First adult Tyrannosaurus rex trackway uncovered in North Dakota badlands

Paleontologists have identified a four-print trackway belonging to a mature Tyrannosaurus rex in the badlands near Marmarth, North Dakota, marking the first known sequence of footprints from an adult specimen. The discovery, reported in the Journal of Vertebrate Paleontology, follows only two previously confirmed isolated adult T. rex prints, found in New Mexico and Montana, which did not reveal locomotion patterns.

The trackway, measuring about 23 feet in length, consists of four three-toed impressions roughly three feet long each. Spacing between the prints suggests the dinosaur moved at an estimated speed of 3.5 to 4.5 miles per hour despite weighing more than seven tons. Researchers linked the prints to T. rex based on size, shape, and the surrounding rock layer, which has yielded numerous tyrannosaur fossils, including a juvenile specimen dubbed “Teen Rex” found nearby in 2022.

"Bones tell us an enormous amount about these animals, but footprints capture a moment of behavior," said Dr. Tyler Lyson, senior curator of vertebrate paleontology at the Denver Museum of Nature & Science.

The trackway was uncovered in 2025 on U.S. Forest Service land by Kent Hups, a high-school teacher and volunteer fossil hunter.

"As a teacher, I’m always telling my students that science starts with curiosity, passion and careful observation," Hups said.

Three of the four footprints are scheduled to be airlifted to the Denver Museum of Nature & Science later this year. The prints date to approximately 66.5 million years ago, near the end of the Cretaceous period, representing one of the last known movements of the species before the mass extinction event.