I had one of the best sleeps of my life on a bed of soft sand, in the curve of a dry creek that I really should not have slept in due to flash flood risk. Since then I've wondered if ancient people might have made mattresses of sand, but they were so simple and evanescent that they left no trace.
Accounts by westerners enslaved by nomadic tribes (when they shipwrecked on the coast) often talk about looking for sand to sleep on, especially when in the rocky parts of the Sahara, so I’d wager humans have been sleeping on sand for a very long time.
The kalahari bushman had a trick to stay cool on a hot day: dig a sand pit in the shade, put in the fibrous bits of inedible plant material, pee on them, lay down in the pit and cover up with sand and wait until the evening cooled things down.
Not even a ground cloth, just a sleeping bag. Under an astonishingly clear night sky with galaxies for nightlights. This was the territory of the red diamond rattlesnake and the Arizona giant hairy scorpion. If they visited me that night I was too sound asleep to notice.
