We tend to think that ancient humans were constantly on the move, but at a site in Zambia there are the first tentative hints that people stayed put and built large wooden dwellings
By Colin Barras
20 September 2023
A flint was used to shape this log identified at the archaeological site Kalambo Falls in Zambia
Larry Barham, University of Liverpool
Ancient humans were building large wooden structures – possibly houses – almost half a million years ago. The discovery, the earliest evidence of wooden construction, suggests that some ancient communities were far less nomadic than we have assumed.
“These people were behaving in ways I hadn’t expected,” says Larry Barham at the University of Liverpool, UK. “It’s a disruptive discovery.”
Barham and his colleagues uncovered the evidence at Kalambo Falls, an archaeological site in Zambia. In 2019, they spent a month excavating a sandbar some 300 metres upstream of the falls.
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One of the first artefacts they found was a wooden tool, probably a digging stick. “The number of sites where wood is preserved is small,” says researcher Geoff Duller at Aberystwyth University, UK.
As they continued to dig, they made another discovery: a 1.4-metre-long log overlying an even larger log that was too big to fully excavate during their month-long project. They saw that the overlying log had been worked with tools to fashion a deep notch midway along its length. This allowed it to interlock with the underlying log at a 75-degree angle, creating a relatively sturdy joint. The researchers speculate that the two interlocking logs were once part of a larger wooden structure.
Duller then dated the artefacts using a technique called post-infrared infrared stimulated luminescence. This involves measuring the time since the mineral grains in the sand that surrounded the wood were last exposed to light prior to their burial. The mineral grains – and the artefacts they surround – were buried about 476,000 years ago, which implies that the wooden structure was built before our species evolved. The engineers therefore belonged to an earlier human species, possibly Homo heidelbergensis.