There was a TV series about the origins of Art recently that featured this shamanistic explanation. The first cave drawings were apparently made by the first acid-heads recording their trips on psychotropic drugs. The hypothesis is that the shamans were painting their 'death' experiences in trances, where they entered the spirit world, etc. It was an interesting idea, but in the end I don't think there is much real evidence for it, and the most plausible explanation remains that ancient people drew the animals either as a record of their hunting victories or (more likely) in some kind of totemistic attempt to procure suffessful hunting. But everything is sheer speculation since we don't have the artists to ask. The only answer that makes any sense is "we don't know" (why they drew them).
One misconception that continues to appear, however, is that the people who drew these things were "cavemen." There is no such thing really. They did not live in the caves. It's not like Fred Flinstone. They didn't draw pretty pictures on the wall of their lounge room. The caves in which these pictures (and most others like them) occur are extremely hard places to get into. In some cases they are in the farthest possible recesses, or on high ceilings hard to reach. They were not made in everyday places for common consumption. They were special, which probably indicates a religious significance. This accords with known examples from historical times, such as the rock art of southern african tribes and Australian aboriginal peoples. The location is secret and only special members of society are allowed to view them, let alone make them.
