In 2001, historian Roger Ekirch of Virginia Tech published a seminal paper, drawn from 16 years of research, revealing a wealth of historical evidence that humans used to sleep in two distinct chunks.
His book At Day's Close: Night in Times Past, published four years later, unearths more than 500 references to a segmented sleeping pattern - in diaries, court records, medical books and literature, from Homer's Odyssey to an anthropological account of modern tribes in Nigeria.
Much like the experience of Wehr's subjects, these references describe a first sleep which began about two hours after dusk, followed by waking period of one or two hours and then a second sleep.
I’ve not read the book yet (not till March at the earliest—too busy). I’d think camping experiences wouldn’t tell you much, because we have the habits of the rest of the year to guide us. But what with going to bed early and overly wobbly air mattresses, I frequently do find myself waking up in the night.
And we all know the 3am wakeup. You can't get back to sleep for an hour, or maybe two.
I was perhaps too young to wake up easily at the time, but we lived only a few hundred yards from an African village for a time. I remember roosters crowing at all hours of the night (not just in the morning), and some loud celebrations that went on until whenever, but I don’t remember any other middle-of-the-night noises. Without electricity they didn’t stay up watching TV or listening to the radio much. On the other hand, wandering about at night when you can't see the snakes easily is contra-indicated, so maybe they stayed quietly at home.
It is already too late for me to go to bed early to test it out...