Historical archaeological websites throughout the Northern Hemisphere have been suffering from a thriller. The place there have been hominins, there too may usually be discovered roughly rounded spheres of stone. Some have been dated again to over 2 million years in the past, with marks suggesting that the balls had been intentionally formed.
New analysis has found a believable goal for these unusual instruments: Our ancestors may have been utilizing them to smash open bones – to get to the nutritious marrow inside.
A world crew of researchers led by archaeologist Ella Assaf of Tel-Aviv College in Israel made a detailed examination of ten such stones discovered at Qesem Cave, a Decrease Paleolithic website occupied by early people between 400,000 and 200,000 years in the past.
That is curious, as a result of it is the newest identified look of those instruments, a timeframe when different communities had way back stopped utilizing them. So Assaf and her crew investigated to search out out extra about these stones, and the way they obtained there.
Not solely did they discover proof supporting the stones’ use in bone marrow extraction on the stone artefacts themselves, they smashed open bones with replicas to find out their efficacy. Spoiler: bones had been smashed, marrow extracted.
“We current new outcomes from Center Pleistocene Qesem Cave on the usage of these implements as percussion instruments,” the researchers wrote of their paper.
“As bone marrow performed a central position in human vitamin within the Decrease Paleolithic, and our experimental outcomes present that the morphology and traits of formed stone ball replicas are well-suited for the extraction of bone marrow, we advise that these options may need been the explanation for his or her assortment and use at Qesem Cave.”
The crew took a double-pronged method to finding out the aim of the balls.
First, they totally examined 29 historical balls discovered within the cave. These should not completely rounded stones, however have tough ridges the place flakes have been knapped away.
All however one in every of them – one was flint – had been made out of dolomite or limestone distinct from different rocks discovered within the space, and so they had a unique patina from different instruments discovered within the cave. This implies the stone balls had been saved in a unique atmosphere for a while earlier than ending up at Qesem Cave.
That is attention-grabbing, as a result of it’s according to earlier findings on different instruments within the cave. Whoever the inhabitants had been, they’d a behavior of discovering instruments elsewhere and bringing them dwelling for their very own use. In different phrases, they recycled.
Of those 29 stone balls, 10 retained traces of use-wear and residue, so the crew performed digital stereomicroscopy and metallographic microscopy to look at them extra intently. They analysed residues discovered within the marks related to the use-wear, and made an attention-grabbing discovery.
“Archaeological residues have morphological options, look, color, and distribution suitable with compact and spongy bone, natural bone shiny movie, collagen fibers, and animal fatty issues noticed on experimental stone balls utilized in bone marrow extraction actions,” they wrote of their paper.
“Specifically, on the highest of the distinguished ridges, residues seem as spots of natural movie with a shiny and sometimes striated look. They coexist with spots of crushed amorphous white residues according to bone fats and collagen fibers typically additionally smeared and crushed onto the instruments’ scars.”
That brings us to the second prong. Based mostly on the use-wear scars and residue patterns, the crew first knapped their very own balls out of various sorts of rock, then examined them on cow and sheep bones. Additionally they examined naturally formed easy stones.
And so they discovered that the replicas of the Qesem Cave stones had been probably the most environment friendly at cracking open bone to get to the marrow therein, and that the ridges assist crack the bone in a clear break.
This implies that the cave inhabitants had been sensible sufficient to know factor once they noticed it. Why carry out the arduous work of creating a brand new software when a superbly advantageous one was out there?
This additionally matches up with analysis printed final yr. One other crew of researchers introduced proof that bone marrow was an important a part of the weight loss program of the unknown hominins who inhabited Qesem Cave – so necessary that they’d retailer it for as much as 9 weeks, to maintain a wealthy meals supply out there for later consumption.
So not solely do we all know that bone marrow was deeply necessary to the inhabitants of the Qesem Cave, we additionally know that they had been fairly savvy when it got here to meals sources.
“These outcomes make clear the operate of formed stone balls and are according to the importance of animal fats within the caloric consumption of Center Pleistocene people as proven by the archaeozoological proof at Qesem Cave and probably past,” the researchers wrote.
However as to what the balls had been used for earlier than they got here to Qesem Cave? Nicely, that is nonetheless an enormous outdated thriller ready to be solved.
The analysis has been printed in PLOS One.