Qualla: Sidron Cave

Sidron Cave: Introduction

Fri, 13 Mar 2026 00:00:00 GMT

Photo credit Xuliu Pombar, CC0. In 1994, someone stumbled on human bones in a cave in the Pilona municipality of Asturias and assumed the worst. Republican fighters had hidden in these limestone passages during the Spanish Civil War, and the remains seemed like another grim discovery from that conflict. But the bones were not fifty years old. They were roughly 49,000 years old, belonging to Neanderthals who had lived and died in these mountains tens of thousands of years before the first modern humans reached the Iberian Peninsula. What began as a suspected war grave became one of the most important Neanderthal sites in the world.

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Image: Xuliu Pombar | CC0

Sidron Cave: The Tunnel of Bones

Fri, 13 Mar 2026 00:00:00 GMT

Photo credit Xuliu Pombar, CC0. El Sidron is enormous -- 3,700 meters of non-carboniferous limestone karst passages, including a central hall stretching 200 meters. But the discovery that made the cave famous occupies a far smaller space: the Galeria del Osario, the Ossuary Gallery, just 28 meters long and 12 m...

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Image: Xuliu Pombar | CC0

Sidron Cave: The Language Gene

Fri, 13 Mar 2026 00:00:00 GMT

Photo credit Xuliu Pombar, CC0. El Sidron transformed what scientists thought they knew about Neanderthals. Among the most startling findings: two individuals from the cave carry the same mutations in the FOXP2 gene -- widely known as the "language gene" -- that are found in modern humans. This does not prove t...

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Image: Xuliu Pombar | CC0

Sidron Cave: A Child Among Them

Fri, 13 Mar 2026 00:00:00 GMT

Photo credit Wikirictor, CC BY-SA 4.0. One of the most poignant finds was El Sidron J1, a juvenile Neanderthal estimated to have been seven or eight years old at death. Roughly 36 percent of the child's skeleton was recovered, including 30 dental elements, a complete mandible, and key cranial and vertebral fragments -...

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Image: Wikirictor | CC BY-SA 4.0

Sidron Cave: A Cave Still Speaking

Fri, 13 Mar 2026 00:00:00 GMT

Photo credit Xuliu Pombar, CC0. Declared a Partial Natural Reserve in 1995, El Sidron serves purposes beyond archaeology. Five species of bats use the cave as a retreat, and two beetle species previously unknown to science were first identified here. The cave's designation protects both its biological residents...

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Image: Xuliu Pombar | CC0