Half a million years ago, something big happened in east Africa.
It was a big enough change to transform the terrain, reshape the landscape and to alter the populations of animals living there.
And it completely transformed the early humans who lived there.
“What we are seeing is the demise of a way of life in early human ancestors that persisted for hundreds of thousands of years,” said paleoanthropologist Rick Potts, who heads the Smithsonian’s Human Origins Program.
Before the change, pre-humans such as Homo erectus had lived happily for millennia using crude, heavy stone axes. Afterwards, the early humans living in the area traded for sharp, strong obsidian and made delicate tools and spear heads. They learned to hunt new kinds of animals and they carried around a lot of raw materials for making black and red paint or ink.