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Kent Hups, a professor from Colorado and amateur fossil hunter, was volunteering at a dig site in North Dakota when he noticed an unusual mark. The discovery revealed four adult T. rex footprints, approximately 1 meter each, preserved in a sequence over 7 meters for 66.5 million years.
A high school teacher volunteering at a paleontological dig in southwestern North Dakota, United States, noticed an unusual formation in the soil of the Hell Creek Formation in 2025. Kent Hups suspected the mark might be a T. rex footprint and triggered the identification of four large tracks preserved in sequence.
According to People on September 15, 2026, researchers concluded that the marks form the first known track likely attributable to an adult Tyrannosaurus rex. The footprints measure approximately 1 meter in length, span about 7 meters, and capture a moment that occurred around 66.5 million years ago.
Professor Noticed a Mark on the Ground During Volunteer Work
Kent Hups is a teacher at Northglenn High School in Colorado and has an amateur interest in fossil hunting. In 2025, he was volunteering at a dig in the Hell Creek Formation in southwestern North Dakota, an area known for preserving remnants from the Late Cretaceous period.
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The team was led by Tyler Lyson, senior curator of vertebrate paleontology at the Denver Museum of Nature & Science and a friend of Hups. During the work, the professor noticed a different mark on the ground and raised the possibility that it was a footprint left by a large dinosaur.
However, the initial suspicion did not immediately convince all team members. The team decided to return to the site the next day to examine the formation more closely and verify if there was indeed enough evidence to support that interpretation.
One Possible Footprint Eventually Revealed Four Sequential Marks
When the researchers returned, they realized the discovery was larger than they had imagined. There was not just one isolated mark, but four tridactyl footprints preserved in sequence, forming a true fossilized path.
Each footprint measures approximately 1 meter in length, while the entire set extends over about 7 meters. The arrangement of the marks allowed researchers to study not only the size of the animal but also aspects of its movement.
For the professor, the discovery transformed an apparently simple observation during a volunteer activity into a rare scientific finding. Hups later participated in the academic work on the track as a co-author.
Study Indicates Track Likely Belonged to Adult T. rex
Researchers analyzed the characteristics of the footprints, their dimensions, and the geological context to assess which animal could have produced them. The conclusion presented in the study is cautious: the track is considered likely attributable to an adult Tyrannosaurus rex.
This caution is important because fossilized tracks do not preserve the skeleton of the animal that walked through the area. Identification relies on the combination of shape, size, rock age, known fauna in the region, and comparison with other traces.
The scientific article was published in the Journal of Vertebrate Paleontology on September 8, 2026, with Kent Hups among the authors. Researchers estimated that the footprints were produced approximately 66.5 million years ago, just before the end of the Cretaceous period.
Footprints Allowed for Estimation of How the Animal Walked
The spacing between the four marks provided information that an isolated footprint would have difficulty supplying. The sequence allows for tracking step by step the movement of the animal, creating a sort of frozen record of its behavior.
Based on the dimensions and distance between the footprints, researchers estimated that the animal walked at approximately 3.4 to 4.5 miles per hour, equivalent to about 5.5 to 7.2 km/h.
This indicates a walking pace, not a run. The track literally records some meters traveled by a large theropod tens of millions of years ago, providing a different type of information than what is obtained from fossilized bones alone.
Fossils Preserved a Moment of Behavior for 66.5 Million Years
The footprints were preserved in fine sandstone concretions cemented by calcium carbonate. These structures formed around the depressions left in the soil and ended up being more resistant than some of the surrounding rocks.
Despite this preservation, the molds suffered fractures and other damage over millions of years. Even so, they remained sufficiently recognizable for the professor and his team to reconstruct the sequence of four steps.
For paleontologists, this type of trace has a special characteristic. Bones reveal anatomy, size, and various biological aspects, while footprints can directly record an animal’s movement at a specific moment.
Other T. rex Traces Had Been Found, But Not a Sequence Like This
Isolated footprints previously attributed to adult T. rex have been described in locations such as New Mexico and Montana. The difference with the discovery in North Dakota lies in the sequence, which allows researchers to track several consecutive steps.
According to researchers quoted by People, this is the first time scientists have described a trackway formed by multiple footprints that was likely produced by a mature Tyrannosaurus rex.
This transforms the professor’s finding into an important data point for the study of these animals’ behavior. Instead of merely observing a static mark, scientists can analyze how that individual moved through the landscape at the end of the Cretaceous period.
Professor became a co-author of the study after the observation during excavation
After identifying the first mark and participating in subsequent investigations, Kent Hups transitioned from excavation volunteer to co-author of the scientific paper that formally described the discovery.
The incident also gained special significance because of Hups’s profession. The professor often argues to his students that science relies on curiosity and careful observation, and his own discovery became a practical example of this idea.
The project also brought together dinosaur track specialists and researchers affiliated with the Denver Museum of Nature & Science, who are responsible for deepening the interpretation of the marks and documenting the track scientifically.
Denver museum to preserve and display the rare track
Denver Museum of Nature & Science will be responsible for the track discovered in North Dakota. The institution stated that it is preparing the discovery for public display during the Northern Hemisphere winter.
This piece will allow visitors to observe a sequence that likely records an adult T. rex walking through that region about 66.5 million years ago, preserved until it was noticed by a professor volunteering at the excavation.
The case shows how an apparently unusual mark on the ground can carry an extraordinary amount of scientific information. Four footprints of approximately 1 meter not only suggested which animal passed through the area, but also allowed researchers to estimate its walking pace and track some of its steps through time.
