Sharks' Sleep

Sharks' Sleep


Sharks never stop moving even when they sleep or rest.


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Shark species that need to swim constantly to keep water moving over their gills seem to have active periods and restful periods, rather than undergoing deep sleep as we do. They seem to be "sleep swimming" with parts of their brain being less active, or "resting" while the shark remains swimming.

At least one study has indicated that the shark's spinal cord, rather than the brain, coordinates swimming movements. This would make it possible for sharks to swim while they are essentially unconscious (fulfilling the suspending consciousness part of the dictionary definition), thus also resting their brain.


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