Adult T-rex footprints reveal prehistoric walking speed
First known trackway shows the predator moved at human walking pace
1Historic trackway discovery
A sequence of four fossilized footprints spanning seven meters in North Dakota's Hell Creek Formation represents the first known trackway from an adult Tyrannosaurus rex. Discovered by high school science teacher Kent Hups during a volunteer dig, these 66.5-million-year-old prints provide unprecedented evidence about the dinosaur's locomotion. Unlike isolated footprints found previously, this continuous trail allows scientists to analyze stride length and foot placement patterns. The tracks were preserved when mud filled the depressions and hardened into sandstone over millions of years.
2Walking speed calculation
Analysis of the trackway reveals the T-rex moved at 1.5 to 2 meters per second - comparable to a brisk human walking pace. Each meter-long footprint displays characteristic T-rex features: tridactyl shape, narrow toe angles, and proportions matching adult specimens from the area. The 13-foot stride length provided crucial biomechanical data, though surface fracturing erased finer skin or pad details. Researchers confirmed the identification through the prints' scale and the abundance of T-rex skeletons found nearby in the same geological formation.
3Unique preservation process
The footprints survived through an unusual geological process where the dinosaur's steps in soft mud were filled with sediment that hardened over millennia. This created three-toed sandstone casts protruding from a hillside in the fossil-rich Hell Creek Formation. The site lies approximately 33 meters below the Cretaceous-Paleogene boundary layer, dating the tracks to just before the asteroid impact that wiped out dinosaurs. The steep slope where they were found suggests the T-rex was navigating varied terrain when it left these traces.
4Behavioral snapshot
Unlike skeletal remains that show anatomy, these footprints capture a moment of the T-rex's living behavior. Dr. Tyler Lyson of the Denver Museum notes trackways allow scientists to follow an animal's actual movement across the landscape - exceptionally rare for T-rex specimens. The discovery team, led by Dr. Peter Falkingham, emphasizes how age affects gait mechanics in dinosaurs, similar to human developmental differences. The casual walking pace contradicts some previous assumptions about constant high-speed hunting behavior in adult T-rexes.
5Discovery circumstances
Kent Hups, the high school teacher who first spotted the prints, found them while exploring a steep slope during an expedition led by Dr. Lyson. Hups describes the discovery as proof that scientific breakthroughs begin with curiosity and careful observation. The site continues to be excavated, with researchers suspecting a fifth footprint remains buried, waiting for natural erosion to safely reveal it. This find highlights how volunteer contributions and systematic surveying can lead to major paleontological breakthroughs in well-studied formations.
6Scientific significance
This trackway provides the first direct evidence about how adult T-rexes moved through their environment. The walking speed data helps refine biomechanical models of dinosaur locomotion and energy expenditure. Being made shortly before the mass extinction event, these tracks offer a rare snapshot of T-rex behavior at the end of the Cretaceous period. Researchers can now compare these adult movement patterns with known juvenile tracks to better understand developmental changes in the species' locomotion capabilities.
7Research methodology
The study combined traditional fossil analysis with modern biomechanical modeling. Researchers measured stride length, footprint depth, and spacing to calculate speed, while comparing the tracks to skeletal remains for age verification. The team used the site's geological context - positioned below the K-Pg boundary - to precisely date the tracks. Dr. Falkingham's team emphasized how such trackways complement skeletal studies by providing dynamic behavioral data impossible to obtain from bones alone.
8Future implications
This discovery establishes a new benchmark for understanding T-rex locomotion and behavior. Future research can compare these findings with trackways from other dinosaur species to reconstruct prehistoric ecosystems more accurately. The ongoing excavation may reveal additional footprints, potentially showing changes in speed or direction. As Hups' experience demonstrates, such finds underscore the continued potential for major discoveries even in extensively studied fossil beds through persistent, observant fieldwork.
Original article: The Independent Science — Adult T-rex footprints reveal prehistoric walking speed