Rock art is notoriously tricky to date because it is not immediately linked to human or animal bones that can be carbon-dated. Finlayson, however, is confident that the etching was made by Neanderthals more than 39,000 years ago. A layer of sediment that once covered the engraving contained stone tools typical of those made by Neanderthals dating to between 30,000 and 39,000 years ago. This means that the engraving must be even older, Finlayson says, perhaps 40,000 to 45,000 years old. Humans did not arrive at Gorham’s Cave until more than 10,000 years later, and long after Neanderthals were gone.

The team’s dating of the Gorham etching makes it one of the oldest examples of cave art in Europe. A smudge of pigment in the Cave of El Castillo in northern Spain dates to more than 40,000 years ago, but it is not clear whether Homo sapiens or Neanderthals created it.

To better understand the engraving, Finlayson’s team tried replicating them using original Neanderthal stone tools. They found that only dozens of purposeful, repeated motions could create similar etchings. “We wanted to show that this was not a doodle, a casual thing,” he says, unlike the helter-skelter scratchings that the authors left when they sliced fresh pork skin on rock, for instance. The team’s results appear in this week’s Proceedings of the National Academy of Sciences.

Neanderthals made some of Europe’s oldest art