You've got me thinking now. I've been reading that we never used to sleep through the night, but in fact had two sleeps broken by a couple of hours around midnight. It certainly makes sense if you think that in most parts of the world darkness varies seasonally anyway. If you sleep only in darkness hours, then winter would have you sleeping for a lot longer; then surely you'd be sleep deprived in summer.
Most animals will have a larger sleep at night, but general nap whenever the feeling strikes them. If I go into my chickens after dark, while some will be fast asleep, many will be wide awake. Then in the day they'll have times where the huddle in groups to snooze or just randomly doze off, especially in the winter sunshine.
When the weather is hot it's often hard to sleep at night, but easy to doze off in the heat of the day when you feel to drained to do anything anyway. I often wonder why Australians didn't take on the Mediterranean way of up for work early in the summer when it's still cool, siesta in the heat of midday and then work again when it's cooling later in the day. Dinner is often eaten nearer 8pm and then late to bed.
I'm getting ideas now. ;)
I do need less sleep in the long summer days I feel but, the winter days are very short here.
I would think that after hunting and eating, a snooze would be common. Kind of like Christmas every day :)
Blame the English. In my town, they didn't even put verandas on the early houses... I think they were buried young.