Smithsonian magazine: Approximately 3.3 million years ago someone began chipping away at a rock by the side of a river. Eventually, this chipping formed the rock into a tool used, perhaps, to prepare meat or crack nuts. And this technological feat occurred before humans even showed up on the evolutionary scene.

That’s the conclusion of an analysis published today in Nature of the oldest stone tools yet discovered. Unearthed in a dried-up riverbed in Kenya, the shards of scarred rock, including what appear to be early hammers and cutting instruments, predate the previous record holder by around 700,000 years. Though it’s unclear who made the tools, the find is the latest and most convincing in a string of evidence that toolmaking began before any members of the Homo genus walked the Earth.

“This discovery challenges the idea that the main characters that make us human — making stone tools, eating more meat, maybe using language — all evolved at once in a punctuated way, near the origins of the genus Homo,” says Jason Lewis, a paleoanthropologist at Rutgers University and co-author of the study. [Continue reading…]