A hand stencil in El Castillo cave, Spain, has been dated to earlier than 37,300 years ago and a red dot to earlier than 40,600 years ago, making them the oldest cave paintings in Europe (Image: Pedro Saura) Zoomed-out view of the cave art in El Castillo cave, Spain (Image: Pedro Saura)

Editorial: “Cave art appreciation opens ancient human minds to us“


As cave art goes, it doesn’t look like much: a single red dot, hidden among a scatter of handprints and drawings of animals on the wall of El Castillo cave in northern Spain.

But this red dot is at least 40,800 years old, making it the oldest known piece of cave art in Europe. At that time modern humans had only just migrated out of Africa, raising a tantalising possibility: that the dot was drawn by a Neanderthal. If that’s the case, our extinct cousins may have had the rudiments of written language.

While cave art is common throughout western Europe, the oldest dated examples are those in Chauvet cave in France, which have controversially been dated to between 35,000 and 30,000 years ago.

But many other pieces of cave art have never been dated. Standard radiocarbon dating only works when paintings were made using organic material like charcoal. Anything drawn with minerals like ochre, or just carved into the wall, can not be carbon dated.

Uranium age trick

Now, Alistair Pike of the University of Bristol, UK, and colleagues have come up with a partial solution that will put a minimum age on some previously un-datable paintings.

As water seeps through rock and dribbles over the cave surface, it leaves behind a thin layer of calcite. This contains radioactive uranium, which slowly decays into thorium at a known rate.

So, by measuring how much uranium has decayed into thorium, Pike figured he could determine the age of the calcite layer.

If the calcite overlays a painting, it will provide a minimum age for that art.

In El Castillo, the red dot lay beneath the oldest dated calcite layer. Others came close: a red hand shape on the same wall was at least 37,300 years old and a symbol that looks like the number “1” in the nearby Altamira cave was at least 35,600 years old.

The result makes these drawings the oldest known pieces of cave art in the world – so far. Pike is already examining art in other European caves to see if he can top his latest find.

Some Australian rock art apparently depicts birds that have been extinct for 40,000 years, but most of it has not been chemically dated.

Neanderthal artist?

The Spanish cave art is so old that it may not have been painted by modern humans. Homo sapiens arrived in Europe sometime between 42,000 and 40,000 years ago – right around the minimum age of the art. Yet Neanderthals had already been on the continent for tens of thousands of years. So who did the painting?

The fact is we don’t know. If modern humans were the artists, they either brought the practice with them from Africa – but left little trace of it there – or developed it incredibly quickly once they reached Europe. Pike suggests that humans changed their culture rapidly when they started competing with the Neanderthals. Cave art, he says, was a by-product of these changes. “That would explain why it happened so quickly,” he says.

The other possibility is that the paintings were done by the Neanderthals. The paintings could have been made thousands of years before they were covered in calcite. If so, Neanderthals are the only plausible candidates.

That might not be such a stretch: Neanderthals used crayon-like pigments to draw on themselves and even made simple jewellery. And there is other, indirect evidence that European caves were adorned around the time modern humans got there. Earlier this year, a team led by José Luis Sanchidrián Torti of the University of Córdoba, Spain, claimed that cave paintings found in the south of the country, near Malaga, were over 42,000 years old and therefore drawn by Neanderthals. The team dated nearby charcoal pigments, not the paintings themselves, and have not published their data.

What does it mean?

Although dramatic drawings of large animals tend to be the focus of attention, most cave art consists of simple symbols like the ones Pike studied. April Nowell of the University of Victoria in British Columbia, Canada, and her colleague Genevieve von Petzinger have found the same symbols drawn all over the world, so they may represent an early form of graphic communication. Could this mean Neanderthals were able to write? Only the discovery of similar, but older symbols will say for sure.

If you find Neanderthals writing hard to believe, get this: an alternative interpretation of the hand stencils suggests they are the leftovers of early religion.

Paul Pettitt of the University of Sheffield, UK – one of Pike’s collaborators – has just completed an extensive study of the hand stencils, which are found in El Castillo and elsewhere.

His as-yet-unpublished data shows the symbols tend to be placed in places that are difficult to reach. “One involves a climb up a slippery stalactite,” he says. Others are found up chimneys. “They seem to be marking passages off the main areas,” Pettitt says. One interpretation is that they are signposts, perhaps saying “do not go this way”.

They may have a more profound meaning. Pettitt found that they were often placed over cracks in cave walls, or right next to them. Such cracks, he says, may have been seen as gateways to a supernatural world. He points out that caves are often associated with the supernatural, in part because they are dark and quiet, and people’s sense of time is altered if they spend time in them.

Similar ideas have been put forward by Jean Clottes, who excavated Chauvet, and David Lewis-Williams of the University of Witwatersrand in South Africa. They have linked cave art with shamanism, and suggest that early humans saw the cave wall as a veil between this world and the next.

“I would have to see Pettitt’s study and see what the stats are like,” Nowell says. “I can think of many examples of hands not near cracks,” she adds, and it is also impossible to determine the symbols’ meaning. “But these are things that have been said in one form or another before and no one has been able to test for meaning scientifically.”

Whether or not the use of caves as religious sites goes right back to the arrival of humans in Europe, for now, remains shrouded in history.

Journal reference: Science, DOI: 10.1126/science.1219957

This article has been edited since it was first posted