Sleeping Dolphins?



Dolphins.  We love watching them frolic in the Gulf of Mexico.  Spend any time on the beach at our Resort and you’re bound to see at least one dolphin gracefully emerge from the water, arc over the water, then dive back down under the Gulf.  You may even see this scene repeated every few hundred yards until the dolphin disappears down shoreline.  No matter how often we see them, we just can’t get enough of our dolphins.

But how much do we know about them?  What do they eat?  Where do they travel?  And the most curious mystery of dolphins, which we’ll unravel today: how do they sleep?  In particular, how do dolphins sleep without drowning?

Dolphins sleep in a way that is completely unlike humans.  They are mammals, just like humans and, as mammals, dolphins need to breathe air to live.  But, unlike humans, who can breathe while totally unconscious and dreaming, a dolphin has to be conscious to breathe.  Its breathing is voluntary. That is, a dolphin has to keep part of its brain awake to remind itself to breathe, even while it is sleeping. 

So, while it is sleeping, only half of a dolphin’s brain will actually shut down.  The other half of its brain stays awake at a low level of alertness and signals when to rise to the surface for a breath of air.  A sleeping dolphin (or a half-sleeping dolphin) will also shut the eye opposite the shut-down part of the brain to watch for predators and obstacles.  After about two hours, the dolphin will reverse the process to rest the active side of the brain and awake the rested half.  This pattern sometimes is called “cat napping”.  Can you imagine being capable of sleeping with one eye open and looking around?  

Where do dolphins sleep? They likely could sleep anywhere, but they probably sleep near the Gulf’s surface.  That allows them to  come up for air easily.  Next time you are on Vanderbilt Beach, look closely at the surface of the Gulf.  You may see dolphins "logging" or swimming slowly along the surface with very little movement.    And if you look even closer, you may think you see those dolphins winking at you.  If so, be very, very quiet!  They may just be taking a nap!

 

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