Some of the physiological characteristics that make us human can be found throughout our evolutionary history – larger brains, locking knees that allow for bipedal locomotion, etc. But what supposedly separates more modern humans is the ability to control our hands precisely, facilitating the use of tools. Now, an international team of researchers have determined that our ancestor Australopithecus africanus had the motor skills to use tools the way we do – 600,000 years before tools are believed to have existed.

As humanoid brains and legs evolved, so to did the rest of the body. As our ancestors began to spend less time climbing trees and found their hands free due to bipedal locomotion, the hands evolved from powerful, inelegant grasping tools to some of the most articulate appendages in the animal kingdom. Until now, it was assumed that the human abilities of “forceful precision” (what you’d use to turn a difficult key) and powerful gripping (used to maintain purchase on a baseball bat) evolved along with our ancestors’ ability to develop tools, about 2.6 million years ago. Australopithecus is believed to have similar capabilities, only they roamed Earth 3.2 million years ago.

For the study, the research team (which included scientists from the University of Kent, University College London, Max Planck Institute for Evolutionary Anthropology in Germany and the Vienna University of Technology) examined the spongy internal structure of the bones called trabeculae. As trabeculae tissue regenerates over time, analysis provides insight into how a set of bones was used during the individual’s lifetime.

Humans and chimpanzees, for instance, use their hands in very different ways. Chimpanzees are not able to adopt human hand postures, and their trabeculae tissue reflects this. Earlier human species, like Neanderthals, most certainly used their hands to grasp tools like modern humans, and their trabeculae tissue is more consistent with our own.

When examining Australopithecus, the researchers found something odd. Despite the accepted notion that no hominids were capable of producing tools at the time, analysis of the trabeculae in the thumb and metacarpal bones revealed evidence of forceful opposition between the thumb and fingers, a distinctly human pattern. Though it’s still unlikely that tool creation was intentional or habitual, the findings do support other studies that suggest australopiths were capable of using simple stone tools.