Could Neanderthals speak? The answer may depend on whether they used make-up.
Francesco d'Errico, an archaeologist from the University of Bordeaux, France, has found crafted lumps of pigment – essentially crayons – left behind by Neanderthals across Europe.
He says that Neanderthals, who most likely had pale skin, used these dark pigments to mark their own as well as animal skins. And, since body art is a form of communication, this implies that the Neanderthals could speak, d'Errico says.
Working with Marie Soressi of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, d'Errico has recovered hundreds of blocks of black manganese pigment from two neighbouring sites at Pech de l'Azé in France, which were occupied by Neanderthals. These add to evidence of pigment among Neanderthal from some 39 other sites.
The pigments were not just smeared onto the body like camouflage, d'Errico says, but fashioned into drawing tools.
"The flat, elongated surfaces on the archaeological specimens are consistent, as confirmed experimentally, with producing clearly visible straight black lines, perhaps arranged to produce abstract designs," says d'Errico, who presented his work on 15 March at the Seventh Evolution of Language Conference in Barcelona, Spain.
Body painting, argues d'Errico, is a "material proxy" for symbolic communication. What's more, he says, the techniques for making the symbols, and the meaning they carry, would have to be transmitted through language.
And body painting isn't the only proxy associated with Neanderthal remains. Neanderthals adorned their bodies with ornamentation, such as necklaces made from shell beads.
The sorts of beads used by modern humans, and the ornaments they fashioned from them, vary geographically. This is often interpreted as a sign of ethnic and cultural diversity among humans, and a means of symbolically binding groups and differentiating them from others. D'Errico suggests that the same holds true for Neanderthals.
Other researchers agree, and point to a double standard of some researchers in interpreting the archaeological record, including evidence of burials, care of the infirm and social cooperation.
"Some archaeologists are happy to associate these same features with language if they occur with modern humans, but are not willing to associate them with language among the Neanderthals," says anthropologist Erik Trinkaus of Washington University in St Louis, US.
"The double standard doesn't work - if they reflect language in one, they must reflect in it both."
However, even if Neanderthals had language capabilities, that does not mean they spoke in the same way as humans.
"The archaeological record does not show that they ever attained the cultural level of the humans who could talk as we do," says Phillip Lieberman, a linguist at Brown University, Rhode Island, US.
"Neanderthals possessed language, but their linguistic and cognitive ability was inferior to the humans who replaced them," he says.