Why do fish sleep without closing their eyes, why do fish sleep without closing their eyes

Fish do not have eyelids, so they keep their eyes open. But they also have sleep.

Take a look at the following and you'll understand:

Sleep in fish.

Many people mistakenly believe that fish are animals that don't need to sleep, mainly because of misconceptions. In fact, all vertebrates need rest in order to recover from fatigue in the central nervous system and limbs. As a member of the vertebrates, how can fish be an exception?

They also require sleep rest. So, why do fish give us such an illusion that we don't sleep? We already know that fish, unlike people, does not have real eyelids, therefore.

The fish can't close their eyes whether they are asleep or awake, and even when the fish dies, their eyes are wide open, and they "don't blink to death". In addition, when the fish is resting, it does not need to lie down like other animals, it only needs to be still or slightly swinging in the water.

Some fish sleep in a particularly interesting position. There is a parrotfish that sleeps on the bottom of the sea; Blackfish bury their bodies in the sand and lie on their sides; The river [t] also bends its body to sleep, but it uses water or stones as a backrest. During the day, its body is brown and dark green, but when it sleeps it turns light gray, and its fins and tail are mostly black.

This is because the river [t] sleeps among rocks and aquatic plants, and this posture and the change in body color while sleeping can give itself "cover" against the detection of predators. The fish sleeps alternately by alternating the two cerebral hemispheres, usually always in a state of sleep and the other awake, and every ten minutes, there is a rhythmic alternation. So, on the surface, it looks like it never has to sleep.

Some fish because of the relationship of living environment, can not find a suitable "bed", so can not sleep well, especially in the deep sea or the ocean for long-distance migration of pelagic fish, due to the depth of hundreds of meters to thousands of meters, so that even if the fish want to lie down to rest, but because the pressure is too great, can not settle casually, can only take the method of floating in the water to rest.

Fish float in the water to rest, appropriately stop the activities of various organs, or make a slight movement, which is called "sleep swimming" in fish physiology. The sleeping and swimming of fish varies, and some are in order to defend against the invasion of predators, and often gather into large groups; Others disperse in a certain range of activities, and then regroup at dawn the next day and continue to migrate forward.

This habit of fish is a great inspiration for fishermen. According to the habits of the fish's sleep, the clever fisherman sinks the old tires and wooden boats to the bottom of the sea at the fish-infested places along the coast or near the harbor, creating a quiet "bedroom" that is conducive to the fish's rest, so that the fish "throw themselves into the net" and gather here in groups for round-up. This kind of artificial "hotel" and "guest house" for fish is called "artificial reef" in foreign countries.

Hehe, because fish don't have eyelids!

Why do fish not close their eyes when they sleep? Star Awareness Project

Fish sleep with their eyes open because they have no eyelids and cannot close their eyes when sleeping.

If you look closely at the goldfish you raise, you will find that at night, they will hide in the dark places such as small rockeries and aquatic plants in the fish tank and remain motionless. This is the state of the goldfish when it sleeps. Some fish such as flowers, sea pigfish; They live at the bottom of the ocean, and when night comes, they burrow into the sand and sleep motionlessly.

Some fish, such as the split-billfish and the South Sea parrotfish, will secrete a special gelatinous substance in its body, and when they want to sleep, they blow a big bubble like a child, and the gelatinous bubble hardens when exposed to water, and then they drill into the bubble, leaving only a small hole in the mouth, just like in a sleeping bag. Most of the fish that live in freshwater sleep behind rocks and in the dark of aquatic plants. Like carp and crucian carp burrow into aquatic weeds, while mullet and snapper sleep behind rocks.

Morphology of fish:

1. Spindle type.

Also known as basic (streamlined). It is the body shape of a general fish, suitable for swimming in water, and its entire body is spindle-shaped and slightly flattened. Among the three body axes, the cephaocaudal axis is the longest, followed by the dorsoventral axis, and the left and right axes are the shortest, making the whole body streamlined or slightly flattened.

2. Flat type.

Among the three body axes of this type of fish, the left and right axes are particularly long, and the dorsoventral axis is very short, so that the body shape is flat up and down, and the movement is slow, which is not as flexible as the first two types, and has a benthic life.

3. Stick type.

Also known as eel type. The head-tail axis of this type of fish is particularly long, while the left-right axis and the ventral axis are almost equal and short, giving the whole body a club-like shape.

4. Side-flat type.

Among the three body axes of this type of fish, the left and right axes are the shortest, and the proportion of the head-tail axis and the dorsal and ventral axes is about the same, forming a symmetrical flat shape on the left and right sides, making the whole body shape appear flat and wide.

The above content reference: Encyclopedia - Fish.

1. Why don't fish close their eyes when they sleep?

Answer: That's because the fish doesn't have eyelids on the outside of their eyes and can't close their eyes. Therefore, whether the fish is asleep, awake, or even dead, its eyes are still wide open.

2. Why do elephants like to bathe in mud?

Answer: That's because elephants don't have sweat glands and sebaceous glands, and when the water in the mud evaporates, it's like sweating, which cools the elephant and repels parasites from its body.

3. Why do fireflies emit light?

Answer: The glowworm glows with a luminaire on its tail, which contains luciferin and luciferase luminescent substances. When the air enters the luminaire, the fluorescein is catalyzed by luciferase, and the oxygen in the air is combined to produce fluorescence in the energy conversion.

It can be seen that fireflies do not shine at night, but this light is not as bright as sunlight, so they think that they do not shine during the day.

4. Is it going to rain if the swallow flies low?

Answer: Because whenever heavy rain comes, the clouds in the sky are lowered, and the air pressure also drops, and it is difficult for insects to fly at high altitudes, so they can only fly at low altitudes, and swallows have to fly close to the ground in order to prey on insects. So the swallow flying low is indeed a sign that it is about to rain.

5. Why don't fish freeze to death under frozen water?

Answer: In winter, the water on the surface of the river freezes, but the water under the river does not freeze, and the temperature remains around 4 degrees Celsius, so the fish will not freeze to death.

6. Why do ants line up to carry things?

Answer: Ants line up to carry things because when they walk, they emit a gas that only their own kind can smell. The ants walking behind smelled this smell and followed the ants in front of them and automatically lined up.

Fish are vertebrates, need to sleep to eliminate the fatigue of the nervous system and limbs, but the fish has no eyelids, it can't close its eyes when sleeping, it sometimes sleeps in the dark, sometimes it sleeps in the sand or secreted bubbles to sleep, sometimes it swims while sleeping, all kinds of different postures, just live freely.

Fish sleep, but they sleep with their eyes open.

Fish also need to sleep to relieve stress and maintain physical balance. It's just that the fish sleep with their eyes open, so people have the illusion that they can't sleep.

Fish sleep with their eyes open because they don't have eyelids and can't close their eyes when they sleep. It hides in the dark and sleeps, and it sleeps motionless. Some fish will burrow into the sand when they sleep, which is quiet and can prevent damage from natural predators; Others secrete bubbles when they sleep, and then burrow into bubbles, like sleeping bags; Others swim while sleeping.

The sleep time of fish is very short, the total sleep time is generally only 2 3 hours a day, and the sleep time is not fixed, or it is done in multiple times. In the case of carp, crucian carp and goldfish, for example, they may have to sleep more than a dozen times a day, and each time they sleep for about 20 to 30 minutes, which is too short for us humans.

Sleeping characteristics

1. Sleeping in the dark: When many fish sleep, in order to avoid the attack of natural enemies, they will generally hide in the dark, such as carp, crucian carp, mullet, snapper, etc. Usually carp and crucian carp hide in aquatic plants to rest, while mullet and snapper sleep behind rocks.

2. Sleeping in the sand: Some benthic fish, such as flower sea pigfish, golden carp and micro-humphead fish, usually move underwater, and will hide in the sand when sleeping. In this way, other predatory fish are avoided from being eaten.

3. Secrete bubbles: In addition to the fish that sleep with the help of natural rock bodies, there are also some fish that can create a safe bubble by themselves, such as split-billfish and South Sea parrotfish, etc., ** can secrete gelatin, which will become hard after encountering water, and drill into the bubble to rest, leaving only a small hole, so that it can also breathe.

4. Swimming and sleeping: There are also some fish with a relatively high metabolism, they must swim all the time to be alive, so they will not stop when sleeping, such as sharks, mackerel and tuna, etc., making it difficult to tell whether they are sleeping or awake.

Fish are vertebrates, need to sleep to eliminate the fatigue of the nervous system and limbs, but the fish has no eyelids, it can't close its eyes when sleeping, it sometimes sleeps in the dark, sometimes it sleeps in the sand or secreted bubbles to sleep, sometimes it swims while sleeping, all kinds of different postures, just live freely.

Fish sleep with their eyes closed to protect their eyes. Unlike humans, fish do not have eyelids to protect them, so while sleeping, they need to protect their eyes to avoid injury. In addition, sleeping with eyes closed can also help the fish relax their bodies and fall into a deeper sleep state, so as to better recover their strength and energy.

At the same time, the fish can also perceive their surroundings through other senses while sleeping, so that they can quickly escape danger when needed.

Fish also sleep, but because fish do not have eyelids, they do not close their eyes when they sleep. Most fish remain motionless in the water when they sleep, and they sleep for a short period of time. A small number of fish sleep during exercise, but it swims very slowly.

Fish also sleep, but because the fish does not have eyelids, it will not close its eyes when it sleeps, but will stay in a darkly lit place to rest.

That's because fish don't have eyelids, they can't close their eyes when they sleep, sometimes they sleep in the dark, sometimes they sleep in the sand or secreted bubbles, and sometimes they swim while sleeping, and they laugh in a variety of different ways.

Vertebrates have to sleep, fish are vertebrates, they also need to sleep, in order to eliminate the fatigue of the nervous system and limbs, it is common to see the fish standing still in the water, the gills are flashing and moving, this is exactly the fish sleeping, if it is awakened, it will swim in the water again.