Did you know that our beloved animals, dolphins, sleep having one eye open due to their incapability of breathing in the water for a long time?
Dolphins can’ t hold their breath more than 15-17 minutes, so they sleep by resting one half of the brain each time. This is called ‘unihemispheric sleep’.
During this time the eye opposite the sleeping half of the brain is open, while the other is closed.
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