Archaeologists have discovered the oldest known cave painting in the world: a life-sized picture of a wild pig produced in Indonesia at least 45,500 years ago.
The finding described on Wednesday in the journal Science Advances provides the earliest evidence of the region’s human settlement.
Co-author Maxime Aubert of Australia’s Griffith University told AFP that doctoral student Basran Burhan discovered it on the island of Sulawesi in 2017, as part of the team’s surveys with Indonesian authorities.
In a remote valley enclosed by sheer limestone cliffs, about an hour’s walk from the nearest road, the Leang Tedongnge cave is located.
Due to flooding during the wet season, it is only accessible during the dry season — and members of the isolated Bugis community told the team that Westerners had never seen it before.
The Sulawesi warty pig was painted with dark red ochre pigment measuring 136 by 54 centimeters (53 by 21 inches) and has a short crest of upright fur, as well as a pair of horn-like facial warts typical of the adult males of the genus.
Above the pig’s hindquarters there are two hand prints, and as part of a narrative scene, it appears to be facing two other pigs that are only partly preserved.
“The pig appears to be observing a fight or social interaction between two other warty pigs,” said co-author Adam Brumm.
Humans have hunted Sulawesi warty pigs for tens of thousands of years, and they are a key feature of the region’s prehistoric artwork, particularly during the Ice Age.
Aubert, a dating specialist, identified a calcite deposit that had formed on top of the painting, then used Uranium-series isotope dating to confidently say the deposit was 45,500 years old.
This makes the painting at least that age, “but it could be much older because the dating that we’re using only dates the calcite on top of it,” he explained.
“The people who made it were fully modern, they were just like us, they had all of the capacity and the tools to do any painting that they liked,” he added.
The previously oldest dated rock art painting was found by the same team in Sulawesi. It depicted a group of part-human, part-animal figures hunting mammals, and was found to be at least 43,900 years old.
Cave paintings such as these also help fill in gaps about our understanding of early human migrations.
It’s known that people reached Australia 65,000 years ago, but they would probably have had to cross the islands of Indonesia, known as “Wallacea.”
This site now represents the oldest evidence of humans in Wallacea, but it’s hoped further research will help show people were in the region much earlier, which would resolve the Australia settlement puzzle.
The team believes the artwork was made by Homo sapiens, as opposed to now extinct human species like Denisovans, but cannot say this for certain.
To make handprints, the artists would have had to place their hands on a surface then spit pigment over it, and the team are hoping to try to extract DNA samples from residual saliva.