No one who has stood in that passage since the man died — not the 1988 cavers, not the researchers who followed, not anyone in the thousands of years between — has made those specific marks.

They are his marks, or the marks of others who entered the cave in the ancient period, but in either case they are marks that predate modern caving and modern Colorado by thousands of years.

The marks are evidence of a human presence that otherwise left almost nothing.

No tools were found with the bones.

No food remains.

No artifacts that would place the man in a cultural tradition or help identify his community.

Just the bones, the radiocarbon dates, the mitochondrial DNA — and the torch marks on the cave walls.