T. rex Walked at 4–5 mph, Study of 65-Million-Year-Old Footprints Reveals

A newly published study examining 65-million-year-old fossilized footprints has determined that Tyrannosaurus rex moved at a walking pace of 4 to 5 miles per hour (6.4 to 8 km/h), a speed within reach of an average human runner.

Footprint evidence from South Dakota

The conclusion follows detailed analysis of a 23-foot-long (approximately 7 meters) trackway discovered in the Hell Creek Formation in southwestern North Dakota. The site contains four three-toed footprints, each measuring roughly 3 feet (about 1 meter) in length. Researchers attribute the prints to Tyrannosaurus rex—commonly known as “T. rex” or “the tyrant lizard king”—based on their exceptional size and narrow, three-fingered morphology.

Speed estimates based on stride and gait

Scientists from Liverpool John Moores University and the Denver Museum of Nature & Science calculated the dinosaur’s locomotion speed at between 3.5 and 4.5 mph (approximately 5.6 to 7.2 km/h) when it made the tracks. Lead author Professor Peter Falkingham stated: “The tracks indicate it was moving at about two meters per second, or around 4–5 mph. That’s slightly faster than most people walk. You’d probably need to break into a jog to keep up with it as it left these prints.”

Footprints as behavioral snapshots

Tyler Lyson, a co-author of the study, emphasized the unique value of trace fossils: “Bones tell us a great deal about these animals, but footprints preserve a moment of behavior. Thanks to this trackway, we can follow the dinosaur step by step as it moved—a rarity for Tyrannosaurus rex.”

Human locomotion compared

For context, the average walking speed of a person in excellent health is 4 mph (about 6.4 km/h), while the average running speed is approximately 6.7 mph (about 10.8 km/h). This comparison confirms that a human could outpace T. rex simply by running.

Ongoing scientific debate over T. rex speed

Whether T. rex could run at high speeds remains contested among paleontologists. A 2017 study from the University of Manchester argued that its massive body size and weight would have precluded rapid movement. In contrast, an earlier study released this year proposed the animal could reach sprinting speeds of up to 24.6 mph (39.59 km/h) while running on its toes. Professor Falkingham acknowledges the possibility that T. rex could run—but notes there is no definitive evidence confirming it.

Short arms did not hinder locomotion

Regarding T. rex’s famously short forelimbs, Falkingham observed they would not have impeded movement. He added: “If anything, the absence of swinging arms may have been an advantage—consider the emu and cassowary, both of which have relatively short arms held close to the body while running, with no difficulty achieving high speeds.”