First Adult T. rex Trackway Discovered in North Dakota Badlands

In 2025, paleontologists working in the badlands near Marmarth, North Dakota uncovered something that had eluded the scientific community for more than a century of fossil hunting: a trackway left by an adult Tyrannosaurus rex. The discovery consists of four giant three-toed prints pressed into stone that is 66.5 million years old, a sequence that captures the actual movement of one of Earth's most formidable predators in a way that skeletal remains alone never could.

What makes this find extraordinary is not merely that the prints exist, but what they reveal about how this animal moved through the world. The stride between prints measures 13 feet—the distance from one footfall to the next—and from this measurement, paleontologists calculated that the T. rex was walking at a leisurely pace of 3.5 to 4.5 miles per hour. This was not a charging hunt or a desperate sprint. This was a creature simply moving through its landscape, covering ground at a walk.

Trackways are rare windows into behavior that bones cannot fully convey. A skeleton tells you what an animal was built to do; a trackway shows you what it actually did on a particular day, in a particular place, millions of years ago. Before this discovery, no confirmed adult T. rex trackway had ever been found. There were juvenile prints, there were isolated adult footprints, but never a sequence of prints from a full-grown animal that allowed scientists to measure stride length and calculate speed.

The Marmarth site, located in the North Dakota badlands, sits in the Hell Creek Formation, a geological layer rich with Late Cretaceous fossils. The region has yielded T. rex remains before, but finding the actual footprints of one—not bones, not teeth, but the physical impression left by its weight and movement—represents a different kind of evidence entirely. Each print is enormous, consistent with what we know about the size of adult T. rex feet, and the spacing between them tells a coherent story about locomotion.

The calculation of walking speed comes from a well-established formula in paleontology that uses stride length and estimated body size to determine velocity. At 3.5 to 4.5 miles per hour, this T. rex was moving at a pace comparable to a human stroll—not the explosive predator of popular imagination, but an animal that could cover considerable distance without exertion. This may reflect routine movement through territory, perhaps hunting or patrolling, or simply traveling from one location to another.

For paleontologists, the implications are significant. Trackways provide direct behavioral evidence that complements the skeletal record. They show how weight was distributed, how the animal balanced, the actual geometry of its gait. They answer questions that bones alone cannot: How did this creature really move? What was its typical pace? How did it navigate its environment? The four prints from Marmarth begin to answer these questions with a clarity that no museum display of fossilized bones can match.

This discovery also underscores how much remains to be found in the badlands and other fossil-rich regions. For decades, paleontologists have searched for trackways from adult T. rex, and the absence of such evidence was itself a puzzle. Now that one has been found, it raises the possibility that others exist, waiting in the rock layers for the right conditions of erosion and exposure to reveal them. The Marmarth trackway is not just a single remarkable find; it is proof that the evidence is there, preserved in stone, if scientists know where and how to look.