SCIENCE

Rings of stalagmites found in a cave in France suggest that our ancient relatives were surprisingly skilled builders. (Nat Geo News)

Use our resources to better understand exploration of mysterious caves.

Teachers, scroll down for a quick list of key resources in our Teachers Toolkit.

Discussion Ideas

• The Nat Geo News article reports that a cave in southern France may hold remnants of a structure created by our Neanderthal relatives more than 175,000 years ago. The structure is made of stalagmites. What are stalagmites?
  • A stalagmite is a mineral deposit formed on a cave floor, usually by mineral-rich water dripping from above.
    • Stalagmites and stalactites (mineral deposits formed from water dripping down from a cave roof) are the most familiar forms of speleothems. Speleothems are mineral deposits formed from groundwater within underground caverns.

• The Nat Geo News article says the structures have been noticed by all visitors to the Bruniquel cave, “from the first speleologists” onward. What are speleologists?
  • Speleologists are people who study caves, including their geological formation, ecology, and uses.

• How do scientists think the stalagmite structures were built?
  • More than 400 stalagmites were cut and worn down to roughly the same length.
  • The stalagmites were arranged in two annular formations, the larger about 6.7 meters (22 feet) in diameter. (Annular simply means ring-shaped.)
  • Other stalagmites were stacked in heaps inside and outside the annular structures.

• What kind of organization or organizational thinking is implied by the Bruniquel cave structures?
  • To craft those enormous stone rings, researchers say the cave’s occupants needed a reliable source of illumination, some kind of social organization, and the ability to conceive of and construct the patterns.
    • “This requires the mobilization of people who choose, who lead, who advise, manufacture—and with continuous light,” says lead researcher Jacques Jaubert. “All this indicates a structured society.”
    • This is a radically different (and much more advanced) social organization than anthropologists have previously associated with Neanderthals.

• Why do scientists think the Bruniquel cave structures were made by Neanderthals?
  • Dissent: Well, not all scientists do think the structures are man-made. At least one paleoanthropologist thinks the structures could have been accidentally created by hibernating cave bears. “Who in their right minds builds structures 300 meters underground inside of a cave? … When bears settle in for the winter hibernation, they push all kinds of litter to the side. This looks like a place where cave bears settled in for a nice nap over and over through time.”
  • Age: The structures are old. Scientists conducted radioactive dating on the stalagmites, and found they are about 176,500 years old. Early modern humans (Homo sapiens) arrived in Europe only about 40,000 years ago. The spatial organization at Bruniquel Cave is the first one attributed with certitude to the early Middle Palaeolithic.
  • Construction: The annular shape of the structures indicate they were made on purpose—the heaps of stalagmites are deliberately arranged. The cave also has evidence of fire and charred bits of bone, often telltale signs of Neanderthal habitation.
    • Study authors say the construction of the circles indicates they were not made by cave bears: “[B]ear dens are generally smaller than the largest ring … and the animals don’t stack stalagmites so much as excavate hollows and brush things aside. Plus, Jaubert notes, ‘bears do not make fire.’”

TEACHERS’ TOOLKIT

Nat Geo: Neanderthals Built Mysterious Stone Circles

Nat Geo: Why We Explore activity

(extra credit!) Nature: Early Neanderthal constructions deep in Bruniquel Cave in southwestern France