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. 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...