Although stone tools get much of the attention in human evolution, ancient tools were sometimes made from other materials that do not preserve as well as stone. New research provides evidence for the oldest structural use of wood: logs used to build a structure dating to 476,000 years ago! The team excavated two interlocking wooden logs with intentionally carved notches at Kalambo Falls in Zambia, as well as other wooden objects including a digging stick, a wedge, and a chopped log. Multiple stone tools were also found at this site. The waterlogged context of Kalambo Falls allowed for unusually good preservation of organic material, including wood. While tools using a single element (flaked stone, wooden stick, etc.) are fairly common and relatively simple to construct, the invention of complex, multi-part tools, like arrowheads hafted onto spears, is much more cognitively demanding and occurs more recently in our evolutionary history. This study suggests that the first multi-part manufactured objects may have been structures or dwellings rather than butchery tools or weapons. Considering that the earliest fossil evidence for modern humans currently dates to around 300,000 years ago, this structure was likely not made by our own species.

These findings were presented in the journal Nature on September 20th, 2023, by Lawrence Barham and colleagues.