In 2011, a local hunting guide happened upon a tyrannosaur footprint in the Canadian wilderness.
When researchers began excavating, they found a long, skinny stretch filled with dinosaur tracks of several types, including several more tyrannosaur tracks.
Molding the feet
Researchers created moldings of the footprints to study them in more detail.
The three sets of tyrannosaur tracks were parallel to one another and all the same depth, suggesting the fierce predators moved together.
The tracks strengthen the theory that tyrannosaurs were pack animals.
Tyrannosaurs weren't the only animals to have left their mark. Smaller theropods also left prints in the area.
The tyrannosaurs narrowly missed their prey, as revealed by a track made by a hadrosaur that came through after the tyrannosaurs.
The hadrosaur also left a skin imprint in one of its tracks.
Recreating the walk
The footprints allowed researchers to recreate the tyrannosaurs' walk.
The tyrannosaur tracks were all created at the same time, suggesting the terrifying trio may have stalked prey together.
Tia Ghose, Senior Writer
Tia has interned at Science News, Wired.com, and the Milwaukee Journal Sentinel and has written for the Center for Investigative Reporting, Scientific American, and ScienceNow. She has a master's degree in bioengineering from the University of Washington and a graduate certificate in science writing from the University of California Santa Cruz.