Do jellyfish sleep? They don't have brains. Googled it. Yes, they do.
Theory is that during sleep, mammals review and process what happened while it was awake and physically recuperate. Can die due to sleep deprivation.
But what about cells, most do not sleep.
Probably many reasons for sleeping? Makes sense.
Good practice for dying in sleep? Just didn't wake up one day.
Collective consciousness and sleep? Maybe?
