There was a lot more to Paleolithic life than hunting, gathering, and leaving well-preserved bones for archaeologists. A 14,000-year-old set of footprints and crawl tracks preserves a snapshot of an ancient family’s exploration of a cave in northern Italy—something they apparently did just for the heck of it. The tracks were left in an ancient layer of clay and record how a small group of hunter-gatherers, carrying makeshift torches, waded through ponds and sometimes crawled on their hands and knees to explore the cave. And they apparently brought their young children with them on the adventure.

“Most likely they were pushed into the cave by simple curiosity and a sense of wonder for unexplored places,” archaeologist Marco Romano of the University of Witwatersrand in South Africa, told Ars Technica.

A dangerous idea of family fun

About 180 tracks from the prehistoric explorers remain in the cave floor. Footprints show where they walked; impressions of hands, knees, and the tops of feet show where they crawled through a low tunnel to the cave’s innermost chamber. Based on the size and number of the tracks, at least five people entered the cave, including three children. The youngest child would have been around 3 years old at the time, and their tiny footprints record the small, unsteady steps of a toddler. It’s a rare look at what childhood must have been like for Paleolithic hunter-gatherers.

The size and shape of a print, and its depth at different parts of the foot, can tell you about a person’s size and build, how they moved, and whether or not they were carrying a heavy load. For example, the oldest child’s tracks reveal that they had an unusual gap between their middle toes. It’s impossible to say whether that was an inherited trait or the result of some childhood injury (obviously Paleolithic childhood wasn’t exactly safe), but it doesn’t seem to have slowed the child down at all.

Carrying burning bundles of resinous pine sticks for light, everyone followed close behind the largest adult, with the toddler bringing up the rear. Because the radiometric dates of the footprints cluster so closely together in time, it’s clear that they all explored the cave together. In places, the tracks of the smaller adult lie atop those of the oldest child and the larger adult, but elsewhere, the youngest child stepped right in one of the smaller adult’s prints—so clearly they were there on the same day.

The group stuck close to the side wall of the cave, and dark handprints still mark the walls where the explorers brushed charcoal-smudged hands against the rock. Archaeologists found the burned remains of bundled sticks alongside bits of charcoal on the cave floor, apparently dropped when they were no longer needed. Romano and his colleagues say those bundles would have burned longer than single branches, so these ancient spelunkers clearly knew what they were doing.

It seems they were in pretty good shape, too. “In the case of some knee prints, we were able to recognize using 3D models incredible anatomical details of the leg,” Romano told Ars. “Some really well-preserved impressions show the muscle structure of the knee joint and adjacent regions.” Based on what they could see of the patella (kneecap), parts of the bones of the lower leg, and the muscles and tendons that connected them, Romano and his colleagues could work out details of the size and build of all five people. They seem to have had the lean, muscular shape you’d expect of active hunter-gatherers.

Isabella Salvador

Marco Avanzini

Emily Packer (Marcomms)

Into the darkness

They followed a sloping 150m (492ft) path into the cave, ascending 12m (40ft) along the way, until they reached the area later explorers dubbed the Corridor of Footprints. A few meters farther along, the tunnel narrowed and lowered to just 80cm (2.6ft). A pair of footprints marks the spot where the group’s leader seems to have paused, rocked back on his heels, and thought it over before deciding to press on.

Single file, the group dropped to their hands and knees and crawled forward into the darkness. Archaeologists have found knee-prints at other sites across Eurasia, marking places where people once knelt, but this is the first set of tracks so far that definitely shows people crawling.

Once they could stand again, the intrepid little group apparently found themselves wading through a small pond, leaving deep prints in the mud at the bottom. At the top of a short slope, they reached the innermost chamber of the cave, which modern explorers call the Sala dei Misteri, 890m (2,919ft) within Mount S. Pietro.

Based on their tracks, the group apparently stayed in the chamber for several minutes, though we’re not entirely sure what happened during that time. Charcoal from their torches still darkens the rock walls, and the adults left charcoal handprints on the 170cm (67 inches) high ceiling. The children seem to have scooped up clay-rich mud from the floor and smeared it on a stalagmite against the far wall, then drew curved, sinuous shapes in the wet clay with their fingers. Today, visitors to the cave can see those fluted finger-tracks, which clearly mark the heights of the three young children.

Although some archaeologists have suggested that this might have been part of a ritual of some sort, there’s no way to be sure of that—and it’s important to remember that not everything ancient people did was ritual or ceremonial, any more than all of our random daily activities are today. It’s entirely possible that the decorated stalagmite may just be evidence of the kids playing for a few minutes while the adults looked around.

At last, they left. This time, they followed an upper corridor, with a higher ceiling and a drier floor. Shortly after they made it out, according to radiocarbon dating, a stalactite fell, blocking the Corridor of Footprints with heavy rock and sealing away the muddy record of the family’s outing. People kept using the outermost chamber—archaeologists have found artifacts from the late Roman period—but the inner reaches remained inaccessible.

“So from that moment no humans could enter the cave, until the 1950s when stalactite was blown up with dynamite for the first modern exploration,” Romano said. In the meantime, the mud eventually dried, and cracks now crisscross over some of the footprints. Others lie beneath thin crusts of carbonate minerals deposited by millennia of dripping water, which allowed radiometric dating of the tracks.

A group of local boys from the nearby town of Toirano made the first post-dynamite venture into Basura Cave in the 1950s, following the same pull of curiosity that had drawn people into the darkness 14,000 years earlier. When word got out about what they’d found, tourists and curious locals flocked to the cave and trampled quite a few tracks in the process. Archaeologists have managed to preserve and study the cave since then, and Romano and his colleagues say it still holds plenty of mysteries.

Currently, the archaeologists are especially interested in the animal prints in the cave, including some canine prints that look, in places, like they’re associated with the human tracks—as if the ancient explorers brought early dogs along with them. It’s going to take more research to confirm whether that’s the case or whether the dogs arrived on their own.

“In addition, we will focus on more archaeological aspects and on the art produced by the explorers in the inner rooms of the cave,” Romano told Ars Technica.

eLife, 2019. DOI: 10.7554/eLife.45204;(About DOIs).