Each year 500,000 people visit New Mexico's White Sands National Monument to hike and frolic among gypsum dunes. This survey revealed the first collection of human tracks: 27 individual footprints that vanished into a dune. “And lo and behold, right where we anticipated they would have been, were human footprints,” he said. Yet National Park Service paleontologists struggled to determine the age of the human prints using geologic techniques like carbon dating. This evidence of an interaction between human and giant sloth is “unique in the world,” Belvedere said.

Source: Washington Post April 25, 2018 18:00 UTC