Humans lived in South America at the height of the last ice age, thousands of years earlier than we thought, according to a controversial study. A team claims to have found 22,000-year-old stone tools at a site in Brazil, though other archaeologists are disputing the claim.
Christelle Lahaye of Michel de Montaigne Bordeaux 3 University in France and colleagues excavated a rock shelter in north-east Brazil and found 113 stone tools.
The team dated the sediments in which the tools were buried using a technique that determines when the sediments were last exposed to light. Some tools were buried 22,000 years ago – thousands of years earlier than any known human colonisation of the Americas.
For decades, archaeologists thought that the Clovis people were the first to enter the Americas, 13,000 years ago. But since the 1980s evidence has accumulated for an earlier colonisation, at least 15,000 years ago.