First known adult T. rex trackway found in North Dakota

Four fossilized footprints in North Dakota have given paleontologists the first known trackway likely made by an adult Tyrannosaurus rex. The roughly 23-foot sequence preserves something bones cannot: a brief record of the animal walking across a muddy landscape about 66.5 million years ago.

Each three-toed print is about 3 feet long. Their size, narrow toe shape and location in the fossil-rich Hell Creek Formation led researchers to identify a full-grown T. rex as the most likely trackmaker. The sequence contains two left and two right prints, with a stride of about 13 feet. Based on their spacing, researchers estimate the dinosaur was moving at roughly 3.5 to 4.5 miles per hour, although weathering makes that calculation uncertain.

A high school teacher volunteering on a museum fossil dig discovered the trackway on federal land near Marmarth in 2025. Researchers then recorded the fractured sandstone casts with high-resolution 3D scanning. The digital data allowed a dinosaur-track specialist in England to examine the site remotely and helped the team produce physical models.

Only two isolated adult T. rex footprints had previously been confirmed. This connected sequence offers the first opportunity to trace several consecutive steps by one of the largest predators of the Cretaceous period.