First known T. rex trackway reveals how the dinosaur moved

Kent Hups set out one morning on a research expedition in the famed Hell Creek Formation, a series of fossil-rich sedimentary rock layers in the western United States. The vast formation, spanning parts of Montana, Wyoming, North Dakota and South Dakota, is abundant in Late Cretaceous dinosaur bones — but finding footprints is a different story. The area’s sediments typically eroded before the tracks could be preserved. Yet Hups, a high school science teacher from Northglenn, Colorado, found himself looking down at what ended up being the first known trackway left behind by a T. rex. “My first reaction was total disbelief,” said Hups, a volunteer research associate at the Denver Museum of Nature & Science.