Modern critics would probably hail the up and coming rock artists that once inhabited Indonesia. About a hundred caves outside Moras, a town in the tropical forests of Sulawesi, were once lined with hand stencils and vibrant murals of abstract pigs and dwarf buffalo. Today only fragments of the artwork remain, and the mysterious artists are long gone.

For now, all we know is when the caves were painted—or at least ballpark dates—and the finding suggests that the practice of lining cave walls with pictures of natural life was common 40,000 years ago. A study published today in Nature suggests that paintings in the Maros-Pangkep caves range from 17,400 to 39,900 years old, close to the age of similar artwork found on the walls of caves in Europe.

“It provides a new view about modern human origins, about when we became cognitively modern,” says Maxime Aubert, an archaeologist at Griffith University in Australia. “It changes the when and the where of our species becoming self-aware and starting to think abstractly, to paint and to carve figurines.”

Swiss naturalists Fritz and Paul Sarasin returned from a scientific expedition to Indonesia between 1905 to 1906 with tales of ancient rock shelters, artifacts and cave paintings, but few specifics. Dutch archaeologist H. R. van Heereken first described the cave paintings around Maros in 1950, and though Indonesian researchers have done significant work in the caves, little has been published on them since.

Work by local scientists describes more recent charcoal drawings that depict domesticated animals and geometric patterns. It also mentions patches of potentially older art in a red, berry-colored paint—probably a form of iron-rich ochre—that adorns cave chamber entrances, ceilings and deep, less accessible rooms. Previous estimates put the Maros cave art at no more than 10,000 years old. “People didn’t believe that cave paintings would last for that long in caves in a tropical environment,” says Aubert.

Dating cave paintings can prove extremely difficult. Radiocarbon dating can be destructive to the artwork and can only be used to date carbon-containing pigment—usually charcoal. This method also gives you the age of the felled tree that made the charcoal, rather than the age of the charcoal itself. Bacteria, limestone and other organic material can further skew the dating results. “We often see wildly varying radiocarbon dates from the same painting,” says Alistair Pike, an archaeologist at the University of Southampton who was not affiliated with the study.

While excavating archaeological remains in the caves, Adam Brumm, a co-author and archaeologist at the University of Wollongong in Australia, noticed “cave popcorn” on some of the artwork. This layer of bumpy calcite would eventually become stalactites and stalagmites millennia down the road, but most importantly it contains uranium—a radioactive substance that can be used to estimate a painting’s age.

Aubert and his colleagues collected 19 samples taken from the edges of 14 works of art across seven cave sites. The images ranged from simple hand stencils to more complex animal depictions. In the lab, they estimated the age of the paintings based on uranium isotopes in the samples. In some cases, calcite layers were found above or beneath the art. “If I have a sample on top, it’s a minimum age, and if it’s on the bottom of the painting, then it’s a maximum age,” explains Aubert.

Most of the artwork is around 25,000 years old, which puts it among the oldest artwork in Southeast Asia. But some turned out to be significantly older than expected. “It was a bit of a shock,” says Aubert with a chuckle. One hand stencil dates to at least 39,900 years ago, making it the oldest example of hand stenciling in the world. Some of the animal artwork sets records as well: a painting of a female babirusa, or “pig-deer”, is at least 35,400 years old.

These dates are within spitting distance of some of Europe’s oldest rock art and sculptures. Using uranium dating, Pike’s team previously put hand stencils and geometric paintings in Spain’s El Castillo cave as the oldest on record: a maximum of 40,800 years old. More complex naturalistic images of animals at the famous Lascaux caves in France are around 20,000 years old, while those in Chauvet, France, measure around 32,000 years old—though some refute that date. Animal sculptures found in caves in Germany date to a similar time period, as well.

Scientists traditionally thought that humans began creating art once they reached Europe from Africa, and that human art forms dissipated to the far reaches of the globe from there. “It’s a pretty Euro-centric view of the world,” says Aubert. “But now we can move away from that.” The study provides compelling evidence that artists in Asia were painting at the same time as their European counterparts. Not only that, they were drawing recognizable animals that they probably hunted.

“This raises several interesting possibilities,” says Pike. Rock art may have emerged separately in these disparate locales. Given that simple hand stencils show up all over the world, he points out, that wouldn’t be too surprising. Then there’s the possibility that upon leaving Africa, around 70,000 years ago, modern humans had already developed artistic know-how, which they brought with them as they settled Europe and Asia. If that is true, there’s even more ancient cave art waiting to be discovered between Europe and Indonesia. Aubert has a hunch that’s the case: “It’s just that we haven’t found them or dated them yet. I think it’s only a matter of time.”