If I had been there I would have been drawing on the walls of the cave and I am female!
As would have I! And my daughter. But not my son. I don't think this theory is too much of a stretch. Just take a walk through your local Hobby Lobby and see toward whom most of the merch is aimed. Girls are crafty.
As a little girl I would spend hours and hours drawing and coloring...wait for it...HORSES! Who doesn't know of at least one or two little girls who has gone through an obsessive horse drawing phase of life? Not to mention kitties and doggies, etc. I'm telling you it's as much a compulsion for girls as trucks or banging things with sticks are for boys. And since the girls and women were pretty much holed up in those caves for months I would not be the least bit surprised if they filled them up with pretty animals (and fantastical pictorial descriptions of brave hunters among them..think prehistoric Tiger Beat! Ha! Or maybe the hunting scenes happened when a pesky brother or bully kid wanted to make a girl cry, so he "shot" the pretty animals with a crappy stick figure hunter.)
What? "It could happen!"