6 ms·

How do dolphins sleep without drowning? [video]

63 points by deepakjc 12y ago

deepakjc 12y ago
Pretty surprising answer, they sleep half their brain at a time!
- lutusp 12y ago
  Some migrating birds use this strategy also. http://en.wikipedia.org/wiki/Unihemispheric_slow-wave_sleep http://en.wikipedia.org/wiki/Unihemispheric_slow-wave_sleep
  - yareally 12y ago
    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.
mholt 12y ago
Heads up: video with sound auto-plays. Here's a direct link to bypass the advertisement: http://www.smithsonianmag.com/videos/category/ask-smithsonian/ask-smithsonian-how-do-dolphins-sleep-witho/?no-ist http://www.smithsonianmag.com/videos/category/ask-smithsonia...
140am 12y ago
Interesting - i know a few people who seem todo that throughout the day
darklrd 12y ago
Very interesting!
lightblade 12y ago
I wonder if human can be trained to do this. Certainly sounds like something coming out of sci-fi or martial art movie.
- lukeholder 12y ago
  I have heard of Cowboys sleeping with eyes open, but not sure if thats just a old wives tale.
  - reitanqild 12y ago
    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.
    - dedward 12y ago
      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.
  - grayclhn 12y ago
    My college roommate slept with his eyes open. Creepy as fuck.
- painflop 12y ago
  Full-day working hours? Programmer by day, designer by night!
  - kethinov 12y ago
heroku 12y ago
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 12y ago
Giraffe sleeps in 10-15 min increments.

63 points by deepakjc 12y ago

deepakjc 12y ago

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

lutusp 12y ago
Some migrating birds use this strategy also. http://en.wikipedia.org/wiki/Unihemispheric_slow-wave_sleep http://en.wikipedia.org/wiki/Unihemispheric_slow-wave_sleep
- yareally 12y ago
  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.

mholt 12y ago

Heads up: video with sound auto-plays. Here's a direct link to bypass the advertisement: http://www.smithsonianmag.com/videos/category/ask-smithsonian/ask-smithsonian-how-do-dolphins-sleep-witho/?no-ist http://www.smithsonianmag.com/videos/category/ask-smithsonia...

140am 12y ago

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

darklrd 12y ago

Very interesting!

lightblade 12y ago

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

lukeholder 12y ago
I have heard of Cowboys sleeping with eyes open, but not sure if thats just a old wives tale.
- reitanqild 12y ago
  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.
  - dedward 12y ago
    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.
- grayclhn 12y ago
  My college roommate slept with his eyes open. Creepy as fuck.
painflop 12y ago
Full-day working hours? Programmer by day, designer by night!
- kethinov 12y ago

heroku 12y ago

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 12y ago

Giraffe sleeps in 10-15 min increments.