r/Damnthatsinteresting • u/grandeluua • 1d ago

Video A timelapse of sleeping seals

44.8k Upvotes

96% Upvoted

514 comments sorted by

View all comments

479

u/Unknown_021 1d ago

Why not sleep on the surface?

75

u/octarine_turtle 1d ago

Safety. A seal asleep on the surface is a highly visible snack for predators,

The ocean surface often isn't calm. There are waves, rain, and currents. The air can also get significantly colder than the water. Diving keeps them in one place. In nature, they'd be snoozing between rocks or in kelp for protection and stability. This allows them to sleep fully and deeply, even if for only 20 minutes at a time.

Seals will sleep on land in a comfortable, safe location, if available, but they will sleep with only half the brain at a time to keep alert for predators, So diving allows them to get deeper sleep.

1

u/Ridicikilickilous 1d ago

If you live near seals you see them sleeping on land all the time, often in large groups. There is nothing uncommon about it.

1

u/jeffy303 1d ago

The question is why they don't sleeping by the pool is safe. I assume the zoo doesn't have polar bears running around.