Neanderthal glue from the North Sea
A flint tool covered with a tar-like substance has turned out to be a top scientific find. Research by a Dutch team of scientists showed the find to be a piece of birch tar that was extracted 50,000 years ago by Neanderthals using complex techniques. The tar was used as an adhesive to make it easier to hold the piece of flint. Details of the find have been published in the Proceedings of the National Academy of Sciences (PNAS).
Knowledge of chemistry
Dating back 50,000 years means that the artefact is older than the period when modern man inhabited Europe and that it must have been used by a Neanderthal. Chemical analysis has shown that the substance is birch tar. There are different ways - some simple, some more complicated - of extracting tar from birch bark, all requiring a basic knowledge of 'chemistry' to be able to carry out the necessary steps in the right order. CT scans of the tar and chemical analysis show that a complex technique was used, including heating the material in a kind of oven.
Knowledge economy
Leiden archaeologists were involved in the research. Gerrit Dusseldorp explains the discovery: ‘This find shows that Neanderthals placed a lot of emphasis on "high-tech" methods, even on the periphery of their inhabited territory. When the North Sea dried up during the last Ice Age, they turned to the knowledge economy to survive the barren environment.'
Paul Kozowyk, whose PhD research is on prehistoric adhesives, is also enthusiastic. 'What is so interesting about this find is the combination of a large amount of birch tar on a small and simple sliver of stone. It shows that Neanderthals were not only skilled in making tar, but that they also invested in materials that are all too easily to overlook in archaeological research.'
Importance to science
This artefact is of exceptional scientific importance. In the whole of Europe there are only two known sites where tools with birch tar have been found. Gerrit Dusseldorp is delighted with the find.
'A top find from the Netherlands! Almost all the sites that I learned about when I was a student are in foreign countries. That makes it a real privilege to be part of a team that analysed a new top artefact from the Neanderthal period found in the Netherlands.'
The other two sites are Königsaue in Germany and Campitello in Italy. The tar remnants from Campitello are 200,000 years old, making them the oldest known examples. The tar at all three sites seems to have been produced in a similar way, indicating that Neanderthals systematically invested a lot of time and energy in making composite tools.
The evolution of complex technologies is often associated with living in large groups at a fixed location. This is by no means typical of Neanderthal communities; Neanderthals generally lived in small, mobile groups. According to the researchers, during the Ice Age Neanderthals in Europe invested in technology to reduce the ecological risks, such as food shortages.
Annemieke Verbaas conducted microscopy research on the object: ‘Even using a microscope, the artefact was too far eroded to be able to identify traces of use, so the purpose of the tool remains a mystery.'
Sand Motor
The tool was found in 2016 on the Sand Motor, a stretch of artificial sandbank off the coast of The Hague, and originated from the North Sea. During the Ice Age this was an inhabited lowland area, where Neanderthals lived in what were often harsh conditions. By applying high-quality knowledge and complex techniques for making tools, they were able to cope better with hardships such as cold and food shortages.
National Museum of Antiquities
The flint tool with traces of birch tar can be seen in the central hall of the National Museum of Antiquities in Leiden until Sunday 12 January 2020.