A high school teacher's lucky detour led to the first adult T. rex trackway ever found

Kent Hups was just trying to find an easy way out of a rocky North Dakota valley after a knee replacement when he stopped, stared at a lumpy triangle jutting from the ground, and started to run. The high school science teacher had spent 30 years hunting ancient footprints, and what he was looking at — three splayed, giant-toe shapes on an undisturbed surface — looked like nothing he had ever seen. He yelled. There was nobody to hear it. So he texted his friend Tyler Lyson, a paleontologist digging a few miles away: 'Hey just found a t Rex footprint!!!!!!'

Lyson sent back the same reply he always did: 'Send me a pic.' His skepticism was grounded in a stark fact — at that moment, only two adult T. rex footprints had ever been identified anywhere on Earth, one in New Mexico and one in Montana. A trackway, a sequence of prints from the same animal, was, in his words, 'absolutely improbable.'

That improbable thing turned out to be real. Researchers from the Denver Museum of Nature & Science and Liverpool John Moores University formally described the find on September 8, 2026, in the Journal of Vertebrate Paleontology: the first and only known trackway made by an adult Tyrannosaurus rex, dating to roughly 66.5 million years ago — just before the asteroid impact that ended the age of non-avian dinosaurs.

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.— Tyler Lyson, Senior Curator of Vertebrate Paleontology, Denver Museum of Nature & Science

The trackway sits in the Hell Creek Formation of southwestern North Dakota, on U.S. Forest Service land near the town of Marmarth. It stretches about 7 meters (23 feet) and preserves four three-toed prints — two left, two right — each roughly 1 meter (about 3 feet) long and up to 0.80 meters (2.6 feet) wide. The stride between prints is approximately 4 meters (13 feet). From those measurements, researchers estimate the animal was walking at about 1.5 to 2 meters per second — roughly 3.4 to 4.5 miles per hour, comparable to a brisk human walking pace.

The prints are not hollow molds pressed into soft ground. They are raised, three-dimensional casts — the inverse of what most people picture when they imagine a dinosaur track. The leading hypothesis, according to National Geographic, is that bacteria-laden water flooded the depressions left by the animal's feet, creating conditions for dissolved minerals to accumulate. Layer upon layer of calcium carbonate and sandstone cemented into a mass harder than the surrounding mud. Over millions of years, erosion stripped away the softer material and left the hardened casts exposed, heavily fractured and weathered but unmistakably there.

The team identified T. rex as the most likely trackmaker based on four converging lines of evidence: the exceptional size of the prints, the narrow angle between the toe impressions, the age of the rock layer, and the abundance of T. rex skeletal fossils already recovered from the surrounding area. The Hell Creek Formation has yielded some of the most famous T. rex specimens ever found, including Sue, one of the largest and most complete skeletons on record, and Teen Rex, discovered by three children in 2022.

What makes this discovery stand apart from earlier tyrannosaur track finds is the combination of scale and sequence. Isolated footprints attributed to adult T. rex had been described before — one in New Mexico in 1994 and one in Montana in 2008, according to sci.news. Other tyrannosaur trackways found in Canada and Wyoming were made by smaller animals, either younger individuals or related, smaller species. No one had ever documented a series of steps from a fully grown T. rex — until Hups stumbled into that valley.

The discovery unfolded over two days. On the first, Hups photographed and measured what he could, then climbed to higher ground to get enough cell service to send the images. Lyson remained unconvinced even as the field crew buzzed that evening. The next morning, Hups led companions back to the site. Lyson wanted a pattern — a third print in a predictable location before he would accept the trackway interpretation. He marked a spot in the dirt. A pickaxe struck stone. Footprint three. Then four. Then, eventually, five, extending out of the hillside.

National Geographic reported five footprints visible at the site, while the formal study published in the Journal of Vertebrate Paleontology describes four. The study's four-print count is the figure used in the peer-reviewed analysis.

Peter Falkingham, a professor of palaeobiology at Liverpool John Moores University and the study's lead author, analyzed the tracks without ever visiting North Dakota in person. His team used high-resolution 3D surface scans transmitted digitally from the field, which Falkingham examined on his computer and in virtual reality.

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, Professor of Palaeobiology, Liverpool John Moores University

The digital models serve a preservation purpose as well as a scientific one. The tracks are heavily weathered, and the steep 'gumbo' butte nearby makes further excavation unlikely, the researchers note. Erosion will eventually claim what remains in the field. This summer, the team wrapped three of the four footprints in plaster and burlap in preparation for helicopter transport to the Denver Museum of Nature & Science, where the museum plans to share updates from the recovery with visitors this winter. One footprint even appears to preserve an impression of a T. rex claw, according to Smithsonian Magazine.

The physical tracks, combined with the digital models, may yet reveal more. Researchers say there is a chance the scans could show preserved impressions of the animal's skin. And the trackway itself — a frozen moment of locomotion from 66.5 million years ago — already answers questions that bones alone cannot. It shows an adult T. rex moving at a measured, unhurried pace across what was then a forested floodplain laced with streams, a landscape that also supported the Triceratops whose bones are common in the same area.

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.— Kent Hups, Science Teacher, Northglenn High School and study co-author

Why it matters — A trackway captures something no skeleton can — an animal in motion — and this one is the only record of how the most iconic predator in fossil history actually walked across the Earth.

Sources differ on Number of footprints visible at the site: Five footprints (including one described as 'more ambiguous') (nationalgeographic.com) vs Four footprints (the count used in the formal peer-reviewed study) (eurekalert.org)

Reported by sciencealert.com, sci.news, eurekalert.org, nationalgeographic.com, smithsonianmag.com