Where does art come from? Indonesian cave paintings deepen mystery.

Paintings of miniature buffalos, warty pigs and human hands covering the walls and ceilings of caves in Indonesia could be among the oldest examples of cave art in the world, a new study finds.

The paintings — some of which might be more than 40,000 years old — challenge Europe's standing as the birthplace of prehistoric art.

"It was previously thought that Western Europe was the centerpiece of a 'symbolic explosion' in early human artistic activity, such as cave painting and other forms of image making, including figurative art, around 40,000 years ago," said study leader Maxime Aubert, an archaeologist and geochemist at Australia's Griffith University. "However, our findings show that cave art was made at opposite ends of the Pleistocene Eurasian world at about the same time, suggesting these practices have deeper origins — perhaps in Africa before our species left this continent and spread across the globe." [See Photos of the Stunning Cave Art from Indonesia]

Sulawesi caves

The paintings were found in the karst caves of Sulawesi, an island just east of Borneo with four long peninsulas that radiate like flower petals. Archaeologists have known about the cave art for decades. They've also found shellfish, animal bones, pigment-stained stone tools and even ochre "crayons" inside these caverns.

The cave paintings were assumed to be prehistoric, but relatively "young," perhaps created by the region's first farmers a few thousand years ago or hunter-gatherers around 8,000 years ago at the earliest, Aubert told Live Science in an email. But scientists had never tried to date the artworks before.

Stylistically, some of the paintings resemble those found in Europe. There are hand stencils that would have been created as a person spit or sprayed red pigment over his or her hand to leave the outline of a handprint. These look quite similar to the hand stencils found in the El Castillo cave in Spain, estimated to be 37,300 years old. (At 40,800 years old, a red disk on the wall of El Castillo cave was proclaimed to be the oldest reliably dated wall painting ever in a 2012 study in the journal Science.)

As for the figurative paintings, artists in Europe and Southeast Asia apparently shared a favorite subject: wild animals. But while prehistoric paintings in places such as Chauvet Cave in France depict cave lions, horses and hyenas, the animals represented in Sulawesi include fruit-eating pig-deer called babirusas, Celebes warty pigs and midget buffalos also known as anoas.

Prehistoric 'popcorn'

Adam Brumm, an archaeologist at Australia's University of Wollongong, first noticed small cauliflowerlike knobs on some of the hand stencils while doing research in Sulawesi in 2011. These crusty bumps were actually calcite deposits known as coralloid speleothems or, more informally, "cave popcorn." The deposits contain tiny amounts of radioactive uranium, which decays to thorium over time. By measuring the ratio of uranium to thorium in the layers of cave popcorn, scientists can determine the minimum age of underlying artwork.

Aubert and his colleagues determined the age of 14 paintings inside seven caves. The artworks range in age from 17,400 years old to 39,900 years old, the study found. But since uranium dating of the cave popcorn layer that grew on top of the art only provides a minimum age, these paintings could be much older, the researchers said. The findings were published today (Oct. 8) in the journal Nature. [The Top 10 Mysteries of the First Humans]

The oldest painting — a hand stencil — was discovered on a 13-foot-high (4 meters) ceiling in a cave known as Leang Timpuseng in Sulawesi's southwestern peninsula. The researchers say this is now the earliest known example of a hand stencil, and it also represents the earliest evidence for a human presence on Sulawesi.

In the same cave, a painting of a babirusa was found to be at least 35,400 years old. That means this pig-deer could be the oldest known figurative work of art in the world — older than the beasts that line the walls of Chauvet Cave.

Origins of art

The revelation that art was being made on opposite sides of the world during the Ice Age suggests that symbolic painting could have originated independently — or perhaps art-making originated much earlier, in Africa, where humans evolved before marching out to other continents about 100,000 years ago.

Benjamin Smith, a rock-art expert and a professor at the University of Western Australia who was not involved in the study, said it is "highly important, but not surprising, that we have finally found evidence that settlers in Southeast Asia had rock art as part of their cultural package some 40,000 years ago."

Archaeologists already had some clues that this "cultural package" predated the cathedrals of cave art in Europe. Ochre, a reddish natural pigment, has been found on human remains in burials in Israel dating back to 100,000 years ago, Smith said, and humans left decorated pieces of ochre and ostrich eggshell in caves in South Africa as early as 100,000 years ago.

But whether figurative art developed before the exodus from Africa or soon thereafter remains to be seen, Smith told Live Science.

"But what is clear is that those who continue to try to place Europe at the center of the human story hold an untenable position," Smith wrote in an email. He thinks scientists studying the origins of art and symbolic thought should instead shift their attention to Africa, Asia and Oceania.

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