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Reconstruction of a stone artifact with a handle made of a bitumen-ocher mixture

Photo: Illustration: Daniela Greinert / Museum of Prehistory and Early History; Photo: Patrick Schmidt / Museum of Prehistory and Early History

At the beginning of the 20th century, the Swiss archaeologist Otto Hauser worked at the famous Le Moustier site in France. There he recovered stone tools in a layer from the middle Paleolithic period, which were initially not examined in detail and are now in a collection in Berlin. Only now have experts discovered their scientific value.

Remains of an adhesive that is over 40,000 years old cling to the objects. “The collection items were individually packaged and untouched since the 1960s,” says Ewa Dutkiewicz from the Museum of Prehistory and Early History at the Berlin State Museums in a statement. “As a result, the adhering remains of organic substances were very well preserved.” A study in the journal “Science Advances” now reports on the find.

The adhesive consists of ocher, a naturally occurring earth pigment, and bitumen, a hydrocarbon mixture. The two raw materials apparently had to be collected from places far apart in the Le Moustier region - that meant a lot of effort, planning and a targeted approach.

“Taking into account the entire context of the find, we assume that the elaborately produced adhesive material was made by Neanderthals,” says Dutkiewicz. The Neanderthals first used the Le Moustier cave around 120,000 years ago. About 40,000 years ago, the relatives of anatomically modern humans died out.

According to the scientists, this is the earliest discovery of a multi-component adhesive in Europe to date. Previously, glues with several components, such as tree resins or ocher, were known from early modern humans, Homo Sapiens, in Africa.

Stone artifacts will be on display

The Neanderthals used the glue to provide handles to stone tools, such as scrapers and blades. With the right mixing ratio, the material is just sticky enough for a stone tool to get stuck in it, but your hands stay clean - a "sophisticated mixture," they say.

According to the researchers, developing adhesives and using them to produce tools is considered one of the best material evidence of the cultural evolution and cognitive abilities of early humans. “This discovery,” says Patrick Schmidt from the University of Tübingen, “is of great importance for our understanding of incarnation.”

In the permanent exhibition on the Stone Age in the New Museum in Berlin, visitors can see the skull of a young Neanderthal that was once found in Le Moustier. The plan is to integrate the stone artifacts from the current study into the exhibition.