Sleep with one eye open, truth or fairytale?

As I stated in the introduction, I really like nature. Nature is so relaxing and fun to look at plus the animal’s behaviors are really incredible when you take the time to examine them. Animals are for me the ultimate truth and we should continue to learn from them. Every day plants or animals are disappearing at the surface of the global, we cannot let go those beauties, we have to preserve our nature, our origins. Along my posts on Nature, I will try to tell you a story on something you do not know about Nature 🙂 !


When I was a kid, my dream was to become a scuba diver. I do not know if you know Jean-Yves Cousteau, a famous French naval officer, explorer, filmmaker scientist who studied the sea and all forms of life in water. He truly influenced a whole generation with his submarine documentaries. Every Sunday in from of my TV, it was impossible for me to miss his shows! I was ready for one hour deep dive into the reef corals or other beautiful marine landscapes.


I started scuba diving in 2003 in Martinique les Saintes, one of my best experience! Five years ago, I came across an article which really drove my attention. I was in vacation in Turks & Caicos, in this Bahamas’ island you can see so many shades of blue from the sky to the sea. I was ready to embark for a great week of a scuba diving. While waiting at the scuba diving shop to get my gear, I read an amazing article I never forgot about Dolphins’ sleep behavior.

In fact, the Dolphins sleep with one eye open 🙂 ! How can it be? Well, first you know maybe that our brain (mammals) contain two hemispheres. The right hemisphere and the left hemisphere. Those two hemispheres are linked with a central piece. For us both hemispheres shut down when it is time to sleep. For the Dolphins, it is a different story as they should breath, fight against danger and protect themselves against the cold. The strategy of Dolphins is to « sleep only from one eye »! It is call the unihemispheric slow-wave sleep. In a way, they shut down only one hemisphere of the brain and close the opposite eye. That way the Dolphins can cope with the need of regular air uptake and other duties they have to do while sleeping !

I hope Dolphins will never disappear and one day maybe they can sleep with their two eyes 🙂 !


Alexandre R Rio.

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