PREVIEW

BY MARK WORGAN

Scientists have discovered what they say is the first trackway left by an adult Tyrannosaurus rex, offering new clues about how the fearsome dinosaur moved.

The sequence of four footprints was found in the Hell Creek Formation in south-western North Dakota and is thought to date back about 66.5 million years.

The trackway is about 23ft (7m) long, with each three-toed footprint measuring roughly 3ft (0.9m) in length.

Researchers from the Denver Museum of Nature & Science and Liverpool John Moores University said the footprints were most likely made by an adult T. rex because of their size and the narrow shape of the toes, as well as the abundance of T. rex fossils in the surrounding area.

Individual footprints have previously been attributed to adult T. rex, but the researchers said this was the first time a sequence of tracks had been described that was likely made by the species.

“Bones tell us an enormous amount about these animals, but footprints capture a moment of behavior. With a trackway, we can actually follow an animal as it moved across the landscape. That is incredibly rare for T. rex,” said Tyler Lyson, senior curator of vertebrate paleontology at the Denver Museum of Nature & Science.

The trackway was discovered in 2025 on federal land administered by the US Forest Service near Marmarth, North Dakota.

Researchers used high-resolution 3D surface scanning to record the individual footprints and the trackway as a whole.

The resulting digital models allow the tracks to be studied in detail and reproduced physically in three dimensions.

Peter Falkingham, professor of palaeobiology at Liverpool John Moores University and a specialist in dinosaur tracks, was lead author of the study.
He has not seen the footprints in person, but was able to examine them using digital scans produced by his colleagues in the field.

“The technology we’re able to apply in the digital age means my colleagues could scan the tracks in the field and then send the 3D information over to me to visualize on my computer and in VR, enabling me to take as close a look as they did in person,” he said.

The four footprints consist of two left and two right prints, with a stride of about 13ft (4m).
The researchers estimate that the dinosaur was walking at between 3.5 and 4.5mph (5.6-7.2km/h), a speed broadly comparable to a brisk human walking pace.

However, the tracks have been heavily weathered, meaning the speed estimate is approximate.

“As a teacher, I’m always telling my students that science starts with curiosity, passion, and careful observation. I never imagined that could lead me to a discovery like this,” said Kent M. Hups, a teacher at Northglenn High School who discovered the site and co-authored the paper.

Three of the footprints are due to be recovered by helicopter this autumn and transported to the Denver Museum of Nature & Science. The museum plans to provide updates on the recovery to visitors during the winter.

The research team also includes museum researchers Evan Tamez-Galvan and Antoine Bercovici.

Lyson led the fieldwork, while Mr Tamez-Galvan carried out the surface scanning.
The findings have been published in the Journal of Vertebrate Paleontology.