Interesting question. It's evident that there was a
good deal of energy expended on these, suggesting perhaps
they had some expendible energy and time to do so.

Some of it does look obsessive and repeatative and might
be the things done to stave off going stir-crazy or
out of boredom. If they were forced to stay in the
caves for some reason: something to do. The interest
in animals is intriguing.

I started searching the web on this topic for two
main questions: in some caves the paintings are out of
reach. How did they reach the ceilings conveniently?

And some are in very cramped crawl spaces. What fashion
of 'fat lamps' were used that could be held while
crawling and also having little soot or fumes
to prevent anoxia or suffocation while crawling
along?