Ancient Australians used boomerangs to sharpen stone tools

There’s something almost magical about the way boomerangs arc through the air and return to the hand of the thrower. Watching them cut through the sky on their wide trajectories can provide endless fascination for anyone willing to put in the time to learn to throw them correctly. Of course, if you happen to be an overactive squirrel with mischievous friends like in Hammy’s Boomerang Adventure (now streaming on Peacock!), you might have a different experience entirely.

We have known for some time that boomerangs are fun to use, and that they served an important function in Australia’s Indigenous cultures as a hunting tool. Now, new research confirms what traditional Aboriginal knowledge has long told us, that boomerangs were also used as a knapping tool for retouching lithic stone tools. Eva Francesca Martellotta from the Australian Research Centre for Human Evolution at Griffith University, in partnership with colleagues, experimentally replicated the process of retouching stone tools using boomerangs. Their results were published in the journal PLOS ONE.

As previously mentioned, there was traditional knowledge that boomerangs had been used in this way, but it had never been experimentally confirmed. Martellotta met Paul Craft, co-author on the paper, who provided invaluable insight into the traditional manufacture and use of boomerangs.

“I published another paper about boomerangs in the Sydney Museum and was doing an interview. They also interviewed Paul because he was the world champion of boomerang throwing. He’s also an Aboriginal man so he has all this knowledge about the manufacturing and use of boomerangs. He gave me huge knowledge about boomerangs and actually manufactured two of the four boomerangs we used for this study,” Martellotta told SYFY WIRE.

We know from other parts of the world that humans used bone tools to retouch their stone tools through knapping. It’s a percussive motion which breaks off flakes of stone to give a tool a new edge. When bone is used in this way, it leaves telltale markings on the bone. If wooden tools like boomerangs were used in the same way, researchers expected they might find the same sorts of use marks on their exteriors.

“When you retouch a stone tool, you create these very peculiar microscopic use marks which are very diagnostic, very easy to recognize,” Martellotta said.

During those museum searches, researchers have confirmed the existence of use marks which look strikingly like those found on bone tools in other parts of the world. This new study took the hypothesis a step further by replicating the process in the field to confirm the marks could have come from stone knapping.

“In paleolithic Europe, we have a lot of records about bone tools used to retouch stone tools. Based on the fact that bone and wood have similar properties and they’re both organic tools — elasticity and resistance is quite similar — the hypothesis was that the use marks produced during retouching would be similar to the once produced by bone,” Martellotta said.

They found that using boomerangs in this way did, in fact, created use marks similar to those found on bone tools and found in boomerang fragments housed in museums. This goes some of the way toward answering a lingering question in archaeology, whether or not wooden tools were used for various functions and to what degree.

“It’s a big unanswered question how much wooden tools were important, that’s because we don’t have a lot of preservation of wooden tools… the weather in Australia is very aggressive which makes the preservation of organic material like wood very unlikely,” Martellotta said.

Moreover, the evidence of retouching use marks on preserved boomerangs is sporadic. Many of the preserved boomerangs are relatively young, having been produced and collected around the time that Europeans arrived on the continent. A significant portion of those were produced not for hunting or knapping but to sell or exchange.

“Boomerangs were exotic tools and Europeans were very interested in having them. Most of them, especially after the first contact with Europeans, there was a tendency for Aboriginal people to make boomerangs meant to be offered to other people and never meant to be used,” Martellotta said.

This work helps to illuminate a part of human history which has been hidden through a combination of the properties of the material, the local climate, and the effects of colonization. It highlights the importance and utility of traditional knowledge and working in partnership with Indigenous peoples when studying their history. We’re able to paint a richer picture of the human story when we peer into the past together. Like a boomerang thrown into the night, we can recapture pieces of our collective heritage if we aim correctly and know where to place our hands.