A painting of a kangaroo in Western Australia is the oldest known rock art in the country, according to scientists, who say radiocarbon-dating analysis shows it was created more than 17,000 years ago.
The kangaroo depiction was among a number of rock paintings first recorded by researchers in the 1990s in the Kimberley region, which holds one of the world's largest collections of indigenous rock art. Scientists at several universities and research agencies worked with local indigenous leaders to analyze the paintings, with their findings published Monday in the journal Nature Human Behaviour.
They found the remains of 27 ancient mud wasp nests -- which can be radiocarbon dated -- above and below 16 different rock paintings, according to the paper.
The strategy is simple: if the nests are built on top of the rock art, the art must be older. If the art is built on top of nests, the nests must be older. Dating these nests thus give scientists a minimum and maximum age for the rock paintings.
The ancient nests also often contain plant material or fragments of insects that parent wasps collected for larvae to feed on, which all contain carbon.
By dating the wasp nests, the authors of this study established that the majority of paintings were produced between 17,000 and 13,000 years ago. Some of the oldest paintings include a picture of a boomerang and a rare depiction of a human figure reclining on their back. Others depicted animals including a snake, a lizard-like figure, and three macropods -- the family of marsupials that includes kangaroos, wallabies and quokkas.
The kangaroo painting was dated to between 17,100 and 17,500 years ago. It was painted on the sloping ceiling of a rock shelter, home to thousands of fossilized mud wasp nests.
"Many more dates from this period are required before the full chronological extent of the paintings still visible today can be determined," the researchers wrote.