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Comment by 1970-01-01 | Hacker News Reader

1970-01-01

I'm not a neuroscientist, but it's hard to understand why anyone thinks that this mandatory downtime for all animals is just for a special reason. Why wouldn't sleeping be a catch-all window for autonomous maintenance and overall survival? Always take the most likely reason.

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It seems that given the options of 1) staying awake and active as normal during the night and 2) using the night period to run various maintenance task but without awareness the second option apparently turned out to be the winner as far as evolution is concerned.

What's interesting to me is how many animals beyond humans do it - so it's not purely tied to the human cognitive functions like higher order thinking etc.

Plenty of animals are nocturnal, diurnal, or sleep in non-24h windows. Evolution does whatever works.

I think part of the answer is that our world is just very conducive to hidey-holes. There isn't that much surface area you need to cover in a three-dimensional space to get protection from the elements and other predation, and there's an awful lot of stuff out there (trees, dirt, etc) you could comfortably use to do it.

3) Some animals can sleep with only half their brain at a time.

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

Isn’t that the crux of the question? Figuring out what all the maintenance stuff our bodies need to do every night and how it works seems useful

And whether we can recreate it without sleep.

The way dolphins sleep with half of their brain asleep is fascinating to me.

https://us.whales.org/whales-dolphins/how-do-dolphins-sleep/

Also some birds, even while flying.

Actually makes sense - like CPU that deactivates extra cores to let them cool down.

Depends how you look at it, but fatal things should have a clear explanation for why they kill you. We can survive longer without food and that one is easy to explain.

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