Ancient cave paintings that look like hashtags suggest Neanderthals were not as brutish as we once thought and were even capable of symbolic thinking.
The strange etching was discovered carved into 39,000-year-old dolomite stone in a seaside Gibraltar cave, National Geographic reported.
"Originally, we could not quite believe what we had found and had to convince ourselves it was real," Gibraltar Museum director Clive Finlayson, who headed the study team told National Geographic. "Is it art? Is it a doodle? I don't know, but it is clearly an abstract design."
There has been substantial evidence that Neanderthal intelligence has been underestimated in the past. Recent studies have found the ancient humanoids buried their dead, decorated themselves with feathers, used body paint, and had a more varied diet than had been previously suspected, the BBC reported.
The symbol is believed to have been carved by a pointed tool that was repetitively run through the same groove, ruling out accidental sources for the pattern such as cutting meat.
The symbol was found in sediment underneath a layer of Neanderthal tools. It is a cross-hatched design that is about six inches across, National Geographic reported.
"The markings are significant if made by Neanderthals and would add to the increasing amount of information implying that they were capable of thinking in more or less abstract ways," Tom Higham of the University of Oxford in the United Kingdom told National Geographic.
The ledge at the back of the cave where the symbol was found is believed to be where the Neanderthals rested behind the protection of blazing campfires.
"It was a perfect place to rest and carve something," Finlayson said.
There is no evidence of early humans in this area over 39,000 years ago, which further backs up the idea that the marking was made by Neanderthals; this is the first cave carving discovered that could not have been made by modern humans.
"It follows that the ability for abstract thought was not exclusive," Finlayson told National Geographic.
