Prehistoric Stones Used As Weapons, UW Professor Finds

Aug 24, 2016

Qin Zhu with spheroids.
Credit University of Wyoming

A UW professor has co-authored a study that shows a nearly two-million-year-old grinding tool might have actually been used as a weapon.

For years, scientists  have believed round stones, called spheroids, were used by early humans to grind and shape other objects. Spheroids have been found in archaeological sites in South Africa and elsewhere. Archaeologists believe they date back as far as the Early Stone Age, nearly two million years ago.

In this study, Qin Zhu and  his colleagues used simulations to demonstrate that the spheroids are optimal for throwing. Zhu says it seemed natural to join archaeology with his discipline of kinesiology. "You know, why don't we just collect those data on the size and the weight of those spheroids they found," Zhu says, "and then put it into the simulation we used previously for throwing, and calculate the impact and the damage that could be inflicted by those objects."

Zhu says that the study successfully tested the stones against simulations of medium-sized animals, like antelope.  

Zhu says the study raises new questions. "We could actually use the same idea to simulate the throwing and to predict the damage index for other shape stones, not necessarily round or spherical, and also is it possible to predict the damage on different sizes of animals?"

According to the study, throwing is a uniquely human skill. Spheroids could have been one of the earliest tools humans used to hunt.