What happens inside a dolphin’s head when it sleeps? Half its
brain goes to sleep! That means the dolphin is half asleep and half awake. The
dolphin is not fully asleep. Its sleep is incomplete.
The kind of sleep is not perfect for people. It is imperfect.
But incomplete sleep is perfect for dolphins. When dolphins are still, or
immobile, incomplete sleep lets them know when to breathe. Incomplete sleep
also lets dolphins sleep with one eye open. Then dolphins can escape from
danger!
Activities:
1. How do dolphins sleep? Why is incomplete sleep perfect for
dolphins? Discuss with your partners in simple English.
2. To learn more about dolphins’ sleep, watch the video:
