A Sulawesi warty pig painted in red ochre on an Indonesian cave wall may be the world’s oldest known representational image of an animal, dating back at least 45,500 years, according to a study recently published in Science Advances.

Archaeologists from Griffith University and Pusat Penelitian Arkeologi Nasional (ARKENAS) found the painting in the limestone cave of Leang Tedongne in southern Sulawesi. The painted warty pig was sampled for uranium-series dating, which was then carried out at the University of Queensland Radiogenic Isotope Facility. The results indicate that the painting was created a minimum of 45,500 years ago.
Maxime Aubert, co-leader of the team, said, ‘Rock art is very challenging to date. However, rock art produced in limestone caves can sometimes be dated using uranium-series analysis of calcium carbonate deposits (“cave popcorn”) that form naturally on the cave-wall surface used as a “canvas” for the art.’
‘At Leang Tedongne, a small cave popcorn had formed on the rear foot of one of the pig figures after it had been painted, so when dated, it provided us with a minimum age for the painting.’
The Sulaewesi warty pig is a wild boar endemic to the island, identifiable by the characteristic pair of horn-like warts near the eyes that males have, as seen in the painting.
Basran Burhan, an archaeologist from southern Sulawesi and a PhD student at Griffith, led the survey that found the cave painting. He said, ‘These pigs were the most commonly portrayed animal in the Ice Age rock art of the island, suggesting they have long been valued both as food and as a focus of creative thinking and artistic expression.’
More cave art has been recorded in Sulawesi, but it is yet to be scientifically dated. The island is part of Wallacea, a vast zone of oceanic islands between continental Asia and Australia. Humans crossed Wallacea to reach Australia by around 65,000 years ago, so even older discoveries are expected in these as-yet little explored islands.