Talk about outsider art: Researchers say they have found the first evidence of abstract art created by Neanderthals in a cave above the Mediterranean Sea.
The "art," pictured above, was found toward the back of a cave in Gibraltar at the southern tip of the Iberian Peninsula. It consists of 13 lines of various depths and widths that were deliberately carved into a natural stone platform that sits about 1 foot above the cave floor.
A paper describing the discovery was published Monday in the journal PNAS.
Radiocarbon dating suggests the engravings were made at least 39,000 years ago, when the cave was inhabited by Neanderthals who left a smattering of their tools behind, according to the paper.
The researchers do not attempt to guess what the Neanderthal artist may have been trying to say with this geometric carving, but they spent a lot of time figuring out how it was created. To try to re-create it, they used seven stone tools to carve into three weathered blocks of limestone.
To see whether the pattern was made by accident, perhaps while cutting meat, they tried slicing fresh pork skin on the limestone using period tools. However, the grooves made that way were more superficial than the lines found in the cave.
They also tried scratching back and forth on the rock, but found it was too difficult to make a straight line that way. Eventually, they determined that the deep grooves in the rock were made by at least 54 strokes in the same direction, and the shallower, more narrow lines were created by four to 30 strokes in the same direction.
In other words, these lines appear to have been deliberately drawn.
According to the researchers, it provides another layer of evidence that Neanderthals were more sophisticated than previously thought.
"We conclude that this engraving represents a deliberate design conceived to be seen by its Neanderthal maker and, considering its size and location, by others in the cave as well," they authors write in the paper. "It follows that the ability for abstract thought was not exclusive to modern humans."