Since their discovery in 1994, the spectacular paintings of lions, rhinos, and other animals in southern France's Chauvet Cave  have stood out as the oldest known cave art, clocking in at about 37,000 years old.* But there have been occasional sightings of other cave art that is equally ancient, although its dating has been more uncertain. Now a team working at another site in the south of France claims to have discovered what appear to be engravings of female genitalia that are as old as or older than Chauvet, possibly making them the world's most ancient cave art.
Homo sapiens first colonized Europe from Africa around 40,000 years ago. But until the early 1990s, there was little firm evidence that our species engaged in sophisticated artistic activity that early. Many archaeologists assumed that modern humans developed their artistic skills only gradually, culminating in spectacular galleries like the 15,000-year-old painted caves at Lascaux  in France and Altamira  in Spain. The discovery of Chauvet changed all that and convinced most researchers that early artists had brought their skills with them from Africa .
Yet for years Chauvet seemed to stand alone, leading some archaeologists to question whether its dating—based in large part on radiocarbon samples taken directly from its charcoal paintings—was correct. Nevertheless, evidence for other art of about the same age continued to accumulate . At Fumane Cave in Italy, for example, archaeologists found depictions of animals and what appeared to be a half-human, half-beast figure , dated to about 37,000 years ago or even older, although the error ranges for the dates were fairly wide.
Since 1994, the year of Chauvet's discovery, a team led by archaeologist Randall White of New York University in New York City has been working at the Abri Castanet, a rock shelter (a shallow cave usually at the base of a cliff) in southern France's Vezere valley. Originally excavated in the early 20th century, the Abri Castanet has long been considered one of the earliest modern human sites in Europe, with occupation layers dated back to nearly 40,000 years ago. White's excavations have uncovered considerable evidence of symbolic and artistic activity at the site, including hundreds of pierced snail shells apparently used as ornaments and three limestone blocks adorned with engravings, including one the team interprets as a vulva. But the blocks, which came from the shelter's collapsed roof, were impossible to date because they do not contain the kind of organic matter necessary for radiocarbon analysis.
In 2007, however, the team began excavating another large block that had fallen from the roof and directly onto a segment of the cave floor once occupied by prehistoric humans. As White and his colleagues broke the stone slab into sections and lifted them out, they discovered that the underside had been engraved with another vulva-like image (see photo). When they sent the bones of reindeer and other animals from the cave floor to the University of Oxford's radiocarbon dating lab for analysis, the dates clustered tightly between 36,000 and 37,000 years ago. And because there was no accumulation of sediments or other deposits between the archaeological layer and the stone slab, the team argues that the painted cave ceiling must be at least as old as the bones.
That would mean that the artworks at Abri Castanet are also at least as old as those at Chauvet , White and co-workers conclude in a paper published online today in the Proceedings of the National Academy of Sciences. Because these images of vulvas are very different from the charcoal and ochre drawings at Chauvet, the team thinks that regional differences in artistic traditions were already established in Europe by that time, even at sites like Chauvet and Abri Castanet that are only a few hundred kilometers apart.
One key difference, White says, is that whereas the paintings at Chauvet are hidden deep within that cave and away from living areas, the depictions at Abri Castanet were on the rock shelter ceiling right above the spaces where prehistoric humans slept and ate, making them a kind of everyday and public art.
Harold Dibble, an archaeologist at the University of Pennsylvania, says the team's dating of the vulva engraving appears sound because it cannot be any younger than the surface onto which it fell and might even be older. "The context of the find is quite clear," Dibble says. As for the long-standing tradition among archaeologists working in France of interpreting such images as vulvas, Dibble says, "Who the hell knows" what they really represent? Dibble adds that such interpretations could be colored by the worldview of Western archaeologists whose culture probably differs greatly from that of prehistoric peoples. "Maybe it's telling us more about the people making those interpretations" than the artists who created the images, Dibble says. On the other hand, he says, the repeated use of this image at other sites in the Vezere valley suggests that it was some sort of "shared iconography" that might identify specific groups of people. Indeed, archaeologists have also identified differences in the styles of personal ornaments and other artifacts that might also reflect different groups or tribes, much as people express their group identities by the way they dress today.
Paul Pettit, an archaeologist at the University of Sheffield in the United Kingdom, agrees that the new work "provides admirable independent verification of the age of the Castanet rock art that has been suspected for decades." What's more, argues Pettit, a leader of a small but vocal group of archaeologists who have questioned the dating of the Chauvet paintings, the discovery at Abri Castanet helps make their case that the Chauvet art is too sophisticated to be 37,000 years old. "The only other examples of convincingly dated rock art in this period are the painted block from Fumane, which in terms of technical achievement is similar to the Castanet examples," he says. The reason there are so many stylistic differences between the spectacular Chauvet paintings and the relatively simple engravings at Abri Castanet, he insists, is that the Chauvet images are much younger.
* All dates in this story are calibrated to account for differences in the amount of radiocarbon in Earth's atmosphere between prehistoric times and today
Correction, 25 May: An earlier version of this story said incorrectly that the radiocarbon calibration  curve accounts for fluctuations in the amount of carbon dioxide in the atmosphere: it actually accounts for fluctuations in the total amount of radiocarbon in the atmosphere.