Hand outlines painted onto the walls of Indonesian caves tell an old story. A Stone Age tale. These stencils are leading researchers to rethink who made the oldest art in the world. The Indonesian paintings are about 40,000 years old. That is roughly the same age as the oldest cave art in Europe. Two animal drawings accompany those stencils in the Indonesian caves. They, too, date to the Stone Age, new analyses find.
Scientists had long believed that people first began decorating cave walls in France and Spain. Only later, they thought, did this art spread to other parts of the world. Yet, on the Indonesian island of Sulawesi, on the other side of the planet, humans were creating art similar to what has turned up in European caves, say Maxime Aubert and Adam Brumm. These archaeologists at Griffith University in Southport, Australia, led the new study.
To create one of the stenciled hands, a person had to blow, spray or spit a liquid pigment around a hand held against the cave wall. (Pigment is a paint or dye made from natural materials.) The Sulawesi images were found decades ago. Back then, no one knew how old they were. New analyses show, though, that one of the stenciled hands is at least 39,900 years old. Nearby drawings of animals are nearly as old. Other hand stencils range from 35,000 to 17,000 years old, the scientists reported Oct. 9 in Nature.
“Our findings show that cave art was made at opposite ends of the [Stone Age] world at about the same time,” Aubert says. The finding, he says, suggests “these practices have deeper origins, perhaps in Africa before our species spread across the globe.”
Dating the art
To date the age of the stenciled hands, Aubert and Brumm’s team studied calcium-based deposits that had formed over the art. Those minerals contained a radioactive form — or isotope — of uranium. Over time, this isotope decays — giving off energy and subatomic particles. The rate at which it decays is constant and well known. By studying how much decay had occurred in the mineral deposits, the researchers could date these minerals. That provided what must be the minimum age for the art beneath the calcium deposits.
Other researchers used the same technique to date a painting in a Spanish cave. In 2012, that art was calculated to be 40,800 years old. It is the oldest known cave art. The Sulawesi hands may be as old. Dating techniques are not accurate enough to know precisely how old they might be.
Robert Bednarik agrees. He’s a self-taught authority on rock art in Australia, and did not work on the study. No method of dating a Stone Age painting is precise, he explains. In order to be confident of a painting’s age, he says other scientists must check or repeat the calculations.
Paul Pettitt, an archaeologist at Durham University in England, also did not work on the new study. Hands were particularly important tools for ancient cultures, he told Science News. That may be why people wanted to use them as stencils. The stencils may have inspired the expansion of art to other subjects, he said.
“It wouldn’t take much to observe that if the hand could be depicted in outline, so could other things, like animals,” he told Science News.
archaeology The study of human history and prehistory through the excavation of sites and the analysis of artifacts and other physical remains.
decay (for radioactive materials) The process whereby a radioactive isotope — which means a physically unstable form of some element — sheds energy and particles. In time, this shedding will transform the unstable element into a slightly different but stable element. For instance, uranium-238 (which is a radioactive, or unstable, isotope) decays to radium-222 (also a radioactive isotope), which decays to radon-222 (also radioactive), which decays to polonium-210 (also radioactive), which decays to lead-206 — which is stable. No further decay occurs. The rates of decay from one isotope to another can range from timeframes of less than a second to billions of years.
isotopes Different forms of an element that vary somewhat in weight (and potentially in lifetime). All have the same number of protons but different numbers neutrons in their nucleus. As a result, they also differ in mass.
mineral The crystal-forming substances, such as quartz, apatite, or various carbonates, that make up rock. Most rocks contain several different minerals mish-mashed together. A mineral usually is solid and stable at room temperatures and has a specific formula, or recipe (with atoms occurring in certain proportions) and a specific crystalline structure (meaning that its atoms are organized in certain regular three-dimensional patterns).
pigment A material, like the natural colorings in skin, that alter the light reflected off of an object or transmitted through it. The overall color of a pigment typically depends on which wavelengths of visible light it absorbs and which ones it reflects. For example, a red pigment tends to reflect red wavelengths of light very well and typically absorbs other colors. Pigment also is the term for chemicals that manufacturers use to tint paint.
radioactive An adjective that describes unstable elements, such as certain forms (isotopes) of uranium and plutonium. Such elements are said to be unstable because their nucleus sheds energy that is carried away by photons and/or and often one or more subatomic particles. This emission of energy is by a process known as radioactive decay.
stencil A picture or pattern that is created by temporarily holding a shape or cutout against a surface and then applying some paint or pigment along the internal or external edges of that shape or cutout. If paint is applied along the outside edges, the surface will depict the unpainted shape of the object, with sharply defined, clean internal edges. If a cutout is used, the painted shape will depict the pattern of the cutout, with sharply defined, clean external edges.
Stone Age A prehistoric period, lasting millions of years and ending tens of thousands of years ago, when weapons and tools were made of stone or of materials such as bone, wood, or horn.
subatomic Anything smaller than an atom, which is the smallest bit of matter that has all the properties of whatever chemical element it is (like hydrogen, iron or calcium).
uranium The largest naturally occurring element known. It’s called element 92, which refers to the number of protons in its nucleus. One form (isotope) is radioactive, which means it decays into smaller particles. The other form is stable.