Scientists Identify First Adult Tyrannosaurus Rex Trackway in North Dakota

Researchers from the Denver Museum of Nature & Science and Liverpool John Moores University have documented the first trackway attributed to an adult Tyrannosaurus rex. The four three-toed footprints, found on U.S. Forest Service land near Marmarth, North Dakota, span roughly 23 feet and date to about 66.5 million years ago, shortly before the mass extinction event.

Each print measures about three feet in length, with a stride of approximately 13 feet between successive footprints of the same foot. Applying standard locomotion equations to the size and spacing of the prints suggests the animal moved at roughly 3.5 to 4.5 miles per hour, comparable to a brisk human walk.

The identification relies on the prints' size, the narrow angle between toe impressions, and the presence of adult T. rex fossils in the same formation, which together rule out smaller theropods or juvenile specimens. Earlier trackways in Canada and Wyoming were linked to juveniles or related species, but this sequence provides a clear stride pattern for an adult.

The footprints were recorded using high-resolution 3D scanning, allowing lead author Peter Falkingham to analyze the trackway remotely. The discovery was initially made by a high-school teacher participating in the museum’s field program. Three of the four prints are scheduled to be airlifted and displayed at the Denver Museum.

"With a trackway, we can actually follow an animal as it moved across the landscape," said Tyler Lyson, senior curator at the Denver Museum.

The find offers direct evidence of T. rex locomotion, supporting biomechanical models that propose the apex predator favored a steady, efficient gait rather than high speeds. While the data point is singular, it provides a tangible reference for how a fully grown T. rex may have moved in its final millions of years.