If you've not watched the Herzog classic "Cave of Forgotten Dreams" - I highly highly recommend it - the paintings are amazing.
https://en.wikipedia.org/wiki/Cave_of_Forgotten_Dreams
I was recently remembering my son's obsession with trains, buses and dustbin lorries when he was 2 to 5 - a friend tried to explain it as akin the the passion people would have felt for mega-fauna of the past. Did children of the cave-ages obsess over mammoths in the way he did over our local bus?