How many eyes does a four-eyed fish have? Detailed answer

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How many eyes does a four-eyed fish have? Detailed answer

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How many eyes does a four-eyed fish have?

In the lagoons of Central America and the northern part of South America, two species of fish from the carp-tooth order live. These relatively small fish, whose length does not exceed 20-30 centimeters, are called four-eyed, although they, like all vertebrates, have one pair of eyes. The four-eyed birds spend most of their time in the upper layer of water.

Slowly swimming, they expose half of their eyes above the water and thus simultaneously observe what is happening not only in the water, but also in the air. They manage to do this due to the fact that each eye is divided in half by a horizontal partition.

Not only the cornea is divided into two parts, but also the retina. And the focusing lens - the lens - is not spherical, like in all fish, but oval. Its upper part is flatter, and the lower one is more convex. Such a lens gives a clear image of objects both under water and above its surface on the retina.

Author: Kondrashov A.P.

Random interesting fact from the Great Encyclopedia:

Is it true that the nightingale only sings at night?

Poets have not dedicated as many lines to any bird as to a nightingale. His singing is considered the most beautiful, and no one has yet been able to describe it well enough. By the way, the first attempt to do this belongs to the ancient Greek playwright Aristophanes! According to the poets, the nightingale sings only at night at almost any time of the year. But it's not. The nightingale is a migratory bird, and in England, for example, its singing can only be heard from mid-April to mid-June. The nightingale does not fly to Ireland, Wales or Scotland.

In continental Europe, nightingales are especially numerous in the south, and they reach Iran, Saudi Arabia, Ethiopia, Algeria and Ghana in western Africa. Only male nightingales sing. His song is an expression of courtship for his girlfriend, who sits silently on a bush or tree somewhere nearby.

The singing of the nightingale can be heard day and night, but during the day it is not very audible because of the voices of other birds. The nightingale sings until the female hatches the chicks. Then he falls silent so as not to attract enemies to the nest. He is always on the alert and makes short exclamations that tell his girlfriend that all is well, or warn of danger.

Although the nightingale sings the most beautiful songs, its plumage is very plain. Males and females are very similar to each other - a reddish-brown back and a dull gray-white abdomen.

The nightingale's nest has a somewhat unusual appearance. It is located directly on the ground or low above it. Outside, the nest consists of vertically arranged leaves. In the middle of this structure is a deep bowl-shaped depression, neatly lined with fibers from the roots of plants. It is built fragile and can be destroyed from one touch. It contains four to six dark olive eggs.

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Scientists from Argentina managed to teach bees to pollinate only sunflowers, proving that these insects can be trained. Now the researchers hope to replicate this trick with other crops.

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Subsequently, this flavoring was added to hive food, as a result of which most bees began to collect pollen and nectar exclusively on these plants, significantly increasing the yield of nearby fields. In conducting this experiment, the researchers relied on the work of their colleagues, who were able to find out that memories and previous experiences associated with smells influence the taste preferences of bees.

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