Researchers working in Indonesia have discovered what may be the oldest known cave paintings on Sulawesi, one of the country’s islands. It is thought that the painting is at least 45,000 years old and its age even calls into question if the makers of the painting were Homo sapiens, or perhaps a now extinct human species.

Discovered in 2017 deep in the Sulawesi cave known as Leang Tedongnge, researchers published their findings this week in Science Advances. Despite only being around 40 miles from the city of Makassar, the caves have remained largely untouched and unexplored.

The painting is a depiction of at least three small, short-legged pigs – known as a warty pig – still found on the island today. A fourth animal figure was present, but due to deterioration, its species could not be confirmed although researchers believe it was another warty pig. Due to the composition of the painting, it is thought that the animals were positioned to create a narrative scene. Above the hindquarter of the most in-tact drawing (referred to as “pig 1”), there are also two hand stencils, much like those found at Lascaux and various other locations, made with similar red and purple hues used in in the animal figures.

To date the images, small samples of the pigment used to portray the animals were removed from the cave wall. Then, using uranium-series dating, researchers were able to determine that pig 1 was at least 45,500 years old. It is possible, however, that the painting could be hundreds or even thousands of years older than presently thought because the testing only assessed the age of speleothem, one mineral found on the cave walls.

The painting is not a unique phenomenon on the island, either. In fact, in addition to other paintings discussed in the report, researchers published a paper in 2019 on another series of cave paintings on Sulawesi that were found to be 43,900 years old. At the time, the figural drawings held the top spot for the oldest known cave paintings and were touted as the “earliest hunting scene in prehistoric art.” Many of the researchers involved in the discovery of the warty pig drawings also worked on the 2019 report as well.

Another intriguing matter in the discovery is that to date, no human skeletal remains have been found on the island that are as old as the drawings. What this could mean is that the paintings were not made by “anatomically modern humans” but by another hominin. Dr Adam Brumm, one of the researchers behind the recent report, told The New York Times that he anticipates the discovery of modern human remains in the near future, which could account for the paintings.

However, archaeologist João Zilhão, who was not a part of these studies, disagrees. According to Dr Zilhão, the paintings could have been created by other hominins. “An anatomically modern human is an anatomical definition,” Zilhão said in a statement. “It has nothing to do with cognition, intelligence or behavior.”

While the painting’s creator(s) are still a mystery, what is known is that the paintings are an incredible discovery that sheds light on prehistoric peoples. The discovery also highlights the fragility of these types of paintings that are vulnerable to the elements, and as shown by portions of the Leang Tedongnge paintings, are at risk of disappearing before being rediscovered.