The Clovis people who lived in North America about 13,200 years ago have long been thought to be the continent's first tool-using humans. But the discovery of older human artefacts at a site in Texas is challenging this idea.

In sediments dating from between 13,200 and 15,500 years ago, Michael Waters of Texas A&M University in College Station and his team found 15,528 stone artefacts that seem to have been undisturbed by soil movement. This suggests that the artefacts, including ancient tools (pictured), existed before the Clovis people came to dominate the landscape. A few of the tools have similarities to Clovis ones, but are simpler and still distinct. The authors suggest that a different sort of people was using tools in North America before the Clovis people.

Credit: M. R. WATERS

Science 331, 1599–1603 (2011)