Dolphins have a fascinating and unique way of sleeping that ensures they stay safe in the water. Unlike humans, dolphins cannot go into a deep sleep because they need to come up to the surface to breathe. Instead, they have developed the ability to shut down one hemisphere of their brain at a time while keeping the other hemisphere active. This process is known as unihemispheric slow-wave sleep.
During this type of sleep, one half of the dolphin's brain remains alert to monitor the environment and control breathing, while the other half rests. This adaptation allows dolphins to stay vigilant against predators and maintain basic bodily functions, demonstrating an extraordinary evolutionary solution to the challenges of living in an aquatic environment.