Archaeologists have discovered traces of an ancient ocher-based multicomponent adhesive in 40,000-year-old stone tools unearthed in Le Moustiers, France.

“These surprisingly well-preserved tools show technical solutions that are broadly similar to examples of tools made by early modern humans in Africa, but the exact recipes reflect a Neanderthal 'spin.' “This is the manufacture of hand tool grips,” he said. Radu Iovita, researcher at New York University's Center for Human Origins Research.

In the study, Dr. Iovita and colleagues examined stone tools with traces of red and yellow colorants excavated from the French ruins of Le Moustiers, discovered in the early 20th century.

These stone tools were made by Neanderthals during the Middle Paleolithic period, between 120,000 and 40,000 years ago.

They are kept in the collection of the Museum of Prehistory and Early History in Berlin, but have not been studied in detail until now.

“The products had been individually wrapped and left untouched since the 1960s. As a result, the remains of attached organic matter were very well preserved,” says Eva, a researcher at the Museum of Prehistory and Early History in Berlin. Dr. Dutkiewicz said.

Researchers found traces of ocher and asphalt mixtures on some Mousterian stone tools, such as scrapers, flakes, and blades.

Ocher is a naturally occurring earth pigment. Bitumen is a component of asphalt and can be produced from crude oil, but it also occurs naturally in soil.

“I was surprised to find that it contained more than 50% ocher. This is because air-dried asphalt can be used directly as an adhesive, but adding so much ocher would cause it to lose its adhesive properties. '' said Dr. Patrick Schmidt, a researcher at the University of Tübingen.

Scientists tested these materials in tensile tests and other measurements used to determine strength.

“The situation was different when we used liquid bitumen, which is not very suitable for bonding. When you add 55% ocher, a malleable mass forms,” ​​said Dr. Schmidt.

It was sticky enough to pierce stone tools, and did not stick to hands, making it ideal as a material for handles.

In fact, microscopic examination of the signs of wear from use on these stone tools revealed that the adhesive on Le Moustier's stone tools had been used in this way.

“The tool showed two types of micro-wear: one is the typical grinding of sharp edges, which is usually caused by machining other materials,” says Dr. Iovita.

“Secondly, there was a bright polish distributed all over what appeared to be the hand grip, but not anywhere else. We interpreted it to be the result of wear and tear.”

The use of adhesives containing several ingredients, including various sticky substances such as tree resins and ocher, was known from early Homo sapiens in Africa, but not since early Neanderthals in Europe. It wasn't known.

Overall, the development of adhesives and their use in tool manufacturing is considered to be some of the best physical evidence of early human cultural evolution and cognitive abilities.

“Composite glue is thought to be one of the first expressions of modern cognitive processes that are still active today,” said Dr. Schmidt.

In the Le Moustiers area, ocher and asphalt had to be collected from remote locations, which required a great deal of effort, planning and a targeted approach.

“Given the overall circumstances of the find, we believe that this sticky material was created by Neanderthals,” Dr. Dutkiewicz said.

“Our research shows that early homo sapiens “African Neanderthals and European Neanderthals had similar thought patterns,” Dr. Schmidt said.

“Their adhesion techniques have the same importance for understanding human evolution.”

Regarding this research, paper Published in today's magazine scientific progress.

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Patrick Schmidt other. 2024. Ocher-based composite adhesives used in Mousterian typesetting have recorded mixed recognition and significant investment. scientific progress 10(8); doi: 10.1126/sciadv.adl0822