There's a book ‘Shaman’ by Kim Stanley Robinson, who's said to do a lot of research for his writing. In one scene of the book, a man goes into a cave to paint s

There's a book ‘Shaman’ by Kim Stanley Robinson, who's said to do a lot of research for his writing. In one scene of the book, a man goes into a cave to paint such images. Well, when his fires go out, he then spends three days groping around for the exit in complete darkness and getting weaker from hunger, until people from the tribe come in search of him. Meanwhile I imagined real caves as mostly ’in and out’ kind of thing: out of light sure, but not three days worth of crawling.