How Do Sharks Sleep?
Growing up, we believe that sharks are sea creatures that never sleep as they need to keep moving to survive. They need to keep water moving over their gills to receive oxygen. Yes, they are engaged in rest periods all day, but it is different from the kind of sleep like other animals do. Does this mean sharks never stop; therefore, they should not sleep?
While shark species sleep, most of them don’t sleep the same way humans do. Though they have alternating periods of profound rest and alert wakefulness similar to sleep, others never sleep at all or never close their eyes. So, how do sharks sleep? In this blog, you will find answers to this question. You will also understand why sharks are like that and why they live that way.
Do Sharks Sleep?
This question varies on how you understand sleep. Based on the Merriam-Webster dictionary, sleep means; “a natural suspension of consciousness while the powers of the body return.” However, we are not sure if they can suspend their consciousness when it comes to sharks, though it may be possible.
So, do sharks rest for several hours as humans do? Well, that’s not likely. They need to swim more often to always keep the water moving over their gills to have restful and active periods – rather than deep sleep. It’s like sleep swimming, where some parts of their brain are less active or just resting while their body remains swimming.
There is also one study that shows that the spinal cord organizes swimming movements more than the brain. So, it would make it possible for them to swim while they are unconscious. It fulfills that suspension of consciousness, thus resting their brains.
What are the Types of Sharks that Sleep?
Before you know how sharks sleep, perhaps you should also know what are the sharks that sleep. Some sharks are found in the oceanic regions of the open seas. They are far from the shore but not really near the bottom. They swim all the time and don’t sleep, and if a fishing net catches them, they may experience a lack of oxygen or hypoxia, and worse, they could drown.
So, now you understand how sharks sleep. This time, you should also know the types of sharks that sleep, called Ram Ventilators. It describes how sharks would inhale through their mouth opening and ram water backwards through their gills. Below are the examples of obligate ram ventilation sharks:
Great White Sharks
The sleeping pattern of Great White Sharks have puzzled scientists for years. However, during the course of deviation from old sharks to modern, the spiracles of great white sharks have become small to non-existing at all. Because of this, great white sharks are thought out as obligate ram ventilators. It means they need to keep moving to move the water over their gills and to breathe.
Whale Sharks are one of the obligate ram ventilation sharks. It means that they need to stay within the water to get enough oxygen through their gills. Some studies indicate that the whale shark’s spinal cord causes them to swim and not their brain.
It is also believed that the brain of some whale sharks will keep them moving, so they will experience a less active period. It’s a period of rest. However, whale sharks can’t sleep like humans.
There is oxygen-rich water that flows through the gills of Mako Sharks when they move. This will allow them to breathe. Other Mako sharks have spiracles that will force the water across their gills and allow them to have a stationary rest.
Usually, sharks that live at the bottom of a deep and shallow ocean will stop moving and remain at rest. They sleep on coral reefs or sandy sea bottom, and when they’re awake and moving, they will ventilate. However, when they need deep rest, they swim or sink to the bottom where they sleep.
What are Sharks Doing When they are not Sleeping?
Now that you understand how sharks sleep, it’s also great to know what they are doing when not sleeping. Most sharks spend their time eating and cruising calmly. However, almost all of them are carnivores, and they usually chew on fish.
They rarely attack humans, and when they attack, it is usually because of mistaken identity. Surfers must be aware of this, as they are those humans that get shark bites. Mainly because they look inviting to sharks or they look like sea turtles.
Will Sharks Die if they Stop Moving?
Well, the answer is somewhat true, but it could also be false. For example, there are more than 400 shark species in the ocean. Some of these species may need to move all the time to keep the water moving on their gills so they can breathe.
Some also have structures to allow them to breathe while lying on the bottom of the ocean. They have this spiracle that is small and opens behind each of their eyes. It forces water across the shark’s gills so they can be still when they rest. This is handy for bottom-dwelling sharks like skates and rays.
Asleep or awake, sharks are an important part of the ocean. Despite their doubtful reputation as savage killers, most of them don’t harm humans. The truth is, humans are far more dangerous than shark species are to humans. Yes, sharks may kill thousands of people, but humans may kill tens of millions of sharks every year. And how do humans do that? Simply by not taking care of the ocean.
By the time you’re done reading this article, hopefully, you will realize that one of the factors that help sharks survive is in the hands of people like us. The more you understand about sharks, not only understanding how sharks sleep, the less you are likely to get scared of them. It will make you realize that they are important, much more appreciating them as they also play an important role in our survival.
And you can simply show your appreciation with the Ocean including the sharks just by wearing our ATOLEA Shark-inspired jewelry collections. Not only that our designs will make your outfit stand out more, you are also helping us continue our mission of giving back to the Ocean. Part of your purchase goes to Ocean conservation charities aiming to preserve the Ocean and marine life.
So dive into our ATOLEA Shark Jewelry collections now and wear your love to the Ocean!