we were without the internet at the beach for 3 days.
we went to the aquarium and wondered how dolphins sleep knowing that the answer was just a google away:
Dolphins are capable of "unihemispheric slow-wave sleep," which means they sleep with one eye open and one hemisphere of the brain awake. Several times throughout the day and night, a pod of dolphins will sleep with half of their brains and swim in a circle together. The entire group rests the same half of their brains and swims in the same direction. They swim with one eye open and one eye closed. .. they always need to be on the alert for predators or prey...Dolphins are "voluntary breathers" because they need to make a conscious decision to take a breath. If they were to fall asleep completely, they wouldn't be awake to breathe.