How do dolphins sleep without drowning? [video]

[deepakjc]

Pretty surprising answer, they sleep half their brain at a time!

[lutusp]

Some migrating birds use this strategy also.

http://en.wikipedia.org/wiki/Unihemispheric_slow-wave_sleep

[mholt]

Heads up: video with sound auto-plays.

Here's a direct link to bypass the advertisement: http://www.smithsonianmag.com/videos/category/ask-smithsonia...

[lightblade]

I wonder if human can be trained to do this. Certainly sounds like something coming out of sci-fi or martial art movie.

[kethinov]

No, we lack the ability.

Any animal without big selection pressures to develop and maintain this ability seems to lose it rapidly, as other adaptations of the brain for other purposes seem to preclude USWS. Only animals which really need it seem to have it.

[lukeholder]

I have heard of Cowboys sleeping with eyes open, but not sure if thats just a old wives tale.

[painflop]

Full-day working hours? Programmer by day, designer by night!

[140am]

Interesting - i know a few people who seem todo that throughout the day

[heroku]

wait a sec, do they sleep 8 hours total, or 8 hours per side. Because if they sleep 8 hours that makes it only 4 hours.

[lukasm]

Giraffe sleeps in 10-15 min increments.

[darklrd]

Very interesting!