Archaeologists reconstructed how Neanderthals manufactured sticky tar from birch bark 50,000 years ago. Neanderthals may have used the tar to attach stone points to wooden spears, as shown.

© Paul Kozowyk

50,000-year-old, tar-smeared tool shows Neanderthal smarts

Old-school scholars considered Neanderthals brutish and simple, but recent research shows they made jewelry, had a precision grip, and may have even painted cave art. Now, a tar-caked tool found on a Dutch beach supports the idea that Neanderthals could accomplish complex, multistep tasks that took planning ahead over several days.

In 2016, an amateur collector named Willy van Wingerden found a flint flake partly covered in thick black tar on the Zandmotor, an artificial beach in the Netherlands. The beach, made from sand dredged from the bottom of the North Sea, is a treasure trove of prehistoric artifacts. That’s because the sand used to be part of a wide expanse of dry, cold steppe, connecting the United Kingdom and the Netherlands during the last ice age, when sea levels were much lower than they are today.

At first glance, the tool doesn’t look like much—a small, sharp-edged flint flake with a gob of tar on the end. Once it hardened, the tar provided enough of a handhold for someone to use the flake’s sharp edge as a scraper or blade. “It looks quite simple, but it’s quite a complex tool,” says lead author Marcel Niekus, an independent archaeologist in the Netherlands who analyzed the find. “It took a lot of steps to make and haft the piece.”

When Niekus and his colleagues used radiocarbon dating to analyze the tar on the flake, they found it was 50,000 years old, dating back to a time before modern humans arrived, they write today in the Proceedings of the National Academy of Sciences.

This tar-handled tool was made by a Neanderthal 50,000 years ago.

© RMO

The tar, preserved by the cold, oxygen-free conditions in sediments several meters beneath the sea floor, might have been an essential element of Stone Age tool kits, says co-author Geeske Langejans, an archaeologist at the Delft University of Technology in the Netherlands. She and her colleagues tried to recreate tool’s manufacture, collecting strips of birch bark, mounding clay over them, and building a fire on top to heat the bark inside to 300°C–400°C for hours. The procedure was hot enough to produce thick tar, as the resinous bark disintegrated. By comparing the chemical composition of the modern tar and its impurities to the ancient tar, Langejans and her team found that the Neanderthals likely used the same procedure.

But making enough tar to adorn even an unremarkable tool was undoubtedly difficult without pottery to collect the hot, pooling tar. “It’s an ugly little piece, not even retouched or shaped,” Langejans says. “That they hafted such a simple flake suggests they used adhesives on a regular basis.” Other evidence suggests Neanderthals used pine resin and bitumen as adhesives to stick stone points to wooden spears. This find and two tarred tools from Italy and Germany suggest our extinct cousins used birch bark tar as well. The discovery also adds to previous work showing Neanderthals could engage in complex tasks, including creating finely crafted stone blades and multipart spears.

Paola Villa, an archaeologist at University of Colorado in Boulder who was not involved in the study, says it is “very good work” that shows the creators of the tools were capable of complex behavior. But, she adds, a literal handful of tools from just three sites is too few to conclude that Neanderthals used birch bark tar routinely.

Niekus hopes more finds dragged up from the bottom of the North Sea could change that: “This is the tip of the iceberg,” he says. “Beneath the sea, there’s a lot of sites, and thanks to beach replenishment we can study them.”