Shaped stone spheres were part of early humanity’s toolkit for over two million years, but what exactly they were used for has remained an enigma. Until now

Stone artifacts painstakingly shaped into spheres were part of the daily lives of early humans for more than two million years. They have been unearthed by archaeologists in East Africa, humanity’s ancestral home, and they litter prehistoric sites across Eurasia from the Middle East to China and India. Yet experts have been puzzled by their function since the early days of research into our evolutionary history.

Prehistoric shaped stone balls found at Qesem Cave, near Tel Aviv Pavel Shrago

Now, an international team of archaeologists led by Tel Aviv University archaeologist researcher Ella Assaf, has produced evidence that these enigmatic artifacts were used for a very specific purpose: breaking the bones of large animals to extract the nutritious marrow inside.

The study, published last week in the journal PLOS ONE, highlights how an elegant technological solution that allowed hominins to increase their calorie intake endured for hundreds of thousands of years and continued to be used even as our ancestors developed new techniques and created more complex societies.

The researchers analyzed shaped stone balls, also called spheroids, found in Qesem Cave, a prehistoric site just east of the modern city of Tel Aviv that was inhabited from 400,000 to 200,000 years ago. The discovery of around 30 of these artifacts in this particular cave was a puzzle wrapped in an enigma for archaeologists. Not only did the function of the spheres remain obscure, but their presence there was considered anachronistic, because these artifacts are usually found at much older sites.

Mastery of fire

Qesem Cave was uncovered during road works in the year 2000. Since then, excavations led by Tel Aviv University archaeologists Avi Gopher and Ran Barkai has uncovered a treasure trove of hundreds of thousands of flint tools and animal bones as well as 13 hominin teeth, belonging to the as-yet-unidentified group that lived at the site. 

Whoever they were, these distant ancestors of ours were relatively ahead of their time in much of the behavior they displayed, experts say. The people of Qesem Cave (whose modern name somewhat appropriately means “magic” in Hebrew) were among the first hominins to master controlled fire to cook meat, and they learned how to preserve food for a rainy day.