Does anyone else wonder if this might have been a genetically evolved skill for tribal societies? As in, an “outgoing” subset of the tribe hunted all day, returning to camp exhausted and ready for a full night’s sleep, while another subset found themselves activated and ready to keep vigil overnight (or some 1st watch staying up, others waking super early for last watch)? Like maybe having different mindsets like this kept the tribe healthy and protected. Safe from overnight surprise raids by rival tribes thanks to these night watchers and those traits continued being passed on among a subset of descendants as a successful adaptation.