians try not to waste energy on shaking the air. Frog song festivals last for three weeks, toads are much shorter.

There is a certain thoroughness in the toad's manner of laying eggs: the eggs are packed in long ribbons, and in frog-jumpers - in gelatinous lumps. Even toad tadpoles try not to be an eyesore to people, they behave more respectably than frogs - they stay near the bottom, and do not swim shallowly. And don’t you think that a toad is more sedate, more serious than a frog? Well, God be with her, with the toad. Time to get back to the title.

So why does the skin on the frog’s throat tremble? The reason is the simple, smooth sac-like frog lungs. Their surface is so small that it would not even be enough to cover the frog's body. And if you smooth out the ornate surface of a bull’s lungs and wrap it in this fabric, you will have a cocoon of almost a hundred layers. It is now clear that the primitive frog lungs require help - the exchange of gases through the skin. But here the frog will not miss its goal: its skin has a more powerful fan than its lungs.

The frogs even had to acquire a huge mouth “from ear to ear” in order to get more air into it. But if you open your mouth for a long time, the frog will suffocate: the lower wall of the mouth pumps air from the mouth into the lungs. Because of this, the skin on her throat trembles. Well, under water the skin does not tremble: there is no point in breathing with your lungs.

Please note that 2.5 times more carbon dioxide leaves a frog's body through its skin than from its lungs. In lizards, the skin emits only 4 percent of carbon dioxide. Some bats, mainly through the membranes of the wings, the body gets rid of 10 percent of carbon dioxide. People release 1.4% of the total carbon dioxide released by the body through a knife.

The frog's lungs are underdeveloped, which is why it mainly uses the surface of its body in water. Breathing through the lungs is carried out as follows: the bottom of the mouth drops, air penetrates through the open ones. Then abdominal muscles the remainder of the exhaust air is squeezed out, while the bottom of the mouth continues to descend. After this, the nostrils close, the bottom of the mouth rises and pushes air into the lungs.

Having collected a supply of air, the frog dives into the water. Oxygen from the lungs begins to slowly be absorbed into the blood. This allows her to stay underwater for a long time. After the supply of oxygen from the lungs is used up, the frog emerges to the surface. However, it can also receive oxygen through the skin. Experts conducted research to find out how long a frog can stay in the water without surfacing. It turned out that a toad can spend about eight days in water, and a grass frog - almost a month.

In order for the frog's skin to transmit oxygen well, its surface must always be moist. Therefore, land-dwelling amphibians love damp habitats. They hunt insects at dusk and at night, and during the day they hide from the sun under grass and leaves. Frogs feel cold to the touch because water easily evaporates through their thin skin and cools its surface. The body temperature of these amphibians is always several degrees lower than the ambient temperature.

Water also penetrates into the frog's body through the skin. The frog does not need to drink water; it only needs to press its belly against wet soil, plants, or bathe in dew.

How does a frog spend the winter?

Breathing through the skin is very important for grass frogs. great importance, since they spend the winter burrowing into the silt at the bottom of reservoirs. Ponds do not freeze to the very bottom in winter, even at very low temperatures, so frogs do not freeze either. When autumn comes, amphibians fall into a state of suspended animation, in which all life processes slow down. The amount of oxygen they need decreases, and skin respiration is enough for the frog.

Like all cold-blooded animals, frogs are characterized by reduced energy metabolism. Their activity will directly depend on the ambient temperature.

Sharp-faced frogs, unlike grass frogs, spend the winter on land. They hide under stones, snags, leaves, in mouse and mole holes. Hibernation for amphibians lasts 150-200 days and depends on the duration of the cold period. In winter, a significant part of them die; by spring, only 2-5% of frogs remain.