How do dolphins sleep without drowning? [video] | Hacker News Reader

How do dolphins sleep without drowning? [video]

smithsonianmag.com

63 pointsdeepakjc18 comments

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

Some migrating birds use this strategy also.

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

If you venture to a local pond/lake and observe the mallards and black ducks, some of them have one of their eyes open while sleeping because they can keep half of their brain awake. I just happened to notice it while on a daily walk and had to go look it up afterwards. Ducks also make outrageously loud quacks when alarmed (sounding similar to a single person laughing too hard at an unfunny joke). Made me jump more than once when walking after dark.

Not all of them will always sleep with one eye open, but at least a few in a group will in order to keep watch from coyotes, birds of prey and stray cats when they're not in the water.

Heads up: video with sound auto-plays.

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

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

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.

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

I know first hand someone who have driven several kilometres only to "wake up" and not being able to explain. This is of course extremely dangerous and in every case I know of it has ended with a damaged / wrecked car though luckily no injuries or fatalities. (Back country roads, middle of the night etc).

What happened in at least one of these cases was dreaming with eyes open. From what I hear that might not be to uncommon but here I'm back to old wives tales.

There is a case to be made with these situations that you weren't actually asleep.. you just didn't lay down memories for the period of time, because nothing happened.

You feel like time is missing because you have no recollection of that time - but that does not have to equate to you not being awake, or able to respond.

My college roommate slept with his eyes open. Creepy as fuck.

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

Right brain asleep while you're programming and left brain asleep while you're designing! You could literally never stop working! ;)

You'll end up making code that works well but looks like crap, and beautiful designs that have zero use in the real world ;).

But good luck doing either of those with only one hand.

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

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.

Giraffe sleeps in 10-15 min increments.

Very interesting!

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