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A new study dates these Indonesian handprints to at least 40,000 years old.

A new study dates these Indonesian handprints to at least 40,000 years old.

Kinez Riza

Indonesian cave art may be world's oldest

The world's oldest cave art may not lie in Europe but rather halfway around the globe in Indonesia, according to a new study of the long-known art. But some archaeologists question the redating of the ancient images.

Thousands of years ago, people on the island of Sulawesi in Indonesia spray-painted stencils of their hands on the walls and roofs of caves by blowing red paint out of their mouths. They also painted strange-looking pigs in red and mulberry hues. Archaeologists assumed the paintings, discovered in the 1950s, were less than 10,000 years old. Now, a team of Australian and Indonesian researchers has found that the paintings are startlingly ancient: The hand stencils are at least 40,000 years old and the animal paintings at least 35,400 years old. That makes them about the same age or even slightly older than the famous cave art in Europe—which was until now the most ancient in the world. The discovery has important implications for how and when humans developed the ability for symbolic expression.

In Africa, where our species was born, people engraved geometric designs on chunks of hematite and ostrich eggshells as early as 78,000 years ago. But the first real sophisticated symbolic art burst on the scene about 35,000 to 40,000 years ago in Europe. At Chauvet Cave in southern France, for example, cave artists covered the walls with rhinos, horses, lions, and women with pronounced vulvas at about this time. Although some archaeologists argued that the human capacity for symbolic expression developed over time in Africa, others felt that the European creative explosion reflected a new leap in human abilities. “What was believed before our study was that Europe was the center of the earliest explosion in human creativity, especially cave art,” says geochemist and archaeologist Maxime Aubert of Griffith University, Gold Coast, in Australia, who led the new study.

Aubert’s colleague Adam Brumm, also of Griffith University, visited the Maros region of southwest Sulawesi in 2011 with Indonesian researchers and wondered if they could date the paintings. They knew that humans had been in the area at least 35,000 years ago, the age given to ocher crayons and ocher-smeared stone tools they had excavated from the Leang Burung 2 rock shelter nearby. They noticed that some of the cave art was covered with “cave popcorn,” small stalactitelike growths that formed atop the paintings when mineral-rich water trickled over the cave walls. Over the next 2 years, Aubert used a diamond saw blade to collect 19 samples of calcite popcorn from 14 paintings in seven caves within a 1-kilometer radius. He then used the concentration of naturally occurring but unstable uranium in the calcite to estimate how much time had passed since the popcorn formed, giving him a minimum age for the art. The method has been proven robust for dating corals and larger rock formations in caves and has recently been adapted to date thin deposits of carbonate on rock art.

The team was surprised to find that the oldest hand stencil dated to at least 39,900 years ago. A painting of a fruit-eating “pig-deer,” called a babirusa, on the ceiling of the same cave dated to at least 35,400 years ago, the team reports online today in Nature. (Watch a video about the research.)

The hand stencils are a bit older than the hand outlines at Chauvet, if the dates are accurate. This suggests either that humans in Europe and Indonesia each invented symbolic art at roughly the same time, or that modern humans brought their artistic capabilities with them as they spread out of Africa starting about 60,000 years ago. The authors prefer the second explanation, because it fits with archaeological evidence showing that humans were not only on Sulawesi at the time, but were also in Australia by at least 50,000 years ago. Some of the Indonesian art resembles paintings in Australia, although much of the Australian rock art is undated.

Others agree that the Indonesian paintings support the African development of symbolic behavior. “The people leaving Africa had the capacity to create images of the world around them,” says paleoanthropologist Alison Brooks of George Washington University in Washington, D.C., who has long held that view.

But everything depends on whether the new dates hold up. “I have a big question mark about the dates,” says paleoanthropologist Randall White of New York University, co-author of a paper published earlier this year in the Bulletin de la Société préhistorique française that challenged the reliability of this dating method. The thin calcite deposits on cave art can be contaminated by new flows of uranium-containing water, dust, or other detritus, making the art seem older than it is, he and his colleagues argued. He thinks the dates need to be verified with a second dating method.

Others, however, say they are satisfied that the team took special measures to date the site. For example, Aubert and his team took 55 samples of the layers of the calcite popcorn, showing that they formed a sort of ministratigraphic sequence in which the layers closest to the art were oldest and the top layers were the youngest. They also tested uranium and thorium contamination at multiple sites. “The work stands as an excellent example of how rigorous choice of samples and rigorous analysis makes the technique sound,” says archaeologist Paul Pettitt of Durham University in the United Kingdom, who was co-author of a paper applying the same method to cave art in Spain.

The team includes Thomas Sutikna of the National Centre for Archaeology in Jakarta and the University of Wollongong in Australia, who helped discover the “hobbit,” a small-statured human species from another Indonesian island, and he and Brumm are already excavating the caves near the newly dated art to search for ocher pieces, stone tools, and bones. Meanwhile, Aubert is optimistic that researchers will find more ancient art. “The discovery must surely be the tip of the iceberg,” Pettitt agrees. “So relatively little fieldwork has been undertaken on sites of this antiquity in the vastness of East Asia that it would be surprising if this were it.”