Aliens!
Come on you all, be a little rational. The obvious explanation is that if you did as much DMT and other powerful psychedelics as much as ancient people did, you would probably start hallucinating all type of shyt and start putting that in your drawings.
Google "DMT artwork" and see the results. That's what people in 2020 draw after they get high. They draw what they see. That's today as well. Ain't no ancient motherfukker painting in a cave. DMT artwork is people right now this very moment using Microsoft Paint or Photoshop or whatever to draw what they saw on their trip. And its literally the exact same shyt as this ancient artwork