Craig Foster

These red crayon markings may be the first known human drawing

Some 73,000 years ago, a prehistoric Picasso crayoned a red hashtag design on a palm-size flake of rock in a South African cave. The artwork isn’t much to look at by modern standards, but it’s the world’s earliest known example of drawing on a surface, a new study concludes.

Researchers excavated the jagged flake in 2011 inside the oceanfront Blombos Cave. Once they had rinsed it off, they noticed nine faint red lines crisscrossing one of its surfaces. A chemical analysis revealed the lines were made of ochre, a reddish brown clay powder that can be molded into chunks. In a series of experiments, the researchers tried to reproduce the marks by either ochre paint or ochre crayon—only the crayon matched the lines’ fuzzy edges and striations. The carefully hashed lines, including one that was probably traced over back and forth, suggests it was an intentional design, the researchers report today in Nature.

Grains of sand from the same archaeological layer as the rock flake have been dated to the Middle Stone Age, between 79,000 and 75,000 B.C.E. There are earlier examples of human artistry—a similar cross-hatch pattern etched into a piece of ochre in the same cave dates to about 100,000 B.C.E—but this is the first known example of humans drawing on a surface, the authors say. (It’s unclear what the symbol meant.) The find further cements these Stone Age humans as culturally modern and behaviorally sophisticated people, the authors note.