A series of adult Tyrannosaurus rex footprints, dating back 66.5 million years, has given scientists their first known trackway of an adult T. rex. These tracks offer valuable clues about how the dinosaur moved and behaved. The discovery was made by Kent Hups, a high school science teacher who volunteered on a fossil dig in North Dakota, during an expedition led by Dr. Tyler Lyson, a senior curator at the Denver Museum of Nature & Science. The footprints were found in the Hell Creek Formation, a well-known site for fossil discoveries from the late Cretaceous period. The trackway spans seven meters and includes four distinct footprints. Based on the spacing and size of the prints, scientists estimate that the T. rex was walking at a speed of between 1.5 and 2 meters per second—roughly the pace of a human walking briskly. The site is located about 33 meters below the Cretaceous-Paleogene boundary layer, which marks the time of the massive asteroid impact that led to the extinction of the dinosaurs. This places the tracks just before the catastrophic event that ended the age of dinosaurs. The footprints were preserved through a natural geological process. When the T. rex stepped into soft mud, the depressions were filled with sediment that later hardened into sandstone, creating a cast of the footprints. Each print is about one meter long and was identified as belonging to an adult T. rex based on its size, three-toed shape, narrow toe angles, and the presence of many T. rex skeletons in the surrounding area. Scientists noted that the age of the dinosaur is important in understanding its movement, as younger and older dinosaurs likely moved differently, much like how human toddlers walk differently from adults. Although the surface of the casts is heavily fractured, losing some fine details like skin or pad impressions, the 13-foot stride lengths provided crucial biomechanical data. Researchers are continuing to excavate the site and suspect that a fifth footprint might still be buried beneath the hillside, waiting for natural erosion to reveal it. This ongoing work could provide even more insight into the movement and behavior of one of the most famous dinosaurs in history.