Jessa Gamble expounds on the many variations:
Solitary sleep on a softly cushioned surface, between four walls and under a roof—it’s hardly typical. Anthropologist Carol Worthman has spent many years in the field studying nighttime in traditional societies. In contrast with the Western sleep model—a regular bedtime followed by continuous sleep until morning—the Eje of Congo have some level of social activity persisting through all hours. The sleeping area of a family will see coming and going as some members retire, grooming each other for parasites that might disturb their sleep, and others hear the familiar strains of a thumb piano and get up to dance.
Botswana’s !Kung have similarly staggered bedtimes in their two-metre-round huts made of sticks and leaves. The huts aren’t much of an insulator for heat, sound, or predators—they mostly just keep the rain off—and it’s easy to feel embedded in the social interaction outside the hut. This setup lends itself to a less defined difference between sleeping and waking. Adults and children alike stay up as long as something interesting is going on, and it’s perfectly acceptable to check out of a group conversation by going to sleep.
The Dish 