WASHINGTON • The world's oldest known cave painting - a life-size picture of a wild pig made at least 45,500 years ago in Indonesia - has been discovered by archaeologists.

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 Agence France-Presse the painting was found on the island of Sulawesi in 2017 by doctoral student Basran Burhan, as part of surveys the archaeological team was carrying out with the Indonesian authorities.

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

It is accessible only 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 136cm by 54cm, the Sulawesi warty pig was painted using dark red ochre pigment and has a short crest of upright hair as well as horn-like facial warts characteristic of adult males of the species.

There are two handprints above the hindquarters of the pig, which 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.

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.

AGENCE FRANCE-PRESSE