As the Ice Age waned, melting glaciers drowned the territory of Doggerland, the ground that once connected Britain and mainland Europe. For more than 8,000 years, distinctive weapons—slender, saw-toothed bone points—made by the land’s last inhabitants rested at the bottom of the North Sea. That was until 2oth-century engineers, with mechanical dredgers, began scooping up the seafloor and using the sediments to fortify the shores of the Netherlands. The ongoing work has also, accidentally, brought artifacts and fossils from the depths to the Dutch beaches.
Fossil-hunter hobbyists collected these finds, amassing nearly 1,000 of the jagged bone weapons, known to archaeologists as Mesolithic barbed points. Not only known from the North Sea, barbed points have been found at sites from Ireland to Russia, dating between 8,000 to 11,000 years ago, when the last foragers inhabited Europe before farmers arrived. Mesolithic people likely fastened the points to longer shafts to make arrows, spears and harpoons, key for their hunting and fishing livelihoods. But scholars mostly ignored the barbed points dotting Dutch beaches because they weren’t recovered from systematic digs of proper archaeological sites, like the barbed points found in the U.K. and continental Europe.
Now a team, led by Leiden University archaeologists, has analyzed some of the washed-up weapons, performing molecular measurements to determine which species the barbed points were made from. The scientists mainly wanted to test if this kind of analysis, which depends on proteins surviving in bone, was even possible for artifacts buried underwater for millennia. Not only did the method work, it delivered shocking results: While most of the roughly 10,000-year-old points were made of red deer bone two were fashioned from human skeletons.
“As an expert in this field, I really wasn't expecting that. It's really cool,” says Newcastle University archaeologist Benjamin Elliott, who was not involved in the research. Never before have archaeologists found unambiguous evidence that ancient Europeans carefully crafted human bones into deadly weapons.
The study scientists puzzled over why Mesolithic people used red deer and human skeletons for their weapons. “What’s going on with these points?” says Virginie Sinet-Mathiot, an anthropologist at the Max Planck Institute in Leipzig, Germany, who worked on the project. “What does it mean?”
Practical or economic concerns seemed unlikely explanations: Other raw materials like antler would have been more readily available and durable. Rather, the researchers concluded that ancient hunters chose these particular bones for symbolic reasons, related to their social or spiritual beliefs.
“This was not an economic decision,” says archaeologist Joannes Dekker, lead author of the study, forthcoming in the Journal of Archaeological Science: Reports. The economic move would have been for ancient hunter-gatherers to produce strong points, quickly from animal parts leftover from meals. In that case, researchers would expect to find points made from antler as well as bones of aurochs, other deer species and Eurasian elk. These creatures roamed Mesolithic Doggerland, and experiments by modern archaeologists have shown their bones make excellent projectile weapons.
The fact that the scientists found predominately red deer and human bones suggests, “There must have been some other reason, a cultural reason, why it was important to use these species,” says Dekker, a Masters student at Leiden University in the Netherlands.
The specific motivations driving this Doggerland fad, though, remain a mystery. “You can measure modern bone to see its properties as a projectile point,” says Dekker. “You can't measure the thoughts in the head of a Mesolithic hunter-gatherer.”
Still, knowing Mesolithic people used human bones this way is a major discovery. “The human stuff is a complete shock,” says Elliott.
According to him, earlier researchers had floated the idea that human bone comprised some especially long barbed points found in Ireland. Those speculations were based on the fact that there weren’t many large mammals, besides humans, on the island back when the artifacts were made. But until recently, no technology existed to test those claims.
Generally, archaeologists can eyeball a bone, and based on its size and contours, know the body part and animal type from which it came. But that’s nearly impossible for barbed points because the identifying features have been whittled and worn away through manufacture, use and burial.
Over the past decade, a new technology has been developed that solves this problem. The method, Zooarchaeology by Mass Spectrometry or ZooMS, detects the molecular building blocks of collagen, the main protein in bone. Because these collagen components differ slightly between animal types, measuring them can indicate the species of a bone—even for skeletal bits or sculpted artifacts that can’t be identified by visual features.
During ZooMS, scientists chemically dissolve a dash of powdered bone to extract collagen molecules, which are run through a measurement instrument. The method has proven handy for distinguishing between bones of similar-looking creatures like sheep and goat, or rat and mouse. And for Stone Age sites, the process has been used to scan thousands of matchstick-sized skeletal pieces to find rare Neanderthal, Denisovan and Homo sapiens specimens among heaps of animal bones. Since its introduction in 2009, ZooMS has been successfully used on remains from dozens of sites worldwide, dating from the Stone Age to modern times.
But scientists questioned whether the method would work on Mesolithic Doggerland points; millennia under the sea may have destroyed the collagen proteins. “The challenge here was would we be able to extract collagen and to perform species identifications from material that had been submerged in water for such a long time,” says Sinet-Mathiot, who works to innovate ZooMS protocols through her research.
In 2018, Dekker decided to try, in a small project for his bachelor’s thesis in archaeology at Leiden University. Dekker got permission from a dozen collectors to scrap or chip a bit of bone from their barbed points. He brought the samples to the Max Plank Institute in Leipzig, Germany and worked with Sinet-Mathiot to run the ZooMS analysis. Collaborators at the University of Groningen measured radiocarbon dates, confirming the artifacts were Mesolithic age.
For scholars of European prehistory, the new results are tantalizing, but present more questions than answers. Because the study only tested ten points, washed ashore, scientists don’t know how often, and under what circumstances, people armed themselves with human bones. “It's super interesting that they found two humans in there, out of ten analyzed in total,” says Theis Zetner Trolle Jensen, a postdoctoral researcher at the University of Copenhagen, who was not involved in the study. “But it might very well be that they found the needle in the haystack.”
Earlier this year Jensen and colleagues published a much larger ZooMS study, which determined the animal types comprising 120 Mesolithic barbed points recovered from peat bogs of Denmark and Sweden. They found bones from red deer, moose, bovine and a few brown bear—but not one from Homo sapiens. And, they concluded the Mesolithic crafters chose bone types with preferable mechanical properties. The hunters picked their mediums for practical reasons, not cultural considerations.
The differing results raise the possibility that only inhabitants of Doggerland turned human bones into deadly points during the Mesolithic. “It might be that there are strange people there… people that did different things,” Jensen says.
He and other scholars hope these questions will be clarified through more ZooMS work of barbed points. Although the new study analyzed a small number of artifacts, it showed the scientific value of artifacts washed onto Dutch shores.
“Ideally we’d love [the artifacts] to come from securely excavated contexts,” says Elliott. But Doggerland sites lie beneath the North Sea, so out-of-context beach finds offer invaluable, accessible evidence. “We can’t be snobby about it,” he says. “We have to really embrace it and try to get as much information and understanding from those artifacts as we possibly can.”
Everyday more fossils and artifacts appear on Dutch beaches, enticing a growing number of collector hobbyists. The Facebook group for this community now includes some 600 members, according to its moderator Erwin van der Lee of Rotterdam. “The competition is also very large,” he says.
Rick van Bragt, a university student in The Hague, has found about 10,000 ancient items since he began searching nearly ten years ago. Van Bragt and van der Lee entered their barbed points in the ZooMS study. While van der Lee’s artifact failed to produce results, van Bragt’s point was identified as red deer from 8,000 years ago. Both collectors were fascinated by the news that human bone formed two of the points.
Beyond bone points, the tides washing over Dutch beaches drop shark teeth, flint tools made by Neanderthals, fossils from long-extinct mammoths and other treasures. Spotting the finds takes practice though, and most beachgoers are unaware of what’s there. In the summer, “there’s a lot of people on the beach and they just step on everything,” says Van Bragt. “They don’t see it.”
Editor’s Note, December 21, 2020: This article mistakenly stated 21st-century engineers dredged the seafloor; it was 20th century engineers that started the work.