KALAMBO FALLS, Zambia (PNN) - September 25, 2023 - Stone Age builders may have been using other materials as well, according to a new study. Archaeologists have discovered the oldest evidence of artificial structures made of wood, dating back almost half a million years - predating the appearance of our own species and suggesting our relatives settled down much earlier than we thought.

The discovery was made at the archaeological site of Kalambo Falls in Zambia, where archaeologists found two logs joined together in an almost cross-like shape. Clear cut marks from stone tools were found on the wood, indicating they had been deliberately cut and crafted into this structure. Exactly what its purpose was remains lost to time, but the scientists speculate that it could be part of a foundation for a platform or shelter.

To determine how old the structures are, the researchers used a technique called luminescence dating. This method allows scientists to calculate when a sample was last exposed to sunlight, indicating how long it has been buried and, as such, a minimum age. When they performed this on minerals in the sand in which the logs were buried, they came up with an astonishing number - around 476,000 years old, placing it in the early Stone Age.

Previous finds have shown that early humans were making tools, weapons and other instruments out of wood even earlier, but this marks the oldest known evidence of construction with the material. In fact, it predates the existence of Homo sapiens as a species, which is thought to have evolved around 300,000 years ago. The researchers don’t speculate on which species might be responsible, but many of our ancestors and relatives were plodding around Africa at that time, including Homo erectus and Homo heidelbergensis.

One of the main reasons we don’t often see wood that old is obvious - it just doesn’t last very long. The archaeological site at Kalambo Falls helps preserve these organic materials for longer thanks to its high water levels.

The discovery shakes up our understanding of human history in other ways, too. It was long thought that Stone Age humans were nomadic, roaming around to different regions with the seasons. But building structures suggests they were settling down - and why not? The Kalambo Falls area would have been a stable source of water, while the forests around it provided ample food.

“This find has changed how I think about our early ancestors,” said Professor Larry Barham, corresponding author of the study. “Look at what these people were doing: they made something new and large from wood. They used their intelligence, imagination, and skills to create something they’d never seen before, something that had never previously existed. They transformed their surroundings to make life easier, even if it was only by making a platform to sit on by the river to do their daily chores. These folks were more like us than we thought.”

The research was published in the journal Nature.