Stone Age builders may have used other materials, according to a new study. Archaeologists have discovered the oldest evidence of wooden man-made structures dating back nearly 500,000 years - predating the emergence of our species, suggesting our relatives settled earlier than we thought.
The discovery was made at the Kalambo Falls archaeological site in Zambia, where archaeologists found two logs joined together in an almost cross-shape. Obvious stone tool cut marks were found on the wood, indicating that they had been deliberately cut and worked into this structure. Its exact purpose has been lost to time, but scientists speculate that it may have been part of the foundation of a platform or shelter.
To determine the age of these structures, the researchers used a technique called "luminescence dating." Using this method, scientists can calculate when the sample was last exposed to sunlight, and thus how long it was buried, and thus the minimum age of the sample. When they tested the minerals in the sand where the logs were buried, they came up with an astonishing figure - about 476,000 years old, placing it in the early Stone Age.
Previous finds have shown that early humans were making tools, weapons and other implements from wood even earlier, but this is the oldest known evidence of building with wood. In fact, this predates the emergence of the species Homo sapiens, which is thought to have evolved about 300,000 years ago. Researchers haven't speculated on which species might have been responsible, but many of our ancestors and relatives were roaming around Africa at the time, including Homo erectus and Homo heidelbergensis .
We don’t often see wood that’s that old, and one of the main reasons is obviously that wood doesn’t live very long. Due to the higher water levels, the archaeological site at Calambo Falls helps preserve these organic materials for a longer period of time.
The discovery upends our understanding of human history in other ways as well. Stone Age humans have long been thought to have been nomadic, wandering from region to region as the seasons changed. But building buildings shows they were settled - and why not? The Calambo Falls area is a steady source of water, while the surrounding forest provides ample food.
Professor Larry Barham, the corresponding author of the study, said: "This discovery changes my view of our early ancestors. Look at what these people were doing: they made something new and big out of wood. They used their intelligence, imagination and skills to create something they had never seen before, something that had never existed before. They transformed their surroundings to make life easier, even if it was just a platform by the river to sit on and do daily chores. These people were more like us than we think."
The research was published in the journal Nature. The researchers describe the findings in the video below.