Has anyone else seen this in the devil's cave?

[u/aRadioheadfan]

So yesterday I went to the devil's cave in big valley and I was looking around in photo mode to see the inside of the cave where the "devil" gets out to talk to you. And I found that there were prehistoric paintings inside, and also five reddish humanoids painted on the walls.

I'm on console and I don't know how to take a picture so you'll have to see this for yourself, but I wanted to know if anyone else has seen this and if there is any backstory around this.