Sharks are creatures that don’t sleep. They change their activity level throughout the day, cycling between an active state and a restful state. In the restful state, they slow down or halt their swimming to conserve energy, but they do not close their eyes and slip into a sleep-like state.
Some shark species appear to have a sleep-like period of inactivity while also setting at the bottom of the ocean. This behavior is known as “bottoming” or “sitting on the bottom.” Sharks that engage in this behavior often rest with their eyes open, and they are all the while vigilant to potential threats or food sources.
Why Can’t Sharks Sleep?
Sharks don’t have eyelids, so they can’t completely close their eyes when entering this altered state. And since they are not able to close their eyes, scientists believe that sharks do not sleep in the same way humans and other animals do.
How Do Sharks Rest?
Sharks rest in various ways, depending on their species. Sharks rest in two ways: by stationary swimming and by resting on the ocean floor. These two methods of resting are dependent on how the sharks gather oxygen when they rest.
Some sharks gather oxygen through their ram ventilation. These sharks need to have oxygen-rich water constantly rammed against their gills, which can be obtained through swimming; otherwise, they’ll drown. This is why these sharks appear idly swimming when they’re resting
Sharks that rest on the ocean floor catch oxygen through buccal pumping. They use their cheeks that will pump water toward their gills, which allows them to stop moving and not drown
Conclusion
So, even though sharks don’t sleep as humans do, they still need to rest. Sharks use both stationary swimming and resting on the ocean floor to get the necessary rest that their bodies need. It is important to note that when sharks enter these altered states of activity or inactivity, they are still able to respond quickly to potential threats or food sources. Therefore, even though sharks don’t sleep, they still have ways to give their bodies the rest they need to survive.
