> but is also based on predators who prefer to catch prey asleep While it's true, that's why most people in ye olde times would awake about 1 am (gone to bed a

> but is also based on predators who prefer to catch prey asleep While it's true, that's why most people in ye olde times would awake about 1 am (gone to bed at 8 pm) have a snack and go back to bed. Additionally there was also after snack siesta (we had those on Sunday afternoon). In primeval times, having a brief pause relaxing in the tree after lunch seems like good way to prime you for sleep later in the evenings. Sleep isn't a luxury, it's a necessity, necessary for our brains to defrag. Saying sleep is luxury is like saying eating isn't a necessity for survival. As someone that at one point did trade day and night, I can tell you I was plagued by heart palpatations and general feeling of unease even after switching to 8hrs of sleep during day.