Scientists dated the painting with the help of ancient wasp nests.
Scientists can now point to a large kangaroo as Australia's oldest intact rock painting.
A team led by researchers at the University of Melbourne dated the painting in Western Australia to between 17,100 and 17,500 years old, settling on 17,300 as the likely age. To handle the tricky art of figuring out the painting's age, they got creative and turned to radiocarbon dating of mud wasp nests.
Radiocarbon dating lets scientist make age estimates for organic materials. The location of several wasp nests both under and over the pigment made it possible to dial in when it was created.
The painting was found on the ceiling of a rock shelter. The depiction of the kangaroo is part of the "Naturalistic period" of Indigenous rock art. The painting is a clear representation of a kangaroo and is also about 6.5 feet (2 meters) long, making it life-size.
Using the wasp-nest method, researchers hope to gain a better understanding of when different styles of rock art came into existence. The work could also lead to the confirmation of even older paintings than the kangaroo.
The team published its findings on Monday in the journal Nature Human Behavior. The study is part of a larger project focused on dating paintings in the Kimberly region of Australia, an area known for Aboriginal rock art. Multiple universities and organizations, including Rock Art Australia and the Balanggarra Aboriginal Corporation, are involved in the project.
"It's important that Indigenous knowledge and stories are not lost and continue to be shared for generations to come," said Cissy Gore-Birch of the Balanggarra Aboriginal Corporation. "The dating of this oldest known painting in an Australian rock shelter holds a great deal of significance for Aboriginal people and Australians and is an important part of Australia's history."