This is a slightly edited version of an article I wrote for New Scientist.

The caves of Northern Iberia were once home to some of our earliest human ancestors. Where once we found shelter, now we uncover artefacts of our past such as recent evidence for early humans hunting behaviour.

Situated in Cantabria, Spain, the La Garma cave is a hotbed of Upper Palaeolithic finds, containing everything from human burial sites and spear tips to engraved horse bones and cave paintings. Sealed by a rockslide for 16,000 years, La Garma lies preserved, a snapshot of Paleolithic life.

Such snapshots produce fragile working environments, as lead author Marián Cueto, of Universidad de Cantabria, explained “we can’t walk freely at the site, instead moving over metallic platforms to avoid disturbing the original floor. This process is tedious and slow but it is the best way to preserve the original disposition.”

During the latest expedition, Marián’s team discovered a collection of toe bones believed to have belonged to a single cave lion. Closely related and similar in size to modern lions, cave lions once roamed across wide areas of Europe, Asia and North America, before becoming extinct 14,000 years ago as the glaciers receded.

Subtle markings, similar to those produced when a modern hunter skins a lion with the intention of keeping the claws and furs attached, are present on each bone. These therefore represent evidence for a skilled Palaeolithic worker with both a specific intention and previous experience.

Being found near what remains of three stone huts, within the cave’s lower gallery, Marian and her team suspect that the pelt may once have covered one of the dwellings. Similar findings previously found in Swabian Jura, Germany, further suggest that human hunting of cave lions was a widespread, if infrequent, event.

On why this hunting occurred, Marian states that “it was a risky and dangerous task, but is not possible to know if this was a collective activity or an individual action with social and ritual connotations”.

Further analysis is underway to determine if other carnivore fossils in La Garma, including those of hyenas, foxes and bears, were skinned in a similar fashion.

Even after more than ten years of work, Cueto and her team know that vast areas of the cave remain to be explored with each new expedition shedding new light on our hidden past.