Archaeological adhesives made from Podocarpus document innovative potential in the African Middle Stone Age

Glue manufacturing goes back a long way

31 January 2023

Humans in Africa were producing glue back in the Middle Stone Age, about 100,000 years ago.

Many animals use and manipulate objects found in nature, but humans employ sophisticated processes to produce new materials. Anthropologists are interested in tracing how far back this ability goes.

Now, a team led by a researcher from the University of Cape Town in South Africa has found evidence that people in the Middle Stone Age manufactured glue from the leaves of a conifer tree found in Africa.

The researchers proposed two processes that could have been used: burning the leaves and collecting the tar on a stone, and a more elaborate process that involves distilling the tar underground for several hours.

Importantly, unlike resins exuded from many trees, the leaves themselves are not sticky. But the tar obtained from them has superior adhesive properties.

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References

1. PNAS 119, e2209592119 (2022). doi: 10.1073/pnas.2209592119