BBC News - The myth of the eight-hour sleep:
'via Blog this'
I'll admit that despite having had plenty of experience camping or living outdoors for a month or more at a time in the military, I'd never really given much thought to what life was like before artificial lighting. That and I never suspected that modern sleep habits are a very recent adaptation. Still it makes sense that during periods with more than eight hours of darkness that sleep would be a segmented affair, and that individuals and cultures would fill those periods between first and second sleep with a variety of common practices.
Interesting stuff, and it makes me wonder how our descendants' lives will differ from ours.