It is often said that sharks can never stop swimming, is that true? Do they have to sleep while swimming? Or is it that sharks do not sleep as we understand the act of sleeping? How do sharks sleep?
In this article on our site we will answer all these questions to explain how sharks sleep We will provide some curiosities and relevant data about resting of a shark to learn a little more about the lifestyle of this magnificent animal. Do you want to know more about these fascinating creatures? Well, stay and read this interesting article about them!
Do sharks sleep, yes or no?
Before denying or affirming any data on the rest of sharks, it should be noted that there are more than 400 species of shark, each one of them being unique and different from the others. For this reason, we can speak of generalities, but bearing in mind that each species is a world apart, although they have things in common with each other. That said, do sharks sleep? Yes and no, that is, sharks sleep, but they do it in a different way from other fish and that can be defined more as "rest" than as " sleep", taking into account our perception of sleep. All living things need sleep to live, in one way or another, and sharks are no exception.
Do sharks sleep with their eyes open?
As for whether sharks sleep with their eyes open, this is completely true, because no species of shark closes its eyes, rest as each one rests. Basically, sharks couldn't sleep with their eyes closed because they don't have eyelids, so logically they can't close their eyes like we do, for example. These animals only have a thin translucent membrane, but this only closes when they hunt their prey, not while resting.
Do sharks rest?
Sharks do not sleep like the vast majority of animals, for this reason they have come to be thought of as part of the animals that do not sleep. However, as we have anticipated, living beings need to sleep, in one way or another. This brings us to another question: Do sharks rest? Of course! They need rest to recover from the wear and tear of swimming and foraging.
How do sharks sleep?
There are different species of shark, as we have already mentioned, and in terms of how they rest, two types can be distinguished The first It is made up of those sharks that, in order to obtain oxygen and be able to breathe, must be moving the water while they move, only in this way does the oxygen enter their gills. In these first ones, the rest is done while they swim, they can afford this because they do not sleep as such, but leave part of their brain inactive, resting or sleeping. Marine biologists have found that swimming motion is not controlled in the brain, but in the spinal cord of sharks. Therefore, they can disable different parts of the brain and still continue swimming. This group is capable of non-stop swimming, alternating periods of total consciousness with semi-consciousness or almost total unconsciousness. Within this group we find the white shark, for example. So if you're wondering how great white sharks sleep, here's the answer.
The second type of shark is the one that has a mechanism to obtain oxygen without having to constantly swim. This can be done thanks to the fact that they present structures called spiracles. For this reason, these sharks rest immobile on the seabed, so their daily energy expenditure can be significantly reduced compared to the first group.
Does the shark never stop swimming?
As we have already mentioned, the group of sharks that lack spiracles, those structures that would allow them to obtain oxygen without having to be constantly in motion, never stop swimming. For this reason, sharks that do not have this mechanism must always be moving, with their mouths and gills open so that oxygen can enter their bodies.
On the other hand, the group of sharks that does have a blowhole can afford to stop at nothing. However, none of the different types of sharks have swim bladders, so they cannot float if they are standing still. Therefore, those sharks with spiracles have to go down to the seabed to rest, because they cannot stay off the ground if they do not swim.
