40,000-year-old mammoth tusk boomerang is oldest in Europe — and possibly the world

An unusual mammoth tusk boomerang discovered in a cave in Poland is 40,000 years old — making it Europe's first example of this complex tool and possibly the oldest boomerang in the world, a new study finds.

"The ivory object has all the features of boomerangs used by Aborigines in Queensland today," study co-author Paweł Valde-Nowak, an archaeologist at Jagiellonian University in Krakow, Poland, told Live Science in an email. "Its arched shape, flat-convex cross-section and dimensions match the Queensland boomerangs that do not return to the thrower," he said.

The new study, published Wednesday (June 25) in the journal PLOS One, shows that curved throwing tools were invented in Europe far earlier than expected.

The crescent-shaped artifact — which is about 28 inches (72 centimeters) long — was found in Obłazowa Cave in southern Poland 40 years ago along with human bones, pendants made from fox fangs, and stone blade tools, all covered with red ocher. Valde-Nowak and colleagues published their original findings in the journal Nature in 1987, suggesting the cave was used off and on by Neanderthals and early humans during the Middle to Upper Paleolithic periods (300,000 to 12,000 years ago).

The Upper Paleolithic (50,000 to 12,000 years ago) is a key period in human history, as humans invented new forms of tools, cave art and personal decoration. And at Obłazowa Cave, Valde-Nowak saw a clear difference between the ocher-covered finds and earlier artifacts at the same site.

"In my opinion, this is absolutely clear evidence of behaviors unknown to us, practices of early Homo sapiens, which contrast sharply with everything we found in the deeper cultural layers in Obłazowa, layers left by Neanderthals," Valde-Nowak said.

Related: This man was killed by brutal boomerang blow 800 years ago

To better understand the chronology of the Obłazowa Cave, in 1996 the researchers performed a carbon-14 analysis on organic remains discovered in the cave, including the ivory boomerang. However, at 18,000 years old, the boomerang was "unexpectedly young," raising concerns that the results had been skewed by contamination from adhesives or conservation material, the researchers wrote in the new study.

Evidence of classic Aboriginal boomerangs and throwing sticks dates back at least 20,000 years, according to the National Museum of Australia. These boomerangs are multi-use tools, often used for hunting, fighting or digging. But people around the world have fashioned throwing sticks, including one very early example from northern Germany dating back 300,000 years.

In the new analysis of finds from Obłazowa Cave, the researchers undertook DNA and radiocarbon analyses of a human finger bone from the boomerang layer and determined that the person was a modern human who lived at least 31,000 years ago. The researchers also analyzed a dozen animal bones, but not the boomerang itself, "to avoid further damage to this highly significant artifact," they wrote in the study.

A cluster of animal bones found in the same layer as the boomerang all dated to around 41,500 years ago. Given this series of radiocarbon dates and the depths of the bones within the layer, the researchers created a statistical model for the date of the boomerang, finding that it was definitely made more than 35,000 years ago and that it was most likely carved between 42,365 and 39,355 years ago.

"Our analysis on the boomerang found at the Obłazowa site has yielded groundbreaking insights into its age," the researchers wrote, positioning the boomerang "as potentially one of the oldest specimens in Europe, and possibly globally, thereby shedding light on both technical skills and cognitive advancements of Homo sapiens in crafting these complex tools."

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