For over a century, the apex predator of the Cretaceous period has been understood almost exclusively through its osteological remains. Paleontologists have painstakingly reassembled jawbones, massive femurs, and teeth to reconstruct the terrifying physical presence of Tyrannosaurus rex. Yet, bones can only tell us how an animal was built; they reveal very little about how it actually moved across a living landscape.
In a milestone paper published in the Journal of Vertebrate Paleontology, an international research team led by scientists from the Denver Museum of Nature and Science and Liverpool John Moores University announced a monumental paleontological breakthrough: the discovery of the first verified trackway left by a fully grown adult Tyrannosaurus rex. Preserved in the badlands of southwestern North Dakota near the town of Marmarth, the 23-foot-long trail preserves four distinct, three-toed footprints left in wet sediment approximately 66.5 million years ago, offering an unprecedented real-time snapshot of the legendary predator taking a casual walk.
The findings were reported by Taylor and Francis Group and ScienceAlert.
The Footpath of a Titan
While isolated T. rex prints have been documented in New Mexico and Montana over the decades, isolated impressions are limited. Without a sequential trackway, it is mathematically impossible to calculate an animal's gait, balance, or active speed. The site was initially spotted in 2025 on U.S. Forest Service land by Kent M. Hups, a high school science teacher from Northglenn High School who was volunteering on a field expedition. The alternating sequence features two left and two right footprints pressed deep into the ancient mud of the famous Hell Creek Formation.
Each footprint measures roughly 3 feet long, featuring the narrow, tridactyl (three-toed) design characteristic of massive theropods. Given the sheer scale of the prints, the narrow angle of the toes, and the overwhelming abundance of T. rex skeletal fossils in the surrounding Hell Creek stratum, researchers concluded that an adult Tyrannosaurus rex was the only viable candidate. The trackway metrics reveal a stride length of approximately 13.1 feet, with the animal moving at an estimated velocity of 3.5 to 4.5 miles per hour.
This discovery builds on the rich fossil record of the Hell Creek Formation, which has yielded countless insights into the final chapter of the dinosaur age, including the recent coprolite feather discovery that revealed a three-tiered Cretaceous food web. Together, these finds are painting an increasingly detailed picture of life in the moments before the K-Pg mass extinction.
Walking, Not Running | Calculating the Pace
One of the most revealing insights provided by the trackway is the calculated velocity of the animal. By analyzing the 13-foot stride length in relation to estimated hip height, co-author Dr. Peter Falkingham applied advanced 3D photogrammetry and biomechanical modeling to determine the dinosaur's pace. Contrary to cinematic portrayals of T. rex constantly sprinting down prey, the trackway captures a calm, energy-efficient stroll.
Moving at roughly 3.5 to 4.5 miles per hour, the multi-ton predator was moving at a speed comparable to a person walking briskly down the street, demonstrating how large theropods managed their immense body mass during daily transit. The gait analysis reveals balanced weight distribution across heavy footpads with minimal rotational stress, suggesting the animal was conserving energy while traversing coastal floodplains. This biomechanical insight challenges popular depictions of T. rex as a constant sprinter and supports the growing scientific consensus that the apex predator was an ambush hunter that relied on short bursts of speed rather than sustained pursuit.
The application of 3D photogrammetry and biomechanical modeling to fossil trackways mirrors the advanced imaging techniques used in other fields of paleontology, from the virtual unwrapping of Herculaneum scrolls to the micro-CT analysis of fossilized coprolites.
VR Technology Meets Helicopter Excavation
Because the footprints were carved into weathered gumbo clay atop a steep, eroding butte, the research team relied heavily on modern digital preservation. Using high-resolution LiDAR and 3D surface scanning in the field, researchers transmitted volumetric spatial data directly to laboratory systems. This allowed team members across the globe to inspect the precise depth, rim displacement, and sediment compression of the prints in virtual reality.
To shield the fragile tracks from harsh North Dakota winters, a specialized field team is preparing to extract three of the heavy stone footprints via heavy-lift helicopter. The slabs will be transported to the Denver Museum of Nature and Science for permanent stabilization, laboratory study, and public display. The combination of VR preservation and physical extraction represents a new gold standard for paleontological fieldwork, ensuring that even if the original site erodes away, the scientific data will survive indefinitely.
This intersection of cutting-edge technology and fossil discovery parallels the innovative approaches seen across the natural sciences, from evolutionary biology to marine conservation, where new tools are revealing details that were previously invisible to science.
Frequently Asked Questions
As the research team noted in their study: "A trackway is a fossilized action, preserving a specific minute of a specific day 66.5 million years ago." Looking down at a three-foot impression in the stone allows us to step out of speculative theory and stand directly beside a living, breathing creature as it navigated its ancient world.