There is no light in the deep sea, so the eyes of animals have degenerated? In fact, they are all masters of using light

There are many kinds of life on Earth, and the unique form of each organism is closely related to the environment in which it lives.

According to this logic, the eyes of animals living in the deep sea must have degenerated, right? The truth is not so. It is true that some animals that live in darkness for a long time may indeed abandon their eyes, such as naked mole rats, but deep-sea creatures do not seem to be willing to abandon their eyes that have evolved with great difficulty, so they choose to find another way and become masters of using light.

Is there light in the deep sea? There is almost no light in the real deep sea. 800 meters below the sea level, we call this area the twilight zone, which is the last area with weak light before entering the deep sea.

There is almost no light below 1,000 meters below the seabed, but the creatures here did not choose to abandon their eyes. Instead, they evolved larger and brighter eyes. The telescope fish is a typical example of this.

At first, scientists didn't know what these big eyes were used for. As humans explored the deep sea more and more, the mystery was solved little by little. It turned out that these eyes were not used to observe the surroundings, but to stare at the top of the head. In the deep sea, although there is no light around, there is still some weak and almost invisible light shining down from the top of the head, so when a creature passes by the top of the head, it will produce a weak shadow, which is the prey that the deep-sea creatures are waiting for.

It is not a very likely event to wait for a prey to happen to pass over your head, so once you encounter it, you must not miss it. Now you understand why deep-sea creatures have exaggerated teeth, which makes their hunting success rate close to 100%.

Now there is a problem. You can see others above their heads, and others can also see you above their heads. What should you do? Hide yourself. It seems that it is not difficult to hide yourself in the dark deep sea. The easiest way is to make yourself transparent. Therefore, there are always many transparent creatures in the deep sea, such as the glass squid, which is one of the best.

Having a transparent body means that you will not cast a shadow on other people's heads, but this is still useless for some guys with excellent eyesight, because there are always some things in the body that are difficult to make transparent, such as digestive glands.

Sometimes, it is because of this little opaque organ that it reveals its location. Once the location is exposed, it is absolutely a matter of life and death. After all, no one can tell how many monsters there are in the deep sea. What should we do? Since it cannot be made transparent, let it glow.

What is the use of glowing?

This is very useful. In the backlight state, the opaque digestive gland will produce a small shadow, but if the digestive gland can emit light by itself, the shadow will disappear, which makes the body in the backlight state completely transparent. Is there really such a creature? Of course, the glass squid mentioned above not only has an opaque digestive gland, but also has opaque eyes and suction cups on its tentacles, and these things happen to be able to emit light. Of course, in addition to being used to hide oneself, luminescence can also be used to lure prey, and the most representative of them is the anglerfish holding a lantern.

Anglerfish often bury themselves in the mud of the deep sea, with only a small bright light showing.

This trapping strategy is very effective. Small fish are always attracted to this small light. When they hover around the small light, their lives come to an end. What puzzles scientists is that some very weak life forms in the deep sea also have the ability to glow. For example, some types of deep-sea jellyfish have this ability. What is the use of this ability? For weak creatures, glowing in the dark deep sea is undoubtedly a suicidal behavior, but these glowing small creatures have not become extinct. What kind of mystery is hidden in it? We cannot give a definite answer now. After all, humans know too little about the deep sea. Faced with the vast deep sea, humans’ few explorations can’t even be said to be a glimpse of the leopard.

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