Add Yahoo as a preferred source to see more of our stories on Google. Stone tools are deliberately made by the hands of hominins, like these worked on by the author. John K. Murray Have you ever found ...

When monkeys in Thailand use stones as hammers and anvils to help them crack open nuts, they often accidentally create sharp flakes of rock that look like the stone cutting tools made by early humans.

Our prehistoric human ancestors relied on deliberately modified and sharpened stone tools as early as 3.3 million years ago.

Have you ever found yourself in a museum's gallery of human origins, staring at a glass case full of rocks labeled "stone tools," muttering under your breath, "How do they know it's not just any old ...