Can fish without eyelids also "blink"?

On Monday morning, do you feel drowsy and sleepy at the table, can't lift your eyelids, and can't wait to use a toothpick to support them to not close them?

Without him, only sleepy

Source 丨 Screenshot of cartoons

Whenever this kind of trapped, do you have to be strong, do you envy the fish without eyelids? If people have no eyelids like fish, can they sleep with their eyes open, can they not know the ghosts?

Wake up.

Every time it comes to "sleepy", everyone will unconsciously connect with the eyelids, as if as long as they support the eyelids, they can resist the invasion of the sleeping demon. Including humans, many animals have eyelids that can be closed. Today, let's talk about the eyelids. 1

1. What is the use of eyelids?

Eye, the formal name is the eyelid, is an important organ that protects our fragile eyes. Taking human eyes as an example, the eyelids can be divided into upper eyelids and lower eyelids. The place where the upper and lower eyelids are connected are called 眦 (that is, the "眦"), which is the corner of the eye. The corners of the two eyes are close to the nose called inner pupa, and those near the temple are called outer pupa.

Source 丨 Wikipedia Encyclopedia

The most important thing about eyelids is undoubtedly protecting the eyeballs. When closing your eyes, the eyelids can protect the corneal from being traumatized. When opening your eyes, the eyelashes on the eyelids can also play the effect of blocking dust and weakening strong light.

In the animal world, most vertebrates have eyelids, but they are not absolute. For example, many geckos do not have eyelids that can be moved. There is also a type of vertebrate that is usually considered "no eyelid", which is the fish we mentioned earlier.

2. Does the fish really have no eyelids?

Searching "animals without eyelids" online, the first answer is often fish. But the scope of fish is so large, so many types, are there really no eyelids?

Let's take a look at two fish without eyelids, but we can "blink".

The first is the bouncing fish. Plastic fish is a general name of PerioPhthalmini (PerioPhthalmini). This type of fish belongs to the shrimp tiger fish eyes, and the eyebrows are shrimp and tiger fish. Most of them live on the beach by the sea, and most of the day stay on the shore. Because they need to maintain a good field of vision above the water, their eyes grow on the top of their heads like a subtraction. There are no eyelids or lacrimal glands. When the eyes need to be kept moist, the eyes will shrink back into the eye socket, which looks like a blink of an eye.

By blinking the eye, keep the eyes moist and bouncing fish

Source 丨 Discovery

There is also a type of fish that is very popular on the Internet recently. This is the lamp eye fish (ANOMALOPIDAE). Light -eyed fish belongs to the golden eye bream. Below their eyes, there is a half -moon -shaped luminous device. Among them, there are light -emitting bacteria that are symbiotic with it, which can emit cyan or white light.

Light -eyed fish live in groups. During the day, there are no lights or darkest places such as reef caves, shipwrecks, etc., and they will come out for food at night. The lumines under their eyes can be freely opened or closed by flipping, so it seems to give people a feeling of "blinking", but it is not the eyelids of the light -eyed fish that block the luminous. There is nothing to block its eyes, only the luminous device is blocked.

Light -eyed fish in the dark environment can see that they are turning and turning off the litter.

Source 丨 YouTube: Broken Brain

We raised two examples of fish that can blink but have no eyelids. So is there any fish with eyelids?

In fact, you have not only seen the fish with eyelids, but it is likely to eat it. This eyelid is a transparent membrane structure composed of lipids, and is called adipose eyes based on its constituent components.

Last eyelids are mostly common in seawater fish, including milkfish, catfish, catfish and catfish, which have this structure, many of which are common edible fish. The types of fish are different, and the thickness and shape of the lipid eyelids are also different. This layer of transparent film may cover the eyes of the fish or wrap around the eyes of the fish. The name of famous milkfish (covering fish) in Taiwan is likely to be obtained by the lipid eyelid covered with the eyes.

Fish's fat eyelids (labeled outlines with black wires)

Source 丨 wikicommons

However, this lipid eyelid cannot be moved. According to scientists, its main role may be to help fish enhance vision, filter ultraviolet rays, and protect the impact damage of foreign objects.

3. Is there a eyelid that can be moved by fish?

Seeing this, the fish you see can "blink" but have no eyelids, either with eyelids but cannot move. So is there a "eyelid" that can cover the eyes that can be covered?

There are also sharks. In many documentary, we can see that some sharks will cover a layer of opaque film on the moment of attacking prey. This is its "eyelid".

Great green shark's instantaneous film

Source 丨 see watermark

This layer of eyelids of the shark is called Nictitation Membrane, also known as the third eyelid. Instantic membranes are usually thin, and when covering the eyes, you can still have a certain vision while protecting the eyeball.

This structure has this structure on the eyes of most crawls, toads and most crawled animals, and birds, and can also be found on a part of mammals. The most common thing around us is cats. Sometimes when you see the "master" at home, they sleep until "rolling eyes", which is likely to see their instarants. Sleeping until rolling eyes

Source 丨 Lorenz Map

Except for cats, animals such as camels, polar bears, and seals have a complete transient membrane. From the analysis of the living environment of these animals, it is clear that their instantaneous membranes can play a certain protective role. In most mammals, the instantaneous membrane has become degraded into trace organs. For example, human transient membranes now can only see a little trace in the inner corner of the eyes, called half -moon fold (BI).

Source 丨 Baidu Encyclopedia

For the knowledge of eyelids, let's introduce it here today. After learning so many knowledge about eyelids, I don't know if you can delay the speed of your eyelids when you are sleepy next time? However, for health considerations, it is recommended that everyone go to bed early and get up early and maintain a healthy schedule in order to not be sleepy at work.

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