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The Deep Cave Structures Left Behind by Neanderthals

New research suggests that Neanderthals began exploring deep cave environments earlier than previously thought.

By Kate Wheeling


Bruniquel Cave. (Photo: Wikimedia Commons)

Less than a quarter mile into the Bruniquel Cave in southwest France, broken stalagmites stand in ring-like structures on the cavern floor. The regular pattern of the cave growth pieces, and the traces of fire visible on their surface, hint that the rings may have been man-made. A new study, published today in Nature, suggests that cave-dwelling Neanderthals arranged the structures.

“The ability of Neanderthals to appropriate the ‘underworld,’ to venture so far underground, and with proper lighting — it changes very seriously our knowledge about Neanderthal people,” says Jacques Jaubert, a professor of prehistory at the University of Bordeaux in France, and lead author on the new study.

The entrance to the Bruniquel Cave collapsed sometime during the Pleistocene period, which stretched from roughly 11,000 to 2.6 million years ago, and was re-opened less than three decades ago, leaving the cave structures remarkably well preserved. The structures are made of nearly 400 similarly sized stalagmite pieces — further evidence that humans had a hand in arranging the columns into two large rings and four smaller assemblies — weighing in at approximately 2.4 metric tons in total.

“It changes very seriously our knowledge about Neanderthal people.”

Reddened, blackened, and charred fragments suggest the structures were exposed to fire — a finding supported by chemical analyses. Constructing the arrangement would likely require social organization to design, transport, and place the stalagmites, according to the authors, as well as sufficient natural lighting to carry out those tasks in the dark depths of the cave.

Dating the stalagmite pieces, the researchers found the materials to be between 175,000 and 177,000 years old — when Neanderthals were the only humans living in the region.

The study provides some of the first evidence that Neanderthals frequented caves at depths beyond the reach of sunlight. But just because Neanderthals explored deep cave sites like Bruniquel doesn’t mean they actually lived there, according to Jaubert. “These are two very different things,” he says.

The function of the structures is still a mystery. “We can only proceed by deduction,” Jaubert says. There is little evidence that Neanderthal people were living in the cave, or that the structures had a food-related purpose, he notes. Might they have been part of some ritual behavior? In the future, Jaubert and his colleagues plan to continue their study of Bruniquel to shed more light on the function of the mysterious structures.