Book 11, Question 145
Why Do Some Animals Sleep with Half Their Brain Awake?
Some animals sleep with half their brain awake so they can rest and stay safe at the same time! Dolphins and some birds can do this. One half rests while the other half keeps watch.
More fun facts
- Some animals can sleep with one half of the brain while the other half stays alert.
- Brain recordings show one half in deep slow wave sleep while the other is awake.
- Dolphins can stay alert for at least 15 days in a row this way.
- Scientists first suspected this because dolphins keep one eye closed while resting.
- Seals and some other animals can also sleep with half their brain awake.
Sources: Scientific American, Smithsonian Magazine, National Geographic
Questions kids ask
Why sleep with half a brain?
It lets an animal rest while still staying watchful.