Why fish don't blink

Reason Why Fishes Don’t Blink


Think of a sunny day, having your sunbath on a beach happily with your friends and family. Joyfully diving and surfing through the waves, think of losing your sea googles in sea waves. Now your eyes will be burning because of seawater saltiness. As of now your only way to protect your eyeballs from this itchiness is eyelids. This is why eyelids are an important part of our body. Without eyelids, we can’t safeguard our eyes. But there is an animal that doesn’t have eyelids but it’s surviving throughout its life. Think you guessed it right yes that is fish. All the fish species don’t have their eyelids as a cover to their eyeballs. Now, we’ll see this in elaboration what’s the reason behind this evolution and why fish don’t need them for their survival.

Importance of eyelids

Why eyelids are important for living organisms? Most of the land living organisms use their eyelids as a covering from external debris, dust, and acts as a barrier for all other unwanted substances without entering our eyes. These eyelids don’t stop only with this function. In the absence of these eyelids, our eyes could be even harmed by the air as our eyes are very sensitive to air. Even people who don’t close their eyes fully while sleeping could be meet up with serious keratin tissue infection. So, these eyelids are very important for living organisms to live, particularly for human beings.

Why Do We Need To Blink

Why Humans Blink
Human blinking is a microsecond process. Research says the average blinking timing of a human is 110th of a second. You can’t imagine how fast is this nor you can’t sense your blinking. This is the reason why we call blinking an Involuntary action. These eyelids apart from the fact of protecting our eyeballs from external things it also helps to keep our eyes wet and soft. Our eyelids are made up of glands that secrete liquids to take care of our eyes. These glands secrete a liquid called meibum which keeps our eyes moisturizing. Meibum is an oily liquid hormone and this hormone protects the moisture of the cornea without leaving the moistures to evaporate.

Do fish Blink?

Anyone could say this answer if you ever observed a fish keenly. It may seem like they are blinking but actually don’t. This is because they don’t eyelids to blink. You may have a question arising in your mind. Every living organism needs eyelids to cover its eyes but why don’t any fish have them. This is because of their evolution. As these fish live in water they don’t want to protect their eyes from any dust, air, or any other foreign particles. And the primary function of the eyelids is to keep their eyes stay moistured. In the case of fish, they live in water so moisture is everywhere around them. So, they don’t need a gland to keep their eyes moistured.

Do fish Have Eyelids

Obviously, the answer to this question is no. These fish live under the water as everybody knows. So they don’t want to worry about air . And also they don’t want to protect their eyes from the air and other foreign particles as humans protect their eyes. They also have well-developed eye membranes which don’t need any help from eyelids.

Why Don’t fish Get Water in Their Eyes?

These fish live in freshwater, seawater, and in all the places where they have their surviving environment. Water comes in contact with the fish’s eyes every time. So you can’t certify that all this water enters into their eyes. All kinds of fish species are living under the water for the past billions of years. All these years they’ve become adaptive to their environment. This adaptation changed the lens of the fish’s eye to be thick shaped like an oval marble. But when it comes to us humans we’ve adapted these many years to live in an aired atmosphere. So over evolution made our eye lens become thin and flat. This is also the reason why we can’t see clearly under the water as we see normally.

Do fish Sleep

When I mention this question many people will think fish don’t sleep. But that’s completely wrong. We can’t say fish don’t sleep just because they don’t possess any eyelids to close them. Every living organism in this wonderful world needs to take some rest in its path of life. Until it pauses sometimes to take they can’t get the energy to make the rest of the life. So, assuredly fish sleep but not like human beings. These fish live in an environment where their life could be drawn to risk at any time. They should be very careful from predators that look for them and feed on them. As these fish led their lives as they walk on the needle, they have to be more conscious while sleeping. So, while sleeping these fish will not lose their full consciousness as their eyes will be open always. If you noticed fish swims in your Fish Tank at night, they will move like a trance. This means these fish are in a state of sleep. You can try feeding them but their response to the food will be slow. They take some time to sense the food and only then they will come to their food. It’s also a captivating fact that these fish move while they sleep. Poor fish that’s their fate to move while sleeping. To live they move because their life depends on their move. As the water passes through their gills it helps in their respiration. Without moving, a fish can be driven into serious problems. In the life of fish sleep is the highest luxury that they can get. They should secure themselves from predator encounters, respiratory problems, and much more.

What fish can blink

What fish blink
After many investigations, scientists found that some species of sharks can close their eyes at some critical times. Wondering how they blink? The fact is, they don’t actually blink they just cover their eyes. As these sharks have sharp noses when they eat on their total face will be in the body of their prey. As they can hurt sharks’ eyes their evolution made them form a membrane over their eyes. This nictating membrane cover shark’s eye at a time when they eat. This membrane is completely transparent and doesn’t affect shark’s vision at any time. Why not there are some exceptions in sharks who don’t own this membrane. The Great White Shark and The Whale Shark lacks this membrane. In these shark’s we can see those membrane-like structures but not in a well-developed manner. So we don’t consider them as covering membranes.

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