1. Harbor Seals: Haul out on shore or hover in the sea to sleep Only haul out on shore to sleep Only hover in the sea to sleep

2. Dolphins: Haul out on shore to sleep Sleep with one eye closed Sleep in a circle

3. Manatees sleep: In cool freshwater rivers Warm tropical seas In warm rivers and the sea

4. Humpback mothers: Carry the babies piggy back while they sleep Tow a sleepy baby with their current Don't know their babies

5. Northern fur seals: Wrap kelp around them while they sleep Curl like jug handles to rock on the tide Rise up and down every four minutes to breathe

6. Beluga whales: Doze peacefully beneath rich, tropical waters Float like white clouds with their blowholes in the air Float like white clouds with their noses in the air

7. Walruses: Stick their tusks into ice flows while they sleep Have air sacs in their necks to hold up their heads Wrap seaweed around them while they sleep

8. Elephant seals: Sleep deep under water Sleep floating on the surface Haul onto land to sleep

9. Sea otters: Wrap kelp around them while they sleep Curl like jug handles to rock on the tide Rise up and down every four minutes to breathe

10. Orcas: Haul onto land to sleep Rise up to breathe about every four minutes Have air sacs in their necks to hold up their heads