There's a little heat crack over one of the "spray" lines, so they think they can date it. There were volcanoes roughly around that period. But...
I'd expect the spray to be more uniformly spread around. Unless it came out of two opposite cracks in the volcano? Lots of lines went into each of the sprays, so the artist (if so) could have spread them around without much more effort. (I'm assuming that the lines originated near the animal head instead of farther out--easier to start more or less uniform than end up that way. They could look at the grooves and be sure.)
But just to be cantankerous, what else could the spray lines have been?
- Erasure. Somebody didn't like what was put there before, and scratched it out violently. &$#! graffiti kids
- Illustrating which ways this kind of critter tends to use in escaping, to class after class of newbie hunters
- Magical summons--follow the path to our hunters
- Somebody tried to draw geysers
The lower image is a volcano image from Turkey. The article claims this cave thing is older, which it probably is. What do you think it is?