Paleontologists have uncovered four massive three-toed footprints in southwestern North Dakota that researchers describe as the first known adult Tyrannosaurus rex trackway. Discovered in 2025 by a high school science teacher volunteering on a dig, the 23-foot trail dates back roughly 66.5 million years.
Kent Hups and the Discovery in the Hell Creek Formation
While volunteering on a paleontological excavation led by the Denver Museum of Nature & Science just outside Marmarth, North Dakota, amateur fossil hunter and high school teacher Kent Hups spotted a strange, lumpy protrusion sticking out of the ground in 2025. Working on federal land administered by the U.S. Forest Service, Hups initially suspected he had found a dinosaur footprint, though Tyler Lyson, senior curator of vertebrate paleontology at the museum, remained skeptical at first.
Only two isolated adult Tyrannosaurus rex tracks had ever been uncovered previously—one in New Mexico and another in Montana. When the team returned to the North Dakota site the following day, however, they uncovered a continuous 23-foot-long trackway featuring two left and two right footprints. The find was detailed in research published September 8 in the Journal of Vertebrate Paleontology. The surrounding geologic layer, known as the Hell Creek Formation, spans eastern Montana, the Dakotas, and Wyoming, and has previously yielded famous specimens such as Sue, the juvenile Teen Rex
discovered by three children in 2022, and record-breaking fossils like Gus and Stan.
Kent Hups said that as a teacher, he was always telling his students that science starts with curiosity, passion, and careful observation, according to Smithsonianmag and Goodnewsnetwork.
Walking Pace and Behavioral Insights From Fossilized Tracks
Each footprint in the North Dakota trackway stretches approximately three feet long and exhibits the narrow, three-toed shape characteristic of large theropods. Based on the stride lengths—measured at roughly 13 feet—and foot dimensions, researchers estimate the dinosaur was moving at a speed of about 3.4 to 4.5 miles per hour, or approximately 1.6 meters per second. Because the tracks are heavily weathered, these speed calculations remain approximate.
Rather than capturing a predatory sprint, the footprints document an everyday, unhurried walk. This pace is roughly comparable to a brisk human walking pace across town, offering a rare glimpse into the energy-efficient daily movements of a mature predator. While skeletal remains establish anatomy, trackways capture specific moments of behavior across an ancient landscape.
Tyler Lyson said that bones tell us an enormous amount about these animals, but footprints capture a moment of behavior, adding that with a trackway, we can actually follow an animal as it moved across the terrain, which is incredibly rare for T. rex, according to Goodnewsnetwork.
How 66-Million-Year-Old Footprints Survived Erosion
Finding large theropod trackways in the Hell Creek Formation is exceptionally unusual. Millions of years ago, the region served as a riparian habitat characterized by floodplains braided with streams, meaning soft mud impressions typically eroded away quickly.
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Scientists hypothesize that a unique combination of environmental factors preserved the trail. Bacteria-laden water likely flooded the footprint depressions, creating chemical conditions that allowed dissolved minerals to accumulate layer by layer. Over millions of years, erosion wore away the softer material, leaving the tracks exposed today as raised, three-dimensional casts rather than hollow molds.
Digital Mapping and Planned Museum Recovery
To document the find before natural weathering destroys the exposed site, researchers deployed high-resolution 3D surface scanning in the field. Peter Falkingham, a professor of paleobiology at Liverpool John Moores University and lead author of the study, utilized the digital models to analyze the specimens remotely.
To prevent the fossils from being lost to ongoing erosion, museum teams plan to recover three of the footprints by helicopter. The specimens will be transported to the Denver Museum of Nature & Science for detailed study, with public updates scheduled throughout the winter.