Archaeologists working in Africa have previously discovered hand axes made by members of Homo erectus.
In those instances, the hand axes were made by chipping bits off of stones until the edge became sharp.
But researchers in this new study found a similar hand axe, except it was instead made from bone.
The hand axe was unearthed at a dig site in Ethiopia called Konso-Gardula.
This evidence also suggests members of Homo erectus were surprisingly skilled in tool making.
The existence of such a sophisticated design is, therefore, proof ‘upright man’ was reasonably intelligent.
The archaeologists, however, remain unable to explain why the toolmaker had chosen to use bone instead of the much harder stone, despite the presence of stones on offer in the neighbourhood.
In their paper published in Proceedings of the National Academy of Sciences, the group describes finding the hand axe, their study of it and what they believe it represents.