Ducks Can Sleep With Half Their Brain Awake
Ducks have a special ability called unihemispheric slow-wave sleep. One half of their brain rests while the other half stays alert to watch for danger. This lets them keep one eye open and stay safe while still getting needed rest.
💡 Fun detail:
The duck watching for predators can even switch which side of the brain is sleeping if the threat moves to the other side.
Source: National Geographic