Monkeys using stones to crack open nuts generate many stone flakes accidentally that look exactly like the ones archaeologists have long thought early humans made intentionally as tools. Oops.
The discovery suggests an earlier start to the Middle Stone Age in Africa than previously documented. It also offers clues to early social networks and symbolic art by human ancestors.
Scientists have found stone tools in India dating back to 385,000 years ago. The sharp tools were made with a Stone Age technique thought to have originated in Africa and Europe.