Archaeologists have discovered the world’s oldest known cave painting: a life-sized picture of a wild pig that was made at least 45,500 years ago in Indonesia.

The finding described in the journal Science Advances on Wednesday provides the earliest evidence of human settlement of the region.

Co-author Maxime Aubert of Australia’s Griffith University told AFP it was found on the island of Sulawesi in 2017 by doctoral student Basran Burhan, as part of surveys the team was carrying out with Indonesian authorities.

The Leang Tedongnge cave is located in a remote valley enclosed by sheer limestone cliffs, about an hour’s walk from the nearest road.

It is only accessible during the dry season because of flooding during the wet season — and members of the isolated Bugis community told the team it had never before been seen by Westerners.

Measuring 136 by 54 centimeters (53 by 21 inches) the Sulawesi warty pig was painted using dark red ochre pigment and has a short crest of upright hair, as well as a pair of horn-like facial warts characteristic of adult males of the species.

There are two hand prints above the pig’s hindquarters, and it appears to be facing two other pigs that are only partially preserved, as part of a narrative scene.

“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.

Early human migration

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.