An adult T. rex left behind four steps that now make it possible to follow its walk, 66.5 million years later.
The trackway was discovered in 2025 in the Hell Creek Formation, in North Dakota, United States. It extends for approximately 7 m and includes two left-footprints and two right-footprints. Each one measures nearly 1 m in length. For the researchers, their size and shape very likely correspond to those of an adult tyrannosaur.
A Tyrannosaurus rex at the Palais de la Découverte, Paris
This attribution is not based solely on size. The tracks show three fairly narrow toes, characteristic of a large carnivorous dinosaur. Herbivorous dinosaurs living in the same region could also leave large three-toed footprints, but theirs were generally wider. Numerous T. rex bones have also been found nearby.
The main significance of this discovery lies in the succession of the steps. Isolated footprints attributed to adult T. rex were already known. A trackway provides something else: the distance between the steps reveals how the animal moved. This is the first known sequence that researchers can attribute to an adult with such confidence.
Here, the T. rex was not running. Its strides reached approximately 4 m, and the researchers estimate its speed at between 1.5 and 2 m/s. That corresponds to roughly 5.4 to 7.2 km/h, the pace of a person walking briskly. This estimate remains approximate because the footprints were deformed during their preservation.
Field photographs and elevation map diagrams of the Tyrannosaurus rex trackway (DMNH Loc. 21732).
To understand their current condition, we must go back to the moment when the animal placed its feet in wet ground. The depressions were then filled with sediment. Over time, this material became harder rock than the rock surrounding it. Erosion eventually exposed four rounded forms preserving the footprints.
The surfaces are now heavily cracked, and much of the detail of the feet has disappeared. Scientists therefore carried out highly precise 3D surveys in the field. These digital models make it possible to measure the trackway, examine it remotely, and even produce physical reproductions without immediately moving the rocky blocks.
The trackway thus provides information that skeletons cannot directly offer: a moment in the movement of a living animal. It cannot, however, reveal where this T. rex was going or why. Four footprints represent only a few seconds of its life and are insufficient to precisely reconstruct its entire way of walking.
Part of the story may still emerge from the ground. Three footprints must be recovered and transported to the Denver Museum of Nature & Science to be prepared and studied. The researchers also indicate that other steps may remain buried beneath the rock, but uncovering them would be difficult because of the thickness of the overlying terrain.