"Apparently, prior to the 18th Century, us humans used to split our night’s rest into two phases. One started shortly after dusk and ended at midnight, and we followed it with another that began at 2 a.m. and ended just after daybreak. (...) historians have surmised that people indeed slept in two phases, and spent the middle bit of the night essentially having a blast."
Entry n. 9.944 on the list of things capitalism took away from us.
https://www.popsci.com/weirdest-thing-mole-rat-baby-shark-second-sleep