How the fish sleeps. Features of the holiday

Many animals in nature and at home rest in different ways. Some are standing, some are lying or sitting asleep, some are afloat. So, for example, did you think about how the fish sleeps? This cold-blooded also needs rest, even a short-term one. An interesting question, you must agree, because no one has ever watched fish with closed eyes. Why? Because they have no age, and they simply can not close them!

Ground animals are forced to moisturize, constantly blinking, the eye surface. And in a dream it is rather difficult to carry out, as the control over reactions is lost. Therefore, the eyes of mammals, for example, are closed during sleep for centuries. Fish have another story: they exist in water, so moistening the eyeball is not always necessary. But still they, like all animals, have to rest. About how the fish sleeps, we will tell in our article. And these representatives of the world of fauna are sleeping in different ways, which depends on the species and habitat.

How the fish sleeps

It is known that fish do not rest like they do, for example, mammals (well, by the way, to study the behavior of these animals to those who have an aquarium). The sleep of fish, rather, resembles a phase of rest, relaxation, when many functions of the body slow down, and the reaction is weakened. Some species of fish so turn off their reactions, that they can literally touch with their hands and shine a flashlight in the eye - they still remain immobilized. Some species, on the contrary, can feel danger in this state.

Where do fish sleep

During their rest many kinds of these cold-blooded become practically immobile. They, as a rule, rest on the bottom territory. This applies to many large river and lake species. But the assertion that every fish is asleep on the bottom will not be completely correct. Some oceanic fish species must constantly be in motion, even during sleep. These include, for example, sharks and tunas. Water must constantly pass through their gills, otherwise they may suffocate. Therefore, the tuna fall on the water against the current and, thus, swimming, rest. And sharks - these contemporaries of dinosaurs - and do not have a bubble, which is available in other species of fish. This fact is one more argument to be in motion even during the rest. After all, otherwise the shark will simply sink to the bottom and, after all, no matter how funny it sounds, it will drown! And also - skates and sharks do not have lids on the gills, like many bone fishes, so the water goes there only at the time when the fish moves, and to sleep relatively calmly, as bone does, they do not work - it is necessary all the time Somewhere to swim.

Features of rest

The position in which the fish sleep is largely dependent on the species. For example, the astronotus hangs upside down. A fish-clown on the bottom of the aquarium is stacked on its side. Some aquarium fish just hang in stillness.

How does the fish sleep? In natural conditions, the conditions for her rest can also be very different. Flounder is digging into the sandy bottom at the bottom. Cod sleeps lying down. Herring - and at all upward belly, rafting downstream. Most of the benthic fish sleep in secluded places, previously prepared among stones and crevices, corals and algae. A parrot fish envelops itself with a cocoon of mucus to become invisible to a predator.

Duration

How many fish are sleeping? Most fish, like many animals, are active throughout the daylight hours. With the onset of darkness, life stops, it's time to rest. Therefore, for example, it is so important for fish contained in aquaria, the reasonable observance of their natural regimen. Agree, if you wake up at three o'clock in the morning with bright light and noise, you are unlikely to like it. So for fish: you need to turn off the artificial lighting of the aquarium in the evening and at night, so that animals can rest. Otherwise, the life expectancy of aquarium fish can be significantly reduced.

Night hunters and not sleeping

It is characteristic that some river predatory fish (for example, catfish or burbot) do not sleep at night. They prefer to hunt, and in the daytime - to rest. However, among the fish, leading the daily way of life, come across those who like to arrange a day of the siesta. But dolphins (mammals, which were previously ranked as fish) do not sleep at all! Hemispheres - left and right - the dolphin's brain rest in turns (each about 6 hours). The rest of the time the two hemispheres are awake.