Footprints Preserve Giant Sloth's Last Stand

Early humans attempt to hunt and distract a giant ground sloth in this artist's illustration. Alex McClelland/Bournemouth University

More than 10,000 years ago, a group of early humans stalked a giant ground sloth along the shores of what was then a muddy lake. At some point, someone or something spooked the now-extinct creature, it reared up on its hind legs and the fight began in earnest.

And now we have an ending to a story lost to the flow of time.

A study published in Science Advances outlines such an encounter based on preserved footprints found in White Sands National Monument in New Mexico. The scene is evidence of early humans stalking, hunting and perhaps even killing a giant ground sloth.

How do we know the humans were stalking this creature? Their footprints were inside the sloth's footprint, which is indicative of tracking.

A hunt frozen in time

Going after a giant ground sloth wouldn't have been an easy task. These creatures aren't anything like the sloths we know today. Instead, imagine a hairy beast weighing 1 ton, measuring almost 10 feet long and equipped with long, wolverine-like claws. It was basically the size of a modern-day elephant, and it could also operate on its hind legs.

Yet early humans clearly hunted the creatures, and evidence from the site in New Mexico demonstrates that they worked together in an effort to bring down the massive prey.

"So we ask why? Adolescent exuberance? Possible but unlikely," Matthew Bennett, a professor of environmental and geographical sciences at Bournemouth University in England and one of the researchers involved in the study, said in a National Parks Services statement.

"We see interesting circles of sloth tracks in these stalked trackways which we call 'flailing circles.' These record the rise of the sloth on its hind legs and the swing of its fore legs presumably in a defensive motion."

A preserved giant ground sloth footprint with a human footprint in it
The human stalking this giant ground sloth made sure to step in the sloth's footprints. Science Advances

In addition to the footprints within the footprints, researchers found a collection of human footprints a safe distance away, indicating that a group of humans were involved in the hunt, possibly working to distract the creature while the hunter attempted to wound it with a stone-head spear.

"We also see human tracks on tip toes approach these circles; was this someone approaching with stealth to deliver a killer blow while the sloth was being distracted? We believe so," Bennett said. "It was also a family affair as we see lots of evidence of children's tracks and assembled crowds along the edge of the flat playa.

"Piecing the puzzle we can see how sloth were kept on the flat playa by a horde of people and distracted by a hunter stalking the sloth from behind, while another crept forward and tried to strike the killing blow as the animal turned."

While researchers can't know the results of this particular hunt, the tracks lend credence to a theory that these early humans contributed to the decline of the giant creatures, along with disease and a changing climate.

If you're hoping to get a look at these tracks the next time you visit White Sands, you're out of luck. The area where the tracks were discovered is in the badlands, an area not open to the public for safety reasons. That doesn't mean visitors won't be able to see or experience the find, however. The study's documentation may be used in some capacity to educate members of the public about the discovery.

"We will benefit from their work by using all of this to develop interpretive materials that people can see, touch and experience at the park visitor center or online at National Park Service web sites," White Sands Superintendent Marie Sauter said.