So, in order to sleep, whales and dolphins will engage in what is referred to as hemispheric sleep, where they shut down only half of the brain, and close the opposite eye.
We don't need a bunch of nonsense clogging up the comment threads.
While half of the killer whale's brain catches up on sleep, the other half controls the breathing.
Some dolphins sleep for roughly 33% of the day, while the larger sperm whale is thought to sleep for only 7% of the day! Whales, as we have mentioned earlier, sleep with a part of their brain active and an eye open.
Posted by 3 years ago.
It was not until the boat accidentally nudged one of the sperm whales that they noticed the presence of the boat.