When ancient humans created cave art, they purposely deprived themselves of oxygen while deep inside of the caves.
Researchers from Tel Aviv University analyzed several paintings in European caves (with the majority of them being in France and Spain) that date back to between 40,000 and 14,000 years ago during the Upper Paleolithic Period. They discovered that these paintings were created in narrow passageways or halls where the artists could have only used artificial light in order to see what they were doing.
According to the study, “It appears that Upper Paleolithic people barely used the interior of deep caves for daily, domestic activities. Such activities were mostly performed at open-air sites, rock shelters, or cave entrances.” “While depictions were not created solely in the deep and dark parts of the caves, images at such locations are a very impressive aspect of cave depictions and are thus the focus of this study.”
When they created the art deep within the cave, they would have used fire as light. The problem with that form of artificial light was that the oxygen levels would have been decreased to the point where the painters would have been in a state of hypoxia which could have caused headaches, disorientation, change in behavior, reduced level of consciousness, out-of-body experiences, and hallucinations.
Hypoxia occurs when the body is subjected to conditions where the oxygen levels are below 18%. And based on the closed area where the cave paintings were created as well as the limited amount of air circulation, and the fact that fire was used to see what they were doing, the ancient humans would have been subjected to exceptionally low oxygen levels – possibly as low as 11%.
In an interview with CNN, Ran Barkai, who is a professor of prehistoric archaeology and a co-author of the study, stated that the ancient painters did this on purpose in order to better connect with the cosmos. He went on to note that the artists believed the rock they were painting somehow connected their world to the underworld as part of their beliefs.
While many experts over the years have attempted to figure out the significance of the animals depicted in so many cave paintings (such as bison, ibex, and mammoths), this new study argues a different theory, “It was not the decoration that rendered the caves significant but the opposite: The significance of the chosen caves was the reason for their decoration.”
More research needs to be conducted to better understand these ancient oxygen-depriving events, such as were they a form of initiation and why were children present in such deep locations in the caves? Another mystery was whether or not these ancient humans somehow developed a resistance to the low oxygen levels so much so that it didn’t affect them.
The study was published in Time and Mind: The Journal of Archaeology, Consciousness and Culture where it can be read in full.