I came up with some speculations about the Chauvet cave paintings after watching Werner Herzog's "Cave of Forgotten Dreams".
What the people of 30,000 years ago chose not to paint might suggest the purpose of what is painted on the walls of the cave. Given that most of the Chauvet paintings are highly detailed (lifelike proportions, apparent motion effects, open or closed mouths, etc.), we can see that the artists were very familiar with their subjects -- they were painted from memory. The level of familiarity was high. Humans who lived at the time saw these animals regularly in their lives. It is doubtful that any animal depicted in Chauvet was a rarity.
One subject is notably absent from Chauvet: humans. There is one painting that some people think is half woman, half animal, but it's far from clear. I think the painters would have depicted people, clearly, in addition to animals unless there was a good reason not to. It may have been forbidden. Did they believe a painting could weaken the thing being portrayed? I'm thinking about early photographers and certain native peoples -- some of the natives believed that having their photograph taken would result in their soul being lost or stolen.
If painting an animal made it weaker, it would have been easier to hunt and kill. Hunters may have entered the caves and looked at the paintings just prior to going on a hunting expedition. If the people believed the paintings weakened the represented animals, they might also believe harm would come to people if they were painted.
This would explain why animals are present, but not humans, when humans would seem to be the best subject of all -- you could bring the subject into the cave and paint it beside the real thing, and what artist doesn't want to paint his lover? If the paintings were thought to weaken the real animals, then the artist would have been some kind of priest or shaman, because such beliefs would have been in the realm of the mystical.
Another possibility is that the leader of a group of humans might have commissioned an artist -- perhaps paid in furs, food, weapons or women -- to create a trophy room. The leader was likely the greatest hunter, and what hunter doesn't want a trophy room to show off his prowess? What's a hunter to do in a time before taxidermy? He could collect skulls, I suppose. There is a human foot print in the cave that is probably from a child 8-10 years old. I have to wonder if the chief is showing his son all of the game he has taken down.
There are, of course, all sorts of problems with these speculations. None of the animals are shown dead or with spears embedded. Also, there is an owl.
Whatever the real purpose of the paintings, 99% of the animals chosen for inclusion were the best game a hunter could want. This doesn't seem like a coincidence.
The artist's signature?