The first known set of footprints from an adult Tyrannosaurus rex has been found in North Dakota by a team of scientists. The 23-foot-long footprint, which consists of four three-toed prints, two on the left and two on the right, was first identified in the southwest of the state, in the area of dinosaur fossils known as the Hell Creek Formation, last year by researchers from the Denver Museum of Nature and Science in Colorado and Liverpool John Moores University in the United Kingdom. The findings, which have now been published in a scientific journal, date back to 66.5 million years ago and are the first of their kind to be found and identified. Although isolated footprints and footprints of juveniles or related species have already been found, this is the first known series of footprints left by a wandering T rex. “The bones tell us a lot about these animals, but the footprints capture a moment of behavior,” said Tyler Lyson, senior curator of vertebrate paleontology at the Denver museum. “With a footprint, we can follow an animal as it moves across the landscape. That’s incredibly rare for a T rex.” (0.91 m) long, with a stride of approximately 13 feet (3.96 m). The research team used high-resolution 3D surface scanning to document each footprint and create 3D physical reproductions. From this work, the researchers were able to make a rough estimate that the animal was walking at a speed of 3.5 to 4.5 mph, about the same as a human’s brisk walk. The T rex, the most famous of all dinosaurs, lived about 66 to 68 million years ago during the Cretaceous period, according to the known fossil record. The creatures, which stood between 12 and 13 feet tall, were among the last non-avian dinosaurs to walk the Earth before a mass extinction wiped them out. Three of the discovered footprints will be recovered by helicopter later this year and transported to the museum in Denver. The finds are a particular joy to the Colorado schoolteacher who stumbled upon the site. “As a teacher, I always tell my students that science begins with curiosity, passion and careful observation,” said Kent Hups, a longtime museum volunteer who also co-authored the paper. “I never imagined that could lead to a discovery like this.”
