So much of modern-day life revolves around using opposable thumbs, from holding a hammer to build a home to ordering food delivery on our smartphones. But for our ancestors, the uses were much simpler. Strong and nimble thumbs meant that they could better create and wield tools, stones and bones for killing large animals for food. Because developing dexterous, opposable thumbs pushed our ancestors to make and use tools, eat more meat and grow bigger brains, scientists have long wondered if such thumbs began only with our own genus, Homo, or among some earlier species.
Now a new study combines the ancient evidence of fossil fingers and thumbs with cutting-edge computer muscle modeling to conclude that South African hominins boasted flexible, capable thumbs much like ours as far back as two million years ago. “It is remarkable that such a level of thumb dexterity, similar to that of people living today, would be observed in hominins alive two million years ago,” says Katerina Harvati, a paleoanthropologist at the Senckenberg Center for Human Evolution and Paleoenvironment, University of Tübingen (Germany).