For centuries, Germany’s Unicorn Cave has been a lure for people seeking secrets from the past. In the Middle Ages, people literally mined the site for mammoth tusks, cave bear teeth, and the remains of other extinct animals. The unfamiliar skeletons were thought to belong to legendary beasts—dragons, perhaps, or unicorns. Powdered and mixed with gold and silver, these mysterious bones were considered cure-alls for everything from impotence to the plague.
About the size of a chess piece, it was carved with 10 deep, slanting lines on one side. Russo, a University of Tübingen archaeozoologist who specializes in identifying animals from the distant past based on their bones, immediately recognized it as a phalange—more precisely, the second knuckle bone of a large hoofed animal. On closer examination, he noticed something odd: The cuts didn’t look like the hacking of a butcher trying to extract meat or marrow. These marks appeared intentional, like an abstract pattern or decorative design.
When archaeologists Thomas Terberger of the University of Göttingen and Dirk Leder of the Lower Saxony State Office for Cultural Heritage, who direct excavations at Unicorn Cave, saw the incised knuckle bone, they were impressed but not surprised. Research in and around the cave since 2014 has turned up ample tools and artifacts showing that its caverns were used by early modern humans and their Neanderthal ancestors. The archaeologists assumed the bone was a decorative piece carved by an Ice-Age human, not a Neanderthal, and that radiocarbon dating would likely support their assumption.
Then the dating results on the mysterious bone came back from the lab.
In a paper published today in the journal Nature Ecology and Evolution, an international team of researchers report that radiocarbon dating shows the carving is at least 51,000 years old, meaning it was created at least a thousand years before modern humans arrived there. (Modern humans are believed to have entered this part of Europe no more than 45,000 to 50,000 years ago.)
The authors argue the bone could have been carved only by Neanderthals, and that it represents the first time Neanderthal symbolic expression—some call it art—has been directly dated. The discovery gives researchers reason to reevaluate the old assumption that Neanderthals were incapable of creativity or complex thought.
“It’s an idea, a planned motif that you have in your mind and translate into reality,” Terberger says, referring to the pattern on the bone. “It’s the start of culture, the start of abstract thinking, the birth of art.”
But is it art?
As anyone familiar with arguments about abstract painting and modern art knows, “art” is in the eye of the beholder. For many, it’s a distinctly modern concept—something with symbolic meaning to the maker and the audience, made to be enjoyed or appreciated for the way it looks. The definition of art can shift from culture to culture, and even decade to decade.
That makes it tricky to talk about what Neanderthals were hoping to achieve when they carved a design on a piece of bone. “Today, we usually mean art in a visual, aesthetic sense, and we don’t know if that’s what was meaningful to them,” says Amy Chase, a paleoanthropologist at Memorial University of Newfoundland who did not participate in the research. “It’s difficult to label something made 50,000 years ago with our own concepts.”
Symbolic expression, on the other hand, is easier to recognize and agree on. From the choice of animal species to the orientation of the cut lines—angling upward when you set the bone on its flat, stable end—the long-gone carver of the Unicorn Cave bone was making deliberate choices that seem to have had specific meaning. “It’s the first step towards art,” Terberger says. “When you’re communicating with complex design and symbols, you are at the border of what we would call art—or already there.”
A deliberate creation
Credible evidence for anything that could be called Neanderthal “art”—even simple doodles—is incredibly rare. This fact has led generations of researchers to conclude our distant relatives were uninterested in symbolic or decorative representations at best, and incapable of creative thinking at worst.
And what scant evidence there is—geometric decorations on a cave wall in Spain, eagle talons buried with dead Neanderthals in Croatia—hasn’t been directly dated. Instead, archaeologists have relied on estimates based on the ages of bones found nearby, or on chemical analyses of cave walls, leaving room for doubt as to the object’s true age.
While a direct radiocarbon date from the incised bone left no question as to the artifact’s age, researchers also tried to replicate the carvings to ensure that the marks weren’t the accidental byproduct of butchering, or idle scratches by a bored Neanderthal killing time by the campfire.
The bone belonged to a giant deer, Megaloceros giganteus, a behemoth that stood seven feet at the shoulder, weighed as much as a small car, and was rarely found north of the Alps. Giant deer went extinct more than 7,000 years ago, so Leder and University of Göttingen experimental archaeologist Raphael Hermann sourced fresh cow bones—a close match—and replica flint blades.
After weeks of experimentation, they determined that the carvings were best replicated on bone that was repeatedly boiled and dried, and that each cut took at least 10 minutes to carve and used up one or two valuable flint blades. “A lot of process and thinking went into this,” says Hermann.
“If you take the time to modify bone with a non-utilitarian motif, you’re doing it for some reason. Some Neanderthal took the time to carve these patterns into a deer phalange, and that was intentional,” says Kenyon College archaeologist Bruce Hardy, who was not involved with the research. “If you add it to the other evidence, you’re seeing accumulating evidence for symbolic behavior.”
John Shea, an archaeologist at Stony Brook University in New York, disagrees, and suggests the Unicorn Cave bone could be a sinker for a fishing line, a spool for thread, or some other utilitarian tool we’re unfamiliar with at a remove of 50,000 years. “That one cannot identify the function doesn’t mean the object is a symbol,” Shea says. “With a couple minutes of thought, there are alternatives to the symbolic interpretation.”
“When humans use symbols, they show up all over the place,” he adds. “Neanderthals are doing something different, if they are using symbols at all.”
Artists or just ‘capable copycats'
Further complicating matters is the fact that modern humans and Neanderthals, however briefly, overlapped in time and space. Because some of the finds researchers have identified as Neanderthal symbolic expression or art seem to date from right around the time humans arrived on the scene in Europe, researchers have argued Homo neanderthalensis were just capable copycats, reproducing and imitating the creative output of their newly-arrived Homo sapiens cousins rather than creating art or symbols of their own.
The Unicorn Cave find, however, predates the arrival of modern humans in Europe, making it a distinctly Neanderthal object, researchers assert. (An accompanying essay by paleoanthropologist Silvia Bello in Nature Ecology and Evolution, however, notes recent genetic evidence that points to an earlier arrival of Homo sapiens in Europe, and says the possibility that the artifact was indeed influenced by modern humans, albeit remote, should not be rejected.)
Even Terberger admits, however, that there’s a huge gap between the creative output of modern humans and that of Neanderthals. “For early modern humans, objects like this are a normal part of their material culture,” he says. “For Neanderthals, they only produced such items from time to time. There are thousands of Neanderthal sites worldwide, and about 10 where we can talk about artistic expression."
Digging Unicorn Cave
The cave likely owes its name to the 17th-century scientist Gottfried Leibniz, who reconstructed an odd-looking “unicorn” out of a cave bear skull and wooly mammoth tusks and vertebrae from the site—a monstrous mash-up that that has become the cave’s mascot. In a typical year, 30,000 visitors file through the cool, vaulted halls of Unicorn Cave, which is located inside Germany’s largest UNESCO Geopark. It’s been used for fashion shoots and as a set for film and TV (including the Netflix series “Dark”) and the occasional gothic metal music video.
The most recent search for evidence of the cave’s deep past began in the 1980s, when paleontologist Ralf Nielbock convinced the local cooperative that owns the cave to let him open it as a tourist attraction. While enlarging dirt pathways inside the cave for anticipated visitors, he found unusual tool-shaped stones that convinced him Neanderthals once dwelt in the cave, but lack of funding forced him to pause his initial excavations for nearly two decades.
In 2014, Nielbock reached out to researchers at the nearby University of Göttingen to see if they’d be interested in excavating. Terberger and Leder brought in a team of archaeologists to focus on the original entrance to the cave, which collapsed around 10,000 years ago.
Soon one team was working its way in from the outside as another worked deep inside the cave, excavating in a tunnel-like space that once was part of the cave mouth. In 2019, they began finding stone tools and animal bones—including the curiously carved deer bone—dating back 50,000 years or more, a time when the area was free of glacial ice.
Last summer, Russo found more of the giant deer’s remains, along with the bones of a few red deer and bison. But so far, the team has found no direct evidence—such as campfires or burned bones in the layer around the carved bone—that Neanderthals occupied the site.
One possibility is that the cave was used for a very short period of time, to drag the carcass there and extract the meat, Russo says. But the excavations are in early days, and they have found bits of charcoal nearby, so future work might uncover the remains of a campsite or rock shelter in the wreckage of the collapsed cave.
A variety of evidence from the Unicorn Cave excavations, including animal bones and pollen, indicate that Neanderthals living there would have been on the frontier of habitable Europe. To the north was trackless ice and snow, and winters would have been cruel. Different mixes of plants and animals over time suggest an unpredictable climate.
“This period of climatic instability is when the piece was made,” Leder says. “Within this time frame, we have really quick changes, from forests to more open, reindeer-favoring environments.”
“Neanderthals here are at their northern limits, and also dealing with shifting environmental conditions,” he adds. “That might have forced them to become more dynamic and creative.”
Combined with other evidence, the Unicorn Cave bone builds the case for Neanderthals having a rich inner life of their own.
“This is a significant find,” paleontologist Chase says.
“It has the ability to shift the field away from a constant comparison of what they could do compared to modern humans, and let the Neanderthals be the main characters in their own story.”