Paleontologists have discovered the first known adult Tyrannosaurus rex trackway in southwestern North Dakota’s Hell Creek Formation. Dating back 66.5 million years, the 23-foot-long series of four footprints offers rare behavioral insights into how the giant carnivore moved across the ancient landscape just before the end of the Cretaceous period.
Scientists studying the apex predator of the Late Cretaceous have relied almost entirely on skeletal remains to understand its biology. Now, a rare set of four connected footprints found in the badlands of southwestern North Dakota near the Montana border provides physical evidence of an adult Tyrannosaurus rex in motion, offering a glimpse into real-time dinosaur behavior shortly before an asteroid impact wiped out the species.
Discovery in the Hell Creek Formation
The 23-foot-long trackway was identified by researchers from the Denver Museum of Nature and Science and Liverpool John Moores University in the UK. The site sits within the fossil-rich Hell Creek Formation, a geological division spanning parts of North America that has long yielded dinosaur remains.
According to CBS News, the discovery on U.S. Forest Service land near Marmarth was made by Kent Hups, a high school teacher and amateur fossil hunter volunteering on a dig led by museum curator Dr. Tyler Lyson. FOX Weather notes that the site is located specifically on the Dakota Prairie Grasslands in Slope County.
“As a teacher, I’m always telling my students that science starts with curiosity, passion and careful observation,” said Kent Hups, who is a longtime museum volunteer and also co-authored the paper. “I never imagined that could lead me to a discovery like this.”
Kent Hups, high school teacher and museum volunteer, via CBS News
Tracking an Adult Predator Across the Ancient Landscape
Before this find, only two isolated adult T. rex footprints had been confirmed globally—one in New Mexico and one in Montana—neither of which preserved a continuous walking sequence. The North Dakota discovery comprises four distinct, three-toed impressions left by a fully grown animal.
“Bones tell us an enormous amount about these animals, but footprints capture a moment of behavior,” said Tyler Lyson, senior curator of vertebrate paleontology at the Denver museum. “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 at the Denver museum, via CBS News
Each footprint measures approximately 3 feet long. By analyzing the spacing between the impressions, researchers calculated that the dinosaur maintained a stride of about 13 feet. Based on these measurements, scientists estimate the animal moved at a pace of roughly 3.5 to 4.5 mph—comparable to a brisk human walking speed, despite the creature weighing more than seven tons.
Digital Mapping and Geological Context in North Dakota
To analyze the find without disturbing the site immediately, researchers deployed high-resolution 3D surface scanning equipment in the field. Peter Falkingham, a professor of paleobiology at Liverpool John Moores University and lead author of the study published in the Journal of Vertebrate Paleontology, examined 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.”
Photo: CBS News
Peter Falkingham, professor of paleobiology at Liverpool John Moores University, via FOX Weather
Geologically, the tracks are preserved within fine-grained sandstone concretions cemented by calcium carbonate, which formed and hardened directly around the depressions left by the dinosaur’s feet. Paleontologists linked the tracks specifically to Tyrannosaurus rex based on their massive size, anatomical shape, and the high concentration of tyrannosaur skeletal elements recovered from the same local strata. These include a juvenile specimen known as “Teen Rex,” found in the same badlands in 2022 by three boys on a family hike.
The prehistoric walk dates back approximately 66.5 million years, placing it near the absolute conclusion of the Cretaceous period. Following the initial field documentation and digital modeling, museum plans dictate that three of the four discovered footprints will be recovered by helicopter and transported to the Denver Museum of Nature and Science for further study.
