Dolphins Turn Off Half Their Brains to Sleep
As oxygen-dependent mammals that reside in water and voluntarily control their breathing, dolphins simply cannot let themselves slip into a state of complete unconsciousness. As a result, they experience what’s known as unihemispheric slow-wave sleep, in which only half the brain sleeps at a time and the other remains awake at a low level of alertness.
Dolphins typically float motionless or swim slowly near the water’s surface when in this state, with the eye opposite the resting side of the brain remaining closed. And while people and dolphins have very different slumbering habits, dolphins typically get about four hours of slow-wave sleep for each side of the brain in a 24-hour period, which matches up with the doctor-recommended eight hours of shut-eye per night for humans.
Read more on the next page...