First adult T-Rex footprint discovered in North Dakota

In the US state of North Dakota, a team of researchers has found successive tracks that, according to analysis, were left by a Tyrannosaurus Rex in North America around 66.5 million years ago.

A total of four are lined up in the so-called Hell Creek Formation near the town of Marmarth, two on the left and two on the right, as the research team reports in the Journal of Vertebrate Paleontology. It is the first known sequence of several footsteps of an adult T-Rex.

"Bones tell us a tremendous amount about these animals, but footprints capture a moment of behavior," said co-author Tyler Lyson of the Denver Museum of Nature & Science. This allows you to follow the animal as it moves through the landscape.

The heavily weathered prints, which are between 60 and 80 centimeters wide, reveal the three toes on each of the giant dinosaur's hind feet. Based on the distance between the steps and the size of the prints, the researchers calculated that the animal was about four meters tall at the waist. They also estimate that the T-Rex was traveling at a speed of around 5 to 7 kilometers per hour. This corresponds to a brisk human walking pace.

According to the information, the fact that the prints were preserved is due to a special creation process: When the animal ran over soft ground, it left depressions that filled with sandy material. Calcareous groundwater solidified the contents and edges of the prints over time. Later weathering and erosion washed away the surrounding, softer rock, exposing the fossilized tracks.