First Adult T. rex Trackway Found in the North Dakota Badlands

Paleontologists have described the first known trackway made by an adult Tyrannosaurus rex: four large, three-toed footprints stretching roughly 7 metres (23 feet) across a site in the Hell Creek Formation of southwestern North Dakota. Each print is about a metre (3.3 feet) long. The findings were published this week in the Journal of Vertebrate Paleontology.

The site dates to about 66.5 million years ago, in the latest Cretaceous, shortly before the asteroid impact that ended the dinosaurs' reign. The prints sit in unusual preservation: as hardened, calcium-carbonate-cemented sandstone casts that formed around depressions left in soft, muddy overbank sediment. Erosion later stripped away the softer surrounding rock, exposing the harder casts — a process that left the surfaces heavily fractured, so the prints preserve little anatomical detail beyond size and toe count.

What makes the attribution to an adult T. rex credible is the combination of evidence. The footprints' size and shape, the narrow angle between the toe impressions, and the abundance of T. rex bones already recovered from the surrounding rock all point to the same conclusion. Isolated tracks had previously been linked to tyrannosaurs — one described in New Mexico in 1994, another in Montana in 2008 — but none had recorded more than a single footprint from an animal believed to be fully grown. Other tyrannosaur trackways from Canada and Wyoming were made by smaller animals.

Spacing between the prints — a stride of roughly 4 metres — let the team estimate the animal was walking at about 1.5 to 2 metres per second (3.4–4.5 mph), consistent with other large theropod trackways. The trackway was discovered in 2025 by Kent Hups, a high school teacher, who happened to be in the right place at the right time; Denver Museum of Nature & Science curator Tyler Lyson joined the excavation and is a senior author on the paper. "Bones tell us an enormous amount about these animals, but footprints capture a moment of behavior," Lyson said. "With a trackway, we can actually follow an animal as it moved across the landscape."

The discovery is a reminder of how thin the ichnological record for the most famous dinosaur remains: a single stroll across a mudflat is now the best evidence of how an adult T. rex actually moved.