Kangaroo painted over 17,000 years ago is Australia's oldest known rock art, scientists say - CNN

So instead, the Australian team used wasp nests.

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.

There were frequent bushfires in the region that burned short-lived vegetation like grass, so most nests contained relatively recent charcoal when they were constructed.

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.