A warty pig painted on a cave wall 45,500 years ago is the world's oldest depiction of an animal

The world's oldest known figurative artwork has been discovered in a cave in Indonesia -- an endearing image of a warty pig.

Archeologists working on the site on the island of Sulawesi said the cave art was at least 45,500 years old. It is also thought to be the oldest surviving image of an animal. Painted using red ocher pigment, the animal appears to be observing a fight or social interaction between two other warty pigs.

This region is home to many intriguing limestone caves where other discoveries have been made. Cave art depicting a hunting scene dating to 43,900 years ago was also found in Sulawesi in late 2019. The same team of archeologists in 2014 found human hand stencils, which were dated to 40,000 years ago.

Previously, the oldest known cave art was thought to have first appeared in Europe 40,000 years ago, showcasing abstract symbols. By 35,000 years ago, the art became more sophisticated, showing horses and other animals.

These latest finds in Indonesia have challenged a long-standing belief that artistic expression -- and the cognitive leap that may have accompanied it -- began in Europe. The cave paintings in Indonesia are shedding new light on the early story of humanity.

Study coauthor Maxime Aubert, an archeologist and associate professor at Griffith University in Australia who specializes in the dating of rock art, said that view was "Eurocentric."

It's now thought that the capability to create figurative art -- that references the real world -- either emerged before Homo sapiens migrated out of Africa and headed for Europe and Asia more than 60,000 years ago or that it emerged more than once as humans spread around the globe.

DATING CAVE ART

While abstract art has been found in Africa dating back to 77,000 years ago, no figurative art older than those found on sites in Europe and Indonesia has been discovered on the African continent, Aubert said.

One reason for that could be because it's particularly difficult to date cave art, Aubert explained. However, rock art made in limestone caves can sometimes be dated by measuring the radioactive decay of elements like uranium within the calcium carbonate deposits -- sometime called cave popcorn -- that form naturally on the cave surface.

This was the case at the Leang Tedongnge site in southern Sulawesi, where a small cave popcorn had formed on the rear foot of the pig figure after it had been painted. The date indicates the scene had been painted prior to 45,500 years ago, Aubert said, and the cave art could be much older.

A second Sulawesi warty pig image, from another cave in the region, was dated to at least 32,000 years ago using the same method in the study that published in the journal Science Advances on Wednesday.

The team expects future research in eastern Indonesia will lead to the discovery of much older rock art and other archaeological evidence, dating back at least 65,000 years.

"We have found and documented many rock art images in Sulawesi that still await scientific dating. We expect the early rock art of this island to yield even more significant discoveries," said study coauthor and Indonesian rock art expert Adhi Agus Oktaviana, a doctoral student at Griffith University. 

PREHISTORIC PICASSOS

The researchers were confident the image was of a warty pig, which is shown in profile and filled in with irregular patterns of painted lines and dashes, because of the presence of spiky head crests and facial warts -- the two conspicuous, hornlike protusions in the upper snout area.

The pig painted on the ceiling of the cave measures 187 centimeters (6 feet) in length and 110 centimeters (3.6 feet) in height and is a red or mulberry colour -- the prehistoric artists used iron-rich rock as a pigment and could have used two colours. The researchers said there are three other pigs in the scene.

Warty pigs are still common in Indonesia and have since been domesticated.

Not much is known about the people who made the art, Aubert said.

Research has indicated that Homo sapiens arrived in Southeast Asia between 60,000 and 70,000 years ago. While the researchers said they are unable to definitively conclude that the artwork is the handiwork of cognitively modern humans, that was the most likely explanation.

"Our species must have crossed through Wallacea by watercraft in order to reach Australia by at least 65,000 years ago," said Aubert, referring to the region between continental Asia and Australia.

"However, the Wallacean islands are poorly explored, and presently the earliest excavated archaeological evidence from this region is much younger in age."

Nonfigurative artwork has been attributed to other early humans, with rock art found in Spain believed to be the handiwork of Neanderthals -- who overlapped with Homo sapiens for about 30,000 years before disappearing 40,000 years ago. However, this finding has been contested.

The depiction of the warty pig is also older than other types of prehistoric artwork found in Europe such as the "Lion-man," a figurine of a lion-headed human, and a "Venus figurine" carved from mammoth ivory, both found in Germany and thought to be around 40,000 years old.

It's also more ancient than a recent find on another Indonesian island -- an image of cattle that was found in a cave in Borneo.

"This discovery underlines the remarkable antiquity of Indonesia's rock art and its great significance for understanding the deep-time history of art and its role in humanity's early story," said study coauthor Adam Brumm, a professor at Griffith's Australian Research Centre for Human Evolution.