Lake lake frog. Lake frog: photo, characteristics
The lake frog is the largest representative of its species. Its habitat is quite wide, so the color shape varies depending on the territory. Populations are usually large.
Lake frog: description
It has an elongated body with a slightly pointed snout. The color of the upper part may vary. It is usually green, but sometimes gray and brown frogs. The entire body is covered with large dark spots of uneven shape.
Most representatives of this species have a clearly visible light stripe with small inclusions along the spine and head.
The body below is yellowish or off-white. Almost black spots are often present. The eyes are golden. IN natural environment lives up to 10 years. The lake frog grows up to 17 cm in length. It should be noted that males are slightly fewer females, but they have resonators. During the daytime, it periodically enters the water to increase the moisture content of the skin, but at night, when the air temperature drops, the frog is not in danger of drying out the surface of the body.
Habitat
The amphibian prefers such natural areas like mixed and broadleaf forests, steppes, in the southern part it can be found in deserts, in the north it inhabits some areas of the taiga. Thus, its habitat is Central and Southern Europe, Asia, Kazakhstan, Russia, Caucasus, Iran, North Africa.
The lake frog lives in reservoirs with fresh water(more than 20 cm deep). Inhabits ponds, mouths and banks of rivers, lakes. You can also see it within the city limits along the concrete banks of reservoirs, in thickets of willows and reeds. He treats the presence of a person nearby calmly.
Even to the most extreme conditions The lake frog can adapt. The habitat of individuals of this species can therefore vary greatly; they are able to survive in places heavily contaminated with waste, but in this case anomalies in development are possible.
It also easily and quickly colonizes artificial dams and reservoirs. When water bodies dry up, they can migrate to a new habitat, covering up to 12 km.
Behavior
The lake frog is a heat-loving species. It is active around the clock at temperatures from +8 to +40 °C. During particularly hot hours, it hides in the shade of plants.
The animal spends the day both on the shore and in the water. On land, it basks in the sun while remaining motionless. However, having excellent hearing and vision, at the slightest danger it jumps into the water. Here the frog finds safe place and hides, often simply hiding in the mud. It can stay in water for quite a long time. And only after he is convinced that there is no danger, he returns to his previous place.
Being a good swimmer, she still avoids fast currents, although she is not afraid of even waves.
The lifestyle of the lake frog allows it to remain over the winter in the same body of water. Sometimes it moves in search of deeper places or to springs. Where the water doesn't freeze all year round, the frog remains active constantly. Wintering lasts about 230 days, all this time it is in the silt or at the bottom. It rises to the top by mid-May, when the water warms up enough. In case of frost it dies a large number of frogs.
In areas favorable for habitat, the number of amphibians is simply amazing. Often frogs sit on the shore in huge flocks, and the surface of the reservoir is simply teeming with numerous protruding faces.
Diet
What does the lake frog eat? It all depends on age, habitat, gender and time of year. They feed both on land and in water.
Land hunting takes place just a few meters from the shore. This amphibian is a real predator. Due to its impressive size, its potential prey can be a small lizard and snake, a mouse, a chick and even a smaller frog.
Newts become lunch in the water, small fish and their own tadpoles. The main diet includes invertebrates - crustaceans, insects, mollusks, millipedes and worms.
The lake frog can catch its prey even in flight. Usually these are butterflies, flies, dragonflies. During the hunt, she actively uses her tongue, throwing it several centimeters forward. Sticky mucus helps to hold mobile prey. If the victim is on long distance, then the amphibian creeps up to her carefully. The frog can also jump very accurately, landing in the right place.
The main diet of tadpoles is small algae.
How does the lake frog reproduce?
The female reaches puberty at three years of age. Unlike other amphibians, reproduction occurs much later in time. The frog waits until the water temperature rises to +18 °C. Usually this is the end of May or June. It lays eggs in the same body of water in which it lives; it does not make special migrations for this purpose.
From the moment the first frog appears after wintering until the start of spawning, it takes from one week to a month.
They gather to reproduce in large groups. Males during this period are especially vocal and very active. When they croak, resonators swell at the corners of their mouths. Also, during the breeding season, males develop seals on the front leg on the first toe - nuptial calluses.
Their “songs” attract the attention of females. Mating occurs before eggs are laid. However, fertilization is external. This happens in almost all amphibians, and the lake frog is no exception.
The description of this process is as follows: the male embraces the female in such a way that his front paws are on the chest. Thus, the simultaneous release of sperm and eggs into the water occurs, which promotes fertilization more eggs Sometimes one female can be “hugged” by two or three males at once.
The breeding period is one month. One female can lay up to 6,000 eggs.
Lake frog tadpoles
Tadpoles appear 3-15 days after fertilization. Immediately after birth, they spread throughout the entire reservoir. During the day they are more active, at night they hide at the bottom. In just 2-3 months they reach a length of 9 cm. However, after metamorphosis, the frogs are only 1.5-2.5 cm.
The most favorable water temperature for them is + 20-28°C, at +5-6°C development stops, and at +1-2°C they die. Not all tadpoles will develop into adult lake frogs. Most of them will become food predatory fish and various birds.
Animals
Chordata
Amphibians
Anurans
Real frogs
Pelophylax
Lake frog
Pelophylax ridibundus(Pallas, 1771)
Lake frog(lat. Pelophylax ridibundus) - a species of tailless amphibians of the family of true frogs ( Ranidae).
Description
The lake frog is the most close-up view amphibian fauna of Russia: its body length can reach up to 150 mm. Muzzle lake frog pointed, body elongated. The eardrum is round. The sides of the body have well-developed dorsal-lateral folds. The hind limbs are elongated. Their fingers are connected by a swimming membrane that extends to the free end of the fingers ( full form). The ankle joints, if the limbs are folded perpendicular to the axis of the body, touch or overlap each other. The inner calcaneal tubercle is short and low. In males, external resonators of a dark gray color are located in the corners of the mouth. On the first (inner) finger of the forelimbs of males there is a skin thickening - a callus, which grows during mating.
Top color green, brown, gray or Brown various shades with dark spots (morph maculata), grouped on both sides of the spine, along which there is often a light narrow stripe (morph striata). On the hind legs, dark spots form transverse stripes. Abdominal side dirty yellowish-white with dark spots or dots.
Spreading
The lake frog is common in the South and Central Europe, Front and Central Asia, in North Africa. IN Eastern Europe distributed up to 60° N. sh., found in Crimea, the Caucasus, and Kazakhstan. IN Saratov region is the most common species among amphibians.
Habitats and lifestyle
Possessing high ecological plasticity, frogs live in both small rivers, lakes, ponds, canals, oxbow lakes, and along the banks large rivers: Volga, Bolshoi and Maly Irgizov, Medveditsa, Khopra, Bolshoi and Maly Uzeni. They prefer bays and oxbows overgrown with aquatic and semi-aquatic vegetation. In many ecosystems it reaches high numbers. When small bodies of water dry out, frogs are able to migrate over distances of up to several kilometers.
The lake frog spends its entire life in or near water on the shore. Active almost around the clock. During the day, frogs from time to time briefly go into the pond to replenish the supply of moisture in the body. At night they are on land, since with more low temperatures frogs are not in danger of drying out.
Awakens in the first half of April. Males appear first, attracting females with a mating chorus: “warr... warr... warr.” During this period, they float on the surface of the water, sometimes forming large accumulations. After 1-3 weeks, spawning begins. Egg laying begins at water temperatures from +15 to +18 °C. During mating, the male embraces the female behind her front paws so that his paws meet on her chest. The female lays eggs in small portions, attaching them to aquatic plants. The clutch has the shape of a ball, the egg with a diameter of 2 mm is covered with a mucous membrane of 7-9 mm. The number of eggs depends on the size of the female and ranges from 650 to 10,000 pieces. The spawning period is very extended and takes up to 1.5 months.
The larvae emerge from the egg shells 5-10 days after laying eggs, depending on the water temperature. Their average increase is up to 1 mm/day. Active feeding in tadpoles is observed after the yolk reserve has been consumed and the mouth has broken through, usually at a length of 16 mm. They feed on single-celled diatoms or green algae, protozoa, flagellates, and small crustaceans. With age, their diet expands. Metamorphosis occurs after 80-90 days and lasts 5 days. Fledglings 18-28 mm long appear in late June - August. Sexual maturity occurs in the second or third year of life when the body size of males is more than 65 mm and females are 80 mm.
Life expectancy in nature is 6-8 years.
Lake frogs go to winter in late September - October. They overwinter at the bottom of reservoirs, usually in holes with a muddy bottom. In non-freezing reservoirs they can be partially active all winter. Activity stops at water temperatures from +5 to +8 °C.
Nutrition
The lake frog feeds mainly in the morning and afternoon hours, foraging both in water and on land. During the active period, she eats a large amount of food. The number of animals it catches daily ranges from 10-15 to 20 or more specimens, and the biomass utilized is more than 1000 mg. The diet of lake frogs is based on insects, among which Coleoptera, Hymenoptera and Hemiptera predominate. Representatives of other classes in frog nutrition are of less importance, with the exception of gastropods. In spring and early summer, the diet of lake frogs is often saturated with amphibian larvae, including those of their own species. Along with invertebrates, their prey includes fish fry, amphibians (red-bellied toad, green toad, sharp-faced frog, etc.), reptiles (snap lizard, young common and water snakes), some species of birds and small mammals.
Limiting factors and status
The death of frogs occurs when water bodies dry out during drought. Mortality is especially high during development. Frogs also die from predators. Thus, they are included in the feed of fish (perch, common pike, pike perch, etc.), reptiles (common grass snake, Nikolsky’s viper), birds (gray and great white heron, great bittern, common buzzard, hoodie, etc.) and mammals (muskrat, red fox, mustelids). Moreover, in some places in the region, lake frogs are the basis of the food supply common snake. Lake frogs in the Saratov region are often caught as laboratory animals for scientific, medical and educational institutions.
On the territory of the Saratov region, the lake frog is a common, sometimes numerous animal. IN special measures The species does not need protection.
Literature
- Fauna of the Saratov region. Book 4. Amphibians and reptiles: Textbook. allowance / G. V. Shlyakhtin, V. G. Tabachishin, E. V. Zavyalov, I. E. Tabachishina. - Saratov: Publishing house Sarat. University, 2005. - pp. 32-35
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From the family of true frogs ( Ranidae).
Appearance
The body length is 6-13 cm, weight - up to 200 g. The body is elongated, the skull is oval, the muzzle is slightly pointed. On top, the body is colored brown-green in different shades with dark spots. A light stripe runs along the head and spine of most individuals (up to 90%) varying degrees expressiveness. Bottom part the body is colored dirty white or slightly yellowish, in most cases with numerous dark, sometimes black spots. The eyes are bright golden in color. The tadpole is light olive in color, pear-shaped, green or other colors.
Spreading
The lake frog is common in Southern and Central Europe, Western and Central Asia, and North Africa. In Eastern Europe it is distributed up to 60° N. sh., found in Crimea, the Caucasus, and Kazakhstan. In the east - to Lake Balkhash. It was unintentionally introduced into Kamchatka, where it successfully took root and lives in Lake Khalaktyrskoye, reservoirs of the Paratunka Valley (the villages of Paratunka and Termalny), in the village of Esso, etc. On the peninsula, its distribution is mainly associated with.
Tomsk populations formed in non-freezing reservoirs and lakes, reclamation canals, where warm wastewater from power plants, enterprises and residential buildings is discharged. In the city limits of Tomsk, it lives in the Mavlyukeevsky and University lakes. These reservoirs are located on the verge of the second and third terraces of the floodplain of the Tom River, surrounded by private estates. In the southeast Novosibirsk region The lake frog inhabits the Ob valley in the Ordynsky and Suzunsky regions.
Lifestyle
Lake frogs are the largest amphibians of the Palearctic. There are giants up to 17 cm long. Females are usually larger than males.
The coloring of the back helps the lake frog to remain invisible among coastal and aquatic vegetation. This is greatly facilitated by the bright, distinct stripe, which seems to dismember the body and disrupt the integral perception of its outlines. In water, this stripe is very similar to the stems of aquatic plants, which turn bright green on dark background bottom.
The lake frog lives in permanent, fairly deep (more than 20 cm) reservoirs. Most often these are oxbow rivers, ponds, ditches, lakes, but often it can be found along river banks. Active almost around the clock. In cases of danger, the lake frog usually hides in the water. She hunts mainly on land, along the banks of reservoirs, here she can most often be found at the most warm time days - from 12 to 17 hours.
Lake frogs usually overwinter in the same reservoirs where they live during the warm season, but sometimes migrate to warmer areas. deep places where there are springs. They leave for the winter when the water temperature drops to 8-10 °C. In non-freezing reservoirs with warm water frogs are active almost all winter.
Diet and natural enemies
Like all frogs, the lake frog feeds on various insects: dragonfly larvae, water beetles and their larvae, and mollusks. If there is not enough ground food, lake frogs eat tadpoles of their own species in large quantities, and are also able to feed on fish fry. But in natural reservoirs, the role of fish in the nutrition of lake frogs is minimal. Young tailless amphibians, both their own and other species, often become prey for the lake frog. Unlike other amphibians, this large frog sometimes attacks small mammals(voles, shrews), small birds, chicks, young snakes (most often, snakes). The lake frog itself is a victim of predatory fish and reptiles, and often becomes prey for many species of birds and mammals.
Many frogs are captured for educational, medical and scientific purposes. Along with the grass frog (Rana temporaria), the lake frog is the main object of such trapping. In the 1970-1980s. In the USSR (mainly in Ukraine, Russia, Azerbaijan, Uzbekistan, Kazakhstan and Kyrgyzstan), many hundreds of thousands of individuals of these two species were caught annually. For example, only the Alma-Ata zoo in the 1980s. caught about 250,000 lake frogs annually. Around the same years, many thousands of individuals were caught in the lower reaches of the Volga, Danube and some other rivers in the south Soviet Union for the export of frog legs. For example, 4.2-56.2 tons of frogs were exported annually in 1974-1980. from Odessa region. Attempts to create frog farms have not been successful.
Reproduction
The lake frog is characterized by a classic croaking sound. In males mating season When singing, gray balls are inflated in the corners of the mouth - resonators, which serve to amplify the sound. It is interesting that the specific Latin name translated into Russian means “Laughter”. Male lake frogs make their first voice test when the water warms up to 14-16 °C during the day. Mating and spawning begin only when the water warms up to at least 16 °C. Spawning begins in the warmest and most wind-protected areas of water bodies. The breeding period takes at least 30-35 days. Most individuals choose for breeding rather deep reservoirs that are overgrown with plants.
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Notes
Literature
- Amphibians. Pauzuny: Entsyklapedychny davednik. Mn., BelEn, 1996. ISBN 985-11-0067-6
- Lyapkov S.M., 2014. Lake frog ( Pelophylax ridibundus) in thermal reservoirs of Kamchatka // Zool. magazine T. 93. No. 12. P. 1427-1432. DOI: 10.7868/S0044513414120101
- Lyapkov S. M., 2014. Lake frog ( Pelophylax ridibundus) in Kamchatka: distribution, habitats and features of population structure // Conservation of biodiversity of Kamchatka and adjacent seas. Materials of the XV International scientific conference. Petropavlovsk-Kamchatsky. P.62-66.
Links
- on slounik.org(Belorian)
An excerpt characterizing the lake frog
None of the Russian military leaders, except Kutuzov, understood this. When the direction of flight of the French army along the Smolensk road was determined, then what Konovnitsyn foresaw on the night of October 11 began to come true. All the highest ranks of the army wanted to distinguish themselves, cut off, intercept, capture, overthrow the French, and everyone demanded an offensive.Kutuzov alone used all his strength (these forces are very small for each commander in chief) to counteract the offensive.
He could not tell them what we are saying now: why the battle, and blocking the road, and the loss of his people, and the inhuman finishing off of the unfortunate? Why all this, when one third of this army melted away from Moscow to Vyazma without a battle? But he told them, deducing from his old wisdom something that they could understand - he told them about the golden bridge, and they laughed at him, slandered him, and tore him, and threw him, and swaggered over the killed beast.
At Vyazma, Ermolov, Miloradovich, Platov and others, being close to the French, could not resist the desire to cut off and overturn two French corps. To Kutuzov, notifying him of their intention, they sent in an envelope, instead of a report, a sheet of white paper.
And no matter how hard Kutuzov tried to hold back the troops, our troops attacked, trying to block the road. The infantry regiments are said to have charged with music and drums and killed and lost thousands of men.
But cut off - no one was cut off or knocked over. And the French army, pulled together tighter from danger, continued, gradually melting, its same disastrous path to Smolensk.
The Battle of Borodino, with the subsequent occupation of Moscow and the flight of the French, without new battles, is one of the most instructive phenomena in history.
All historians agree that external activities states and peoples, in their clashes among themselves, are expressed by wars; that directly, as a result of greater or lesser successes of the military, increases or decreases political force states and peoples.
No matter how strange the historical descriptions are of how some king or emperor, having quarreled with another emperor or king, gathered an army, fought with the enemy army, won a victory, killed three, five, ten thousand people and, as a result, conquered the state and an entire people of several millions; no matter how incomprehensible it may be why the defeat of one army, one hundredth of all the forces of the people, forced the people to submit, all the facts of history (as far as we know it) confirm the justice of the fact that greater or lesser successes of the army of one people against the army of another people are the reasons or, according to at least, significant signs of an increase or decrease in the strength of nations. The army was victorious, and the rights of the victorious people immediately increased to the detriment of the vanquished. The army suffered defeat, and immediately, according to the degree of defeat, the people are deprived of their rights, and when their army is completely defeated, they are completely subjugated.
This has been the case (according to history) from ancient times to the present day. All Napoleon's wars serve as confirmation of this rule. According to the degree of defeat of the Austrian troops, Austria is deprived of its rights, and the rights and strength of France increase. The French victory at Jena and Auerstätt destroys the independent existence of Prussia.
But suddenly in 1812 the French won a victory near Moscow, Moscow was taken, and after that, without new battles, not Russia ceased to exist, but the army of six hundred thousand ceased to exist, then Napoleonic France. It is impossible to stretch the facts to the rules of history, to say that the battlefield in Borodino remained with the Russians, that after Moscow there were battles that destroyed Napoleon’s army.
After the Borodino victory of the French there was not a single, not only general, but any significant battle, and french army ceased to exist. What does it mean? If this were an example from the history of China, we could say that this phenomenon is not historical (a loophole for historians when something does not fit their standards); if the matter concerned a short-term conflict, in which small numbers of troops were involved, we could accept this phenomenon as an exception; but this event took place before the eyes of our fathers, for whom the issue of life and death of the fatherland was being decided, and this war was the greatest of all known wars...
The period of the 1812 campaign from the Battle of Borodino to the expulsion of the French proved that a won battle not only was not the reason for the conquest, but was not even constant sign conquests; proved that the power that decides the fate of peoples lies not in the conquerors, not even in armies and battles, but in something else.
French historians, describing the position of the French army before leaving Moscow, claim that everything in Great Army everything was in order, except for the cavalry, artillery and convoys, but there was no fodder to feed the horses and cattle. Nothing could help this disaster, because the surrounding men burned their hay and did not give it to the French.
The won battle did not bring the usual results, because the men Karp and Vlas, who after the French came to Moscow with carts to plunder the city and did not personally show heroic feelings at all, and all the countless number of such men did not carry hay to Moscow for the good money that they They offered it, but they burned it.
Let's imagine two people who went out to duel with swords according to all the rules of fencing art: the fencing continued for quite some time. for a long time; suddenly one of the opponents, feeling wounded - realizing that this was not a joke, but concerned his life, threw down his sword and, taking the first club he came across, began to swing it. But let us imagine that the enemy, having so wisely used the best and simplest means to achieve his goal, at the same time inspired by the traditions of chivalry, would want to hide the essence of the matter and would insist that he, according to all the rules of art, won with swords. One can imagine what confusion and ambiguity would arise from such a description of the duel that took place.
The fencers who demanded fighting according to the rules of art were the French; his opponent, who threw down his sword and raised his club, were Russians; people who try to explain everything according to the rules of fencing are historians who wrote about this event.
Since the fire of Smolensk, a war began that did not fit any previous legends of war. Burning of cities and villages, retreat after battles, Borodin’s attack and retreat again, abandonment and fire of Moscow, catching marauders, rehiring transports, guerrilla warfare– all these were deviations from the rules.
Napoleon felt this, and from the very time when he stopped in Moscow in the correct pose of a fencer and instead of the enemy’s sword he saw a club raised above him, he never ceased to complain to Kutuzov and Emperor Alexander that the war was waged contrary to all the rules (as if there were some rules for killing people). Despite the complaints of the French about non-compliance with the rules, despite the fact that the Russians, the people of higher position, seemed for some reason ashamed to fight with a club, but wanted, according to all the rules, to take the position en quarte or en tierce [fourth, third], to make a skillful lunge in prime [the first], etc. - the club of the people's war rose with all its formidable and majestic strength and, without asking anyone's tastes and rules, with stupid simplicity, but with expediency, without considering anything, it rose, fell and nailed the French until those until the entire invasion was destroyed.
Common toad
syn. Pelophylax ridibundus
The entire territory of Belarus
Family True frogs (Ranidae).
In Belarus, mosaically distributed throughout the territory, quite often dominates in amphibian complexes of coastal ecosystems.
Belongs to the group of green frogs. The largest species among our amphibians. Maximum length body reaches almost 10 cm. Body length of males is 6 cm (5–8 cm), females 5.6 cm (3.7–8.5 cm), weight up to 200 g. The body is elongated, the muzzle is slightly pointed, but generally oval . The eardrum is round. The skin is smooth. The most important distinctive features: if the shins of the legs are pressed to the thighs and placed perpendicular to the longitudinal axis of the body, then the ankle joints go one after another; the inner calcaneal tubercle is low, usually more than 2 times shorter than the first toe; The males' resonators (balls in the corners of the mouth that inflate) are gray, sometimes almost black.During the breeding season, males develop thickenings on the first toe of the front leg - nuptial calluses.Females are usually larger than males.
From above the body is colored brownish-green with a predominance of brown, brown, green or sometimes olive shades. There are large dark spots on the back that vary in number, size and shape. Along the head and spine of the majority of individuals (up to 90%) living in Belarus there is a light stripe of varying degrees of expressiveness (in 0.3-0.5% of individual specimens it is zigzag).
The lower part of the body is colored off-white or slightly yellowish, in most cases with numerous dark, sometimes black spots. There are transverse stripes on the hind leg. The eyes are bright golden in color.
The larva, or tadpole, is light olive in color and pear-shaped. The space between the eyes is more than 2 times wider than the distance between the nostrils. On upper lip 2-3 oral discs, 3 rows of teeth on the lower one.
Leads a strictly littoral lifestyle. The lake frog lives in permanent, fairly deep (more than 20 cm) reservoirs. Most often these are oxbow lakes, lakes, ponds, ditches, but often it can be found along the banks of large and small rivers. In Belarus, the lake frog is distributed unevenly, the population density ranges from 1-2 to 300-550 individuals per 100 m of coastline. The largest number is typical for southern regions republics.
Active around the clock, but mainly during the day. The most active are the most warm periods days (from 12 to 17 hours). Hunt for the most part on land, along the banks of water bodies. In water it usually hides from danger, diving from banks, hummocks or from the leaves of aquatic plants. During daytime activity, frogs replenish their body moisture reserves in the pond. At night, at lower temperatures, they are not in danger of drying out, so they can stay on land for a long time. Young, immature frogs are characterized by great activity in obtaining food during the summer; it is slightly less in females; in males, feeding activity is almost half as much as in females.
Like all frogs, the lake frog feeds various insects(68-95% of the diet), of which 27% belongs to flying forms. Various aquatic invertebrates (dragonfly larvae, beetles and their larvae, mollusks) are also common food. In some cases, when there are many fish fry and tadpoles in reservoirs, the proportion aqueous forms reaches 70%, are able to feed on fish fry in places where they are concentrated in fish ponds. But in natural reservoirs the role of fish in feeding lake frogs is minimal. Cannibalism is very pronounced, especially in areas of high abundance, where up to 98% of larvae and tadpoles are eaten during the entire active period. Young frogs of both their own and other species often become prey for the lake frog. Unlike other amphibians, this large frog sometimes attacks small mammals (voles, shrews), small birds, chicks, and young snakes (usually stung).However, the composition of the diet varies greatly. In some places, terrestrial insects play a significant role in nutrition (up to 80-90%).
During the hunt, the frog throws its sticky tongue far forward with lightning speed. Prey stuck to the tongue is grabbed by jaws equipped with small teeth.
The lake frog itself is a victim of fish (pike, pike perch, perch, burbot), and reptiles (snakes, vipers). It often becomes prey for many species of birds (gulls, terns, grebes, ducks, storks, herons, bitterns, rollers, crows, rooks, shrikes, shrikes and birds of prey). Among the mammals it is eaten by shrews, rats, wolves, foxes, raccoon dogs, weasels, ferrets, minks, martens, badgers, otters and even domestic cats.
The lake frog is characterized by a classic croaking or loud rumbling “whorrr...” or “crowu...”. However, in the lake frog, male vocal activity continues after the breeding season. When males sing, gray balls are inflated in the corners of their mouths - resonators, which serve to amplify the sound. It is interesting that the species Latin name Rana ridibunda translated into Belarusian language means “ragatukha” or in Russian “laughter”. Male lake frogs make their first voice test when the water warms up to 14-16°C during the day, usually at the end of April.During the breeding season, the chorus of males sounds throughout almost the entire day and is interrupted only from 03.00 to 06.00 (cooling time).
During the breeding season, males are very active and loud. Mating and spawning begin from the beginning of May at a water temperature of 15-20°C.Spawning begins in the most heated and wind-protected areas of water bodies. Not all frogs lay eggs at the same time: their breeding period is always very extended and takes at least 30-35 days with a peak of spawning in May and the last fresh clutches in mid-late June at a water temperature of at least 17-18°C.
The spawning sites of the lake frog are permanent. Most individuals choose rather deep reservoirs for breeding, which are overgrown with elodea, pondweed, arrowhead and other plants. Sometimes spawning occurs in shallow small reservoirs that warm up well and are located next to permanent ones. This is typical for individuals that begin reproducing first.
Fertilization in this species is external. Caviar is deposited in the form of a lump formed as a result of gluing of the mucous membranes of the face. The diameter of the lake frog egg is 1.5-2 mm, and the entire egg is 7-8 mm. The upper half of the egg is dark brown and the lower half is white. The female lays eggs in portions (150-400) per aquatic plants, as a rule, at a depth of 0.6-1.3 m. Fertility 1032-6200 eggs. The development time of eggs depends on warm weather and water warming.
Larvae appear in 5-9 days and develop in 75-100 days. The tadpoles have quite a long tail surrounded by a well-developed fin. The external gills are divided into a series of lobes. The body color of tadpoles is light yellow or brown. Having reached approximately 30 mm in length, the tadpoles turn green. Grows up to 80-100 mm. The larval period of development of the lake frog is one of the longest among tailless amphibians. It takes 80-90 days. But the tadpoles of the lake frog grow faster than those of many other species. Best Temperature water temperature for them is 18-28° C. At a water temperature of 5-6° C, the development of tadpoles stops, and at 1-2° C they die. The sizes of underyearlings that have undergone metamorphosis vary from 17-35 mm.
The lake frog is the largest species of tailless amphibians in the domestic fauna, belonging to the group of green frogs: its length reaches 15-17 cm. Its swimming membranes are very well developed. Males are equipped with paired external lateral resonators of dark gray color, which are located in the corners of the mouth; when inflated they are light gray. On the first finger of the forelimbs of males, a solid dark gray nuptial callus develops. The color of the lake frog is thick green, olive, gray or brown in various shades on top. On the back of many individuals there are large, much less often small, spots and/or a light longitudinal stripe, sometimes greenish. The underparts are white, gray-white or yellowish, often with small dark gray spots.
The range of the lake frog is huge and extends from eastern France in the west to eastern Kazakhstan in the east. The northern border runs through Holland, Germany, Poland, Lithuania, Belarus, the central regions of the European part of Russia to Vyatka and Perm regions, through Bashkiria and Southern Urals further southeast to eastern Kazakhstan. In the south, the range covers the Balkans, western Turkey, the entire territory former USSR, except for southern Tajikistan and part of Transcaucasia, northern Iran and Afghanistan, the Ili River region in northwestern China. The species is absent in high mountain areas, as well as in arid deserts. The lake frog is ecologically very flexible and lives in a variety of forest landscapes (mixed and deciduous forests), forest-steppe, steppe and even desert zone, found on the plain and in the mountains up to an altitude of 2438 m above sea level (Caucasus). It prefers open areas everywhere and stays in or near water bodies, usually not moving more than 20-50 m (one individual was found 500 m from the water body). Through river beds it penetrates into forested areas. Lives in reservoirs of cities and towns. It can be found in very different bodies of water with stagnant, less often flowing water: in pits, large puddles, reed swamps, springs, ponds, oxbow lakes, irrigation canals, lakes, rivers. Most often inhabits large open bodies of water. Fast current tries to avoid it, although he swims well and is not afraid of waves. Frogs are found in brackish water and even in the sea near river mouths and in estuaries. Easily colonizes artificial reservoirs: dams, reservoirs, fish ponds, rice fields etc. In Kalmykia, when water bodies dry up, frogs can migrate long distances, sometimes from 5 to 12 km. The lake frog species are active almost around the clock, especially in summer, except for the hottest hours in the south. During cooler times in spring and autumn, animals are active during the day.
In spring, frogs awaken in February in Kalmykia, March-April in the Caucasus, in April in the Central Black Earth region of Russia, at a temperature not lower than 10°C. The first days the animals are little active. They begin to reproduce at water temperatures of 10-12°C and above. Males appear first and attract females with loud, sometimes deafening concerts. The breeding season is extended and lasts 23-27 days. Eggs are laid immediately or in portions of 72-300 pieces at a depth of 30 cm to 1 m. Total eggs spawned by the female range from 1,100 to 16,400. Embryonic development lasts 3-10 days. The hatched larvae reach a length of 5-8 mm. Larval development covers 40-100 days. The total length of the tadpole usually ranges from 40 to 90 mm (including tail). However, there are known cases of developmental delay, including abnormal ones, which lead to rapid growth and gigantism. Some of these tadpoles, reaching a length of up to 165 mm, were mistaken for larvae common spadefoot. No more than 0.4-5.5% of laid eggs undergo metamorphosis. Fledglings appear in Transcaucasia in March, in the Central Black Earth region of Russia in July-September. Their body length is 16-30 mm. Sexual maturity in the lake frog occurs at the age of two years with a body length of 65-70 mm in males and 70-80 mm in females. The maximum life expectancy in nature is at least 11 years.
The composition of the lake frog's food depends on the season, terrain, as well as the sex and age of these amphibians. Insects predominate, usually terrestrial, and are found both during the day and at night. Mostly these are beetles, Hymenoptera, Diptera, aphids, especially in young frogs, and less often butterflies. In addition, frogs consume arachnids, crustaceans, and earthworms. Large individuals Can grab small birds and mammals. Cannibalism is often observed. In the literature, especially in the fisheries literature, one can find the statement that the lake frog causes serious harm by eating fish. In fact, this type of feed constitutes a minor component diet. Tadpoles eat various algae, as well as small aquatic invertebrates. The frogs themselves, as well as tadpoles, are prey for many vertebrates (some fish, snakes, many birds and mammals), as well as invertebrate animals (predatory water bugs, dragonfly larvae, leeches, etc.).
Frogs go to winter at the end of September - October in the European part, in the second half of October - November in the Caucasus, at soil, water and air temperatures of 6°, 7° and 11°C, respectively. Frogs overwinter at the bottom of deep, usually non-freezing reservoirs, burrowing into the silt, preferring, if possible, places with running water. There are known cases of gerbils wintering in burrows. In case of death at the end of winter, a large number of frogs die. In warm cooling ponds of power plants, where the water temperature in winter does not fall below 13°C, animals are active all winter. In the Caucasus they are found in warm winters in January and February.
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