Ocean field note
One eye on watch
The Dolphin's Half-Awake Sleep
A dolphin sleeps with only half of its brain at a time, keeping one eye open to watch for danger.
Let's look closer
How can you sleep and stay alert at the same time?
ecause dolphins are mammals that must rise to the surface to breathe air, and can't afford to lose consciousness completely while swimming, they rest one half of their brain at a time while the other half stays awake, trading off through the day and night. The open eye, connected to the alert half of the brain, keeps watch for predators or obstacles and helps the dolphin remember to surface regularly for air. Meanwhile its partner half, and the opposite eye, rest quietly, until the two halves eventually swap roles.
Look for this
Explorer clue
In a calm bay at dusk, look for a dolphin resting near the surface, moving slowly and breathing steadily rather than leaping and playing.
Your turn to wonder
Curiosity question
If half of you could always stay watchful while the other half rested, what would you want it to watch for?
Keep wandering
