Flounder is a fish that has a flat body, families Kambalov, subfamilies Kambalopodobnye.
All representatives of this family haveflattened form asymmetrical, reminiscent of a pancake, which either lies on the bottom of the sea, or floats, but only on one side, and the eyes of the fish are located side by side.
Previously, they did not have this feature,moved standard and had a normal shape. So why flatfish? Because so it became easy prey for enemies, and it was necessary to evolve, after which these fish began to swim and lie only on one side. And after thousands of years they still found a flat form. This meant that one eye would remain located to the ground, and the mouth was in an uncomfortable position for eating. In this connection, in the course of a long evolution, the lower eye gradually moved upward, for convenience. Thus, both visual organs were on an asymmetrical head, on the one hand, on which fins also are located.
Хотя у речных мальков при рождении глаза located on both sides of the head. As they grow, they shift to one side, most often to the right. The upper part has a color, the reverse always remains white. River species grow to fifty centimeters, weighing up to three kilograms. Marine species can reach much larger sizes. They have an unequal color, a straight tail, and a mouth that is perpendicular to the bottom.
Is able to change color for masking purposes.But this feature is characteristic only for sighted species. For greater secrecy he sprinkles himself with sand and merges with the bottom, quietly waiting for the prey. So they almost completely hide under the ground, leaving the upper part of the head with the eyes outside.
Происходит это очень ловко, при совершении Wave-like movements: the ground rises, and in the formed deepening the fish continues to be buried. The underside is rough, resembling sandpaper, it helps it to move freely on sharp stones and pebbles.
These fish move very little.Swim at the expense of dorsal and anal fins. They basically move in their usual state, but in case of danger they can turn over to the rib and continue to move in this position until they sink to the bottom to dig into the ground.
They feed on crustaceans, mussels and fry, worms andsmall bottom fish, grabbing it with a throw when it comes close. They have developed strong teeth. Spawning, depending on the habitat, from January to May. The female swallows up to two million eggs.
Why flatfish?Physics treats this as follows. This fish lives at great depths where the pressure is very high. And in order not to experience overloads, it has this form. The body from above is subject to the minimum pressure.
Why flatfish? This is also due to the bottom life, which contributes to the redistribution of the pressure load.
Most of the representatives of the family live incoastal waters, at a moderate depth, and only some overcome a distance of more than 1 thousand meters to search for food. Certain species live in salt water. They can climb up the river.
Why flatfish? The scientific explanation is as follows. Based on the fossils found, scientists have built a chain of evolutionary development of this family.
Flounder is a relative of trout and herring, andher body was originally oriented in a vertical plane. Consequently, the ancestors fell to the bottom sideways, not belly. And at first the fish had to rise on the fin to see better, then this need disappeared, but the reception was preserved.
Now it is clear why the flounder is flat.
