Researchers report the discovery of what appears to be the first known trackway made by an adult Tyrannosaurus rex near Marmarth, North Dakota. The 23-foot series contains four three-toed prints, each about 3 feet long, preserved in the Hell Creek Formation and dated to roughly 66.5 million years ago. Stride length suggests a walking speed of about 3.5–4.5 mph, and three prints are slated to be airlifted to the Denver Museum of Nature & Science for study this fall. High-resolution 3D scans allow researchers to analyze the site remotely while additional buried prints may await future excavation.
Scientists Uncover First Likely Adult T. rex Trackway — Four Giant Prints Found in North Dakota
Image Credit: Eric R. on Unsplash.
A high school science teacher has uncovered what researchers now identify as the first likely trackway made by an adult Tyrannosaurus rex. The impressions were found near Marmarth, North Dakota, in the famous Hell Creek Formation and provide a rare glimpse into how the animal moved more than 66 million years ago.
Discovery and Site Details
Kent Hups, a science teacher at Northglenn High School in Colorado and longtime volunteer with the Denver Museum of Nature & Science, spotted the initial footprint in 2025 while assisting a fossil excavation on federal land managed by the U.S. Forest Service. The preserved series stretches about 23 feet and includes four three-toed prints, each roughly 3 feet long. Sediments containing the prints are dated to about 66.5 million years ago.
Why Researchers Attribute the Prints to T. rex
A team reporting in the Journal of Vertebrate Paleontology concludes that Tyrannosaurus rex is the most probable trackmaker. The attribution is based on the prints' exceptional size, narrow toe impressions, the pattern of left-right tracks, and the abundance of T. rex skeletal fossils previously recovered from the region. While earlier studies have described isolated T. rex tracks in New Mexico and Montana, this is the first reported sequence of footprints likely belonging to an adult individual.
Movement, Preservation, and Study Methods
The four impressions form two left and two right tracks with about 13 feet between successive strides. From that stride length, researchers estimate a walking speed of roughly 3.5 to 4.5 mph — comparable to a brisk human walk. Because the prints are heavily weathered, the speed is an estimate, but the presence of multiple consecutive prints offers an unusually informative window into adult T. rex locomotion.
The research team used high-resolution 3D scanning to document the entire site, producing detailed digital models that allow remote study and long-term preservation of the impressions without requiring all collaborators to travel to North Dakota.
Recovery and Future Work
Officials expect to helicopter three of the footprints from the site this fall and transport them to the Denver Museum of Nature & Science for careful preparation and further study. The museum plans to share recovery updates with visitors this winter. Researchers also note that additional segments of the trackway may remain buried under the adjacent hillside and could be revealed with further excavation.
Significance: Multiple consecutive adult-sized T. rex footprints are extremely rare. This discovery strengthens understanding of T. rex gait and behavior and complements existing fossil evidence from the Hell Creek Formation.
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