Footprints provide clues to how humans stalked and hunted giant sloths

Among the glistening dunes of New Mexico's White Sands National Monument, scientists have been taken aback by the discovery of footprints.

The footprints belong to the extinct giant ground sloth, measuring seven to eight feet tall when on its hind legs, and sporting razor-like claws — vastly different to the lazy looking sloths you're familiar with today.

But it's what's inside these sloth footprints that's captivated researchers: human footprints. This suggests hunters were possibly following the ground sloth step-for-step, despite the animal's ability to strike and kill.

The discovery has been published in Science Advances, where a team led by Bournemouth University's Matthew Bennett are trying to understand the interaction between sloths and humans thousands of years ago.

What's also interested researchers is the appearance of other human footprints at the site, but at a safe distance from the sloth's. These hunters possibly used diversion to gain an advantage over the animal.

"Understanding the way in which our ancestors might have tackled big prey, and the fact that they tackled big prey is quite interesting, because a big animal like this would’ve come with huge amounts of risk," Bennett said in a video statement.

"If you were chasing a small rabbit or something, [there is] little risk associated, but going head-to-head with a sloth, the chances are you might come off badly. Therefore, what justifies that greater risk?"

Bennett added that the tracks show the sloth turning and swinging at the stalker, with another hunter coming in to hit and kill the animal.

"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," he added in a statement online.

"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."

The findings will give researchers a better understanding of how humans hunted large animals, and whether they played a role in the sloth's extinction.

But first, researchers will need to figure out when this man versus sloth battle took place, which is likely before the Ice Age at least 11,700 years ago, given ground sloths were already extinct by that time.