Prehistoric people leaving things in caves is practically the only way we still know about them, but that doesn’t mean humans normally hung out in caves as a permanent lifestyle. We have evidence of people making wooden structures in Africa long before the first cave paintings—and compared to structures, caves would have been cold and dark, unlikely to be conveniently located, and contested for by cave-adapted animals.

It’s because the caves were so shitty that subsequent people left them untouched for tens of thousands of years.