GHOST TRACKS OF WHITE SANDS

Scientists are uncovering fossilized footprints in the New Mexico desert that show how humans and Ice Age animals shared the landscape

- KAREN COATES

The sun shines nearly 300 days a year over southern New Mexico’s Tularosa Basin, where bright white sand ripples across the desert. Here, in White Sands National Park, the world’s largest gypsum dunes abut the dried-up bed of prehistoric Lake Otero, which once covered 1,600 square miles. In the summer, park temperatures can reach 110°F. One’s eyes sting in the intense sunlight. It was just such a sunny day in May 2021 when Bonnie Leno and Kim Charlie, sisters from Acoma Pueblo, about 175 miles north, found the fossilized tracks of a giant ground sloth and two humans, all of whom lived at least 10,000 years ago, at the close of the Pleistocene Epoch.

Leno and Charlie didn’t expect to uncover a piece of late Pleistocene history at the park, but there they were, the kidney-shaped footprints of a 10-foot-tall, 2,000-pound long-extinct mammal and the imprints of human toes—evidence of two species that coexisted thousands of years ago. “I was down on the ground, brushing everything off,” says Leno, recalling the adult human footprint she found not far below the surface. “I was ecstatic.” Just inches away, she spotted the giant sloth track. “There were a lot of prints in that area,” says Charlie, who uncovered the tiny footprint of a child nearby.