In male common frogs have something in common with a Blue Beard, a character from the tales of Perrault: during the mating time they turn blue throat. (By the way, the male moor frogs almost entirely blue.) But the fairytale character had seven wives, and polygamy frogs is impossible, because of the males more than females. In the scientific literature provides information about how males calling in vain-eyed friends, grief rush to carp pond and clenched their gills in an iron embrace.
Wives in the pond value - sometimes Cavaliers not release the female from the embrace even when zoologists put both of them into alcohol. But the males in the mating period, do not lose your head: is female to spawn, it makes a special sound, and the male immediately releases. And that friend is not slipped out without permission, on the front legs of the male swell so-called marriage corn. In these rough callouses are special glands. Their selection bactericidal they prevent inflammation of wounds or scratches formed on the breast of the female. Sometimes the frog arms continue until three days: the female is somehow slow to lay eggs. And the male waits nutriva corn. The experience of our ancestors tells him what to fertilize several thousand eggs should immediately, otherwise the tadpoles will not.
Like frogs in the spring are native reservoir, it is not yet clear. First thought, if they were guided by gravity, aim down. But then it turned out that they are going and from the lowlands to the lakes, located on high ground. Then they decided that they are attracted by the smell of their homes. However, they were Hiking in the pouring rain, carrying the smells. The next version was the sound - say, attracted by the cries of relatives, their joyful plait-the Scania. But frogs were on the right path and when there was dead silence. Then they began to think that they feel specific allocation of algae in the pond, where their ancestors for centuries have spawned. But then how to explain the cases when amphibians come to buried with a bulldozer pond?
...All vertebrate animals children as children are like their parents, and the frog - tadpole. His life begins in the egg, which serves as a refuge, a dining room and incubator. Top dark her spouse absorbs the sun's rays and at the same time protects not yet vilupivshayasya tadpole from ultraviolet radiation. Berry arranged like boys-stanici: if it turn dark screen down, soon he will be again at the same place, for the hardest part - yolk - located at the bottom. And another protective device: in shell eggs contains Randon that kills germs better than carbolic acid.
The door of the small house locked and a tiny guest could leave, if evolution had not supplied him with chemical skeleton key: the secret secreted by special glands tadpole, dissolves a solid shell eggs, and the baby comes into the world at large. The baby is growing, gaining strength. Through gills grow front legs, greatly increases the tongue, mouth becomes wider. Finally resolves the tail, and the little frog comes to life, having only thirty (!) stages of transformation.
The common frogs these metamorphoses take 50-180 days depending on the weather, the pond - 72-214 days. Sometimes the tadpole have to spend the winter, and only the next summer he will become a full-fledged frog.
Not one weather happy or sad kids. For example, they cannot tolerate even a small admixture of iodine. If water has salts of calcium, manganese or glucose, on the contrary, the development will go faster. But the abundance of fat in the diet inhibits growth.
By the way, tadpoles no teeth and no stomach, no. These little vegetarians consume microscopic algae, and the algae lot of alkalis. Gastric digestion with the indispensable assistance of hydrochloric acid them to anything. Where profitable intestinal alkaline. Now they've got very long intestines.
Tadpoles many enemies, the most formidable larvae of beetles. Once in the pond near Zvenigorod estimated that twenty larvae plavusa twenty days ate 40 000 tadpoles. Tadpoles and themselves can be enemies: tall individuals allocate water substances that prevent the development of frail counterparts. And samoriski, instead of offended, throw themselves into the water chemical compounds that are even more spurring growth accelerates. It turns out that part of tadpoles voluntarily gives way under the sun stronger individuals, as it goes to suicide. (Academician S. C. Schwartz, describing this phenomenon is believed that metabolic spontaneous regulation of the number of species characteristic of all populations of all wildlife).
Let's assume that the tadpole, with whom we became friends, safely turned into a frog. If his mother was a water frog, he will become "natural" animals, and if the eggs laid terrestrial frog - mostly "night". It's not in the sunshine, and in the diurnal fluctuations in air humidity: after the rain terrestrial frogs can have fun and at noon.
But sports frog people only near his home on a lot in a few square meters. Once the author of the monograph "the Frog" Professor P. C. Terentyev marked near Leningrad 230 frogs. A week later half of the tailless couch was found a short distance away from the first catch. Others a little further. Only one walked about a hundred metres. So, to travel frogs tend only in a fairy tale. By the way, mark the frog paint or ring simply: if it is knocked over on his back and hold in this position, it hardens and a few minutes to realize that the world is turned upside down.
Anyway frog something think: after four to seven attempts they fail to miss the hairy caterpillars or worms, blurry, clove oil, bleach or connected with electric wires. The lesson I remember about ten days. Maze frogs mastered worse, although taught them, of course, without mercy. When they were moving in the wrong direction, he received an electrical shock. One hundred strokes of the frog finally understood what they want, and jumped right - so to speak, traveled under duress.
Frogs must be respected. For this reason more than enough. At least that was the first live sound, once appeared on the continent, was croaking frog ancestors. Roar, roar, squeak and grunt began to shake the air much later. Bleat and laughed, too, for a long time there was no one. So, if you look into the distance of time, it is possible to come to an unexpected conclusion: our speech is laborious changed and the process of evolution croaking. However, in the very distant past amphibians likely croaked wrong. But how, no one knew except them,the ears were also only in amphibians.
Frogs croak from the fullness of the senses, their song is the oldest call for maintaining a continuous flow of life. But the intricate Nightingale warble - just a monologue of an egoist, a warning about private ownership of the land where they have built a nest. And if not nightingales, other birds would be nice to pay tribute to the vocal data of American toads and some wood frogs: they make the sound of the flute and organ, ringing like bells. And Japanese copepods frog sings just like a bird, and it specifically keep at home for delight hearing.
It is a pity that the voices of grass and marsh frogs disappoint. But this did not prevent zoologists, eavesdropping their choral rooms and intimate conversation, learn a lot of interesting things. Found, for example, that frog-ladies silent frogs-bearers and that terrestrial species of frogs silent water. In the lexicon of pond frogs usually six cries loud croaking call for renewal of nature, two soft territorial Creek, two signals on the release and a cry of alarm. If unsuspecting wah suddenly and roughly grab, it sometimes gives a shrill cry, like a cat. It is a cry of horror, parting with life.