Paleontologists in southwestern North Dakota have unearthed four massive, 66.5-million-year-old fossilized footprints representing the first adult Tyrannosaurus rex trackway ever discovered. A high-school teacher and amateur fossil hunter spotted the trail during a 2025 field dig, and researchers published the findings in the Journal of Vertebrate Paleontology on September 8, 2026.
While isolated dinosaur bones and scattered adult prints have surfaced across the American West over decades of fieldwork, scientists have long missed a continuous record of how the Hell Creek Formation’s apex predator moved across its ancient ecosystem. That changed when Kent Hups, a teacher at Northglenn High School and amateur fossil hunter based in Northglenn, Colorado, volunteered on a paleontology dig led by the Denver Museum of Nature & Science just outside of Marmarth, North Dakota.
As a teacher, I’m always telling my students that science starts with curiosity, passion and careful observation. I never imagined that could lead me to a discovery like this,
Hups said in a statement.
Spotting the Tracks Near Marmarth and the Hell Creek Geology
Hups initially noticed a strange protrusion sticking out of the ground on federal land administered by the U.S. Forest Service. When he examined the lumpy, wedge-shaped formation, he recognized three splayed toes. Though initial skepticism greeted his announcement because only two adult T. rex tracks had ever been uncovered—one in New Mexico and another in Montana—the team returned the following day to find a full sequence.
The resulting 23-foot-long trackway consists of four large, three-toed prints, featuring two left and two right footprints. Each print measures roughly 3 feet in length, with a stride of approximately 13 feet. Researchers estimate the dinosaur walked at a speed of 3.4 to 4.5 miles per hour, a pace comparable to a brisk human walk. One print even retains a clear claw impression.
The surrounding rock layers present a unique geological puzzle. Famous skeletons like Sue, Teen-rex
discovered by three children in 2022, Gus which sold for a record $50.1 million, and Stan which sold for $31.8 million in 2020 all emerged from these same regional strata. Yet large theropod trackways remain exceptionally scarce because the ancient environment was a braided stream floodplain where soft mud footprints typically eroded away.
How Bacterial Preservation Turned Mud Depressions Into Stone Casts
The survival of the trackway relies on a rare sequence of natural preservation. Scientists hypothesize that after the heavy predator marched through the swampy landscape, water laden with bacteria flooded the footprint depressions. This microbial activity created chemical conditions where dissolved minerals accumulated layer by layer.
Calcium carbonate and sandstone cemented the sediment into a dense mass significantly harder than the surrounding mud. Over millions of years, erosion stripped away the softer matrix, leaving the hardened prints exposed as raised, three-dimensional casts rather than hollow molds. Because of this weathering, the speed estimate is approximate.
High-Resolution 3D Scanning and Digital Reconstruction
To document the fragile site before erosion claims it, researchers deployed advanced digital documentation tools in the field. The team performed high-resolution 3D surface scanning on each footprint and the entire trackway, generating digital models for detailed study.
/https://tf-cmsv2-smithsonianmag-media.s3.amazonaws.com/filer_public/1a/a6/1aa67fc3-b755-4ed5-b9eb-5e3f801ad982/walkingtrexillustration_credit_andrey_atuchin.jpg "Photo: Smithsonian Magazine")
Peter Falkingham, a professor of paleobiology at Liverpool John Moores University and lead author of the study published on September 8, 2026, analyzed the data remotely.
The technology we’re able to apply in the digital age means my colleagues could scan the tracks in the field and then send the 3D information over to me to visualize on my computer and in VR, enabling me to take as close a look as they did in person.
Peter Falkingham, Liverpool John Moores University
Museum Recovery Plans and What the Trackway Reveals
Bones offer extensive anatomical data, but paleontologists emphasize that trackways capture dynamic movement across an ancient landscape. Dr. Tyler Lyson, senior curator of vertebrate paleontology at the Denver Museum of Nature & Science, noted the rarity of the find.
Bones tell us an enormous amount about these animals, but footprints capture a moment of behavior. With a trackway, we can actually follow an animal as it moved across the landscape. That is incredibly rare for T. rex.
Dr. Tyler Lyson, Denver Museum of Nature & Science
To protect the specimens from weathering and erosion, three of the footprints are scheduled for helicopter extraction. They will be transported to the Denver Museum of Nature & Science, which plans to share recovery updates with visitors during the winter months.
