By Ciarán Mather
Little did one ancient Aborigine know that his or her humble past-time of painting a kangaroo on a cave wall would become so significant to historians in the future.
A painting which was initially discovered in the 1990s in the Kimberley region of Western Australia has been confirmed to be at least 17,000 years old: making it the oldest cave painting ever found.
The team of scientists who analysed the paintings were aided by local indigenous leaders.
They also revealed that they used something rather unusual to confirm the age of the painting: wasp nests.
The team reported that they found the remains of 27 ancient mud wasp nests, which could be radiocarbon dated, above and below 16 different rock paintings.
They devised a strategy to indicate the age of the paintings: if the nests are built on top of the rock art, the art must be older.
Conversely, if the art is built on top of nests, the nests must be older.
Even with today's technology, it has proven a challenge to date paintings older than 6,000 years, since organic material in the paint pigment, which is crucial for radiocarbon dating, is often incredibly hard to find.
In the case of the kangaroo cave paintings, the main source of carbon in these nests, which are made partly from mud, is from charcoal fragments.
While hopeful of their findings, the team made sure to stress that 'many more dates from this period are required before the full chronological extent of the paintings still visible today can be determined.'
The science team's findings have since been published in the journal Nature Human Behaviour.