Contrary to its cinematic portrayal as a swift predator, the Tyrannosaurus Rex may have moved at a much slower pace, according to a new study analyzing fossilized footprints. Scientists suggest the king of the dinosaurs ambled along at approximately 3.5 to 4.5 miles per hour when the tracks were made.
The research, conducted by scientists from Liverpool John Moores University and the Denver Museum of Nature & Science, examined a 23-foot trackway found in North Dakota's Hell Creek Formation. This trackway features four three-toed footprints, each about three feet long. Based on their size and shape, researchers identified T. rex as the most likely maker.
"Bones tell us an enormous amount about these animals, but footprints capture a moment of behavior," explained Tyler Lyson, an author of the study. "With a trackway, we can actually follow an animal as it moved across the landscape. That is incredibly rare for T. rex."
Using 3D surface scanning, the team created detailed reproductions of the footprints. The analysis revealed a stride of approximately 13 feet, suggesting a walking speed between 3.5 and 4.5 mph (5.6 to 7.2 km/h). For comparison, the average walking pace for a fit person is around 4 mph.
Whether T. rex could run at higher speeds has been a subject of debate. Previous studies have offered conflicting conclusions, with one in 2017 suggesting its size and weight would prevent high-speed movement, while a more recent study proposed speeds up to 24.6 mph by running on tiptoes.
Lead author Professor Peter Falkingham stated that while it is hard to be certain from bones alone and a lack of sprinting trackways, T. rex could likely run. He also noted that the dinosaur's famously short arms may not have hindered its speed, drawing parallels to large birds like emus and cassowaries that run effectively with tucked wings.
This new analysis of T. rex's locomotion adds a different perspective to the popular image of the dinosaur, suggesting that early humans, had they coexisted, might have had a chance to outrun the massive predator during its slower gaits.