A 66.5-million-year-old set of four three-toed footprints, known as a trackway, has been identified as likely made by an adult Tyrannosaurus rex, one of the largest predators of the Late Cretaceous period. The discovery was made in the Hell Creek Formation, located in southwestern North Dakota, and marks the first documented trackway of an adult T. rex. The trackway, which is about 23 feet (7 meters) long, was found on federal land managed by the U.S. Forest Service near the town of Marmarth. Each footprint is approximately 3 feet (0.9 meters) long, and the researchers used high-resolution 3D surface scanning to capture detailed images of the prints. The findings have been published in the Journal of Vertebrate Paleontology, a respected scientific journal that focuses on the study of fossil vertebrates. Scientists estimate that the T. rex was walking at a speed of about 3.5 to 4.5 mph (5.6 to 7.2 km/h), similar to a human walking briskly. This estimate is based on the length of the trackway’s stride, which was approximately 13 feet (4 meters). The trackway was discovered in 2025 and is expected to be partially recovered by helicopter this fall. Three of the footprints will be transported to the Denver Museum of Nature & Science for further study and display. The museum plans to provide updates on the recovery process during the winter months. The research team includes scientists from the Denver Museum of Nature & Science and Liverpool John Moores University in England. Peter Falkingham, a professor of paleobiology at Liverpool John Moores University, was the lead author of the study, even though he did not visit the site in person. Instead, he used 3D scanning technology to analyze the footprints remotely. Kent M. Hups, a high school teacher from Northglenn, Colorado, who discovered the site, co-authored the paper. The study was led by Tyler Lyson, a senior curator of vertebrate paleontology at the Denver Museum of Nature & Science, with Evan Tamez-Galvan responsible for conducting the surface scanning. This discovery offers new insights into the movement and behavior of T. rex, one of the most iconic dinosaurs in the fossil record. By studying trackways, scientists can infer details about a dinosaur’s speed, gait, and even potential social behavior. The use of modern technology, such as 3D scanning, allows researchers to analyze these ancient footprints with greater precision, even when they cannot visit the site in person. The collaboration between educators, museum scientists, and university researchers highlights the growing role of interdisciplinary efforts in paleontology.