NATURE NOTES:
In the “Ghost Prints” of White Sands, Stories of Ice-Age Animals, and the Continent’s First People

By Andrew Stuart

In December 2019, a Chihuahuan Desert place became the country’s newest national park, White Sands, in New Mexico, preserves a vast, shining dunefield. But like every national park, its wonders are manifold.

In recent years, researchers here have found thousands of fossilized Ice Age footprints – of vanished animals, and of humans. It’s an unparalleled record, and it speaks as powerfully as any artifact could to the life of the continent’s earliest people. 

“The story sort of begins with Bigfoot,” David Bustos, the park’s chief of resources, said.

In 1932, a government trapper named Ellis Wright returned from an outing here with a Sasquatch story. He said he’d found footprints – 22 inches long, and 8 inches wide. An expedition to find the prints failed – and Wright became an object of mockery.

Seventy-five years later, his tale took on a different meaning.

“We’ve been finding giant ground sloth footprints,” Bustos said, “and the footprints of giant ground sloths are about 22 inches long and about 8 inches across. So he did find a ‘big foot,’ but maybe not a Sasquatch.”

The recognition began in 2006. On the park’s west side, on the margins of a dry lakebed, Bustos found prints he knew to be ancient. Interns and others helped document the tracks. Park staff now believe there are tens if not hundreds of thousands of footprints.

They represent a range of Ice Age “megafauna,” animals that vanished some 10,000 years ago. Certain prints are ubiquitous.

“We see giant ground sloths, camels, mammoths and humans,” Bustos said. “That happens over and over and over again in these different areas.”

The most compelling prints capture the interaction of humans with these animals. One set records a confrontation – and a cooperative hunt.

“You can see the prints where they come running up to a giant ground sloth,” Bustos said, “and the giant ground sloth stands up and spins around, and there are these marks on the ground. And from another direction, a person is running up behind the sloth, and stepping backward and forwards. You can see all these interesting motions – coming up on the balls of your toes like you’re going to throw something.”

Nearby are other prints, including those of children, who were lifted, carried and put down again. Fellow community members apparently looked on, as hunters did their work on the elephant-sized sloth.

Judging by other trackways in the park, sloths knew the score.

“Over and over,” Bustos said, “when humans are anywhere near that area, the sloths will immediately turn around and go the other direction.”

Then, there are signs of play. In one, a person followed a sloth’s tracks, and elongated their stride to step in the prints. In another, puddles formed where a sloth had passed.

“Then you’ll see children’s prints,” Bustos said, “and it looks like the children were jumping inside puddles that were made by giant ground sloths. I guess children will always enjoy jumping in puddles.”

Some prints were laid in clay, at the upper edges of an Ice Age lake. In others, footprints fossilized into a hard stone called dolomite – and stand like pedestals. But many are “ghost prints” – only visible with moisture. Perhaps Wright’s “Bigfoot” was such a print.

The research is just beginning – even as the tracks themselves are vanishing. Erosion of the layer in which they’re found seems to be accelerating, perhaps due to increasing drought.

There are questions about the Ice Age past – what humans hunted, whether they contributed to megafauna extinctions – that these prints could help answer. 

Bustos said seeing them disappear is like watching a library burn.

“There’s a lot of really incredible stories to be unlocked in these prints, that might help to tell some of these important stories,” he said. “But it’s sort of like that section of the library is on fire, it’s rapidly burning up – so we’re trying to get out there and gather as much information as we can, because some of these trackways will be gone in six months to a year. Entire trackways will be lost.”

White Sands’ new national-park status could mean more support for that work. The area where the footprints are found contains unexploded ordnance from the adjacent White Sands Missile Range, and is closed to visitors. But in the future there could be volunteer opportunities in documenting these prints – which are baffling as traces of a vanished world, and instantly recognizable in their humanity.