Tyrannosaurus rex may not have been the solitary predator depicted in films and books, say researchers who've uncovered fossilized tracks in Canada suggesting the giant creatures may have hunted in packs.
The concept of large tyrannosaurs working together to stalk and bring down their prey isn't new, but hard evidence has been scant -- until now.
The configuration of three dinosaur tracks discovered in British Columbia bear strong evidence of a dinosaur trio working together in a hunting effort, researchers wrote in the journal PLOS ONE.
"All three trackways show animals bearing southeast within an 8.5 meter-wide (27-foot) corridor," study leader Richard McCrea of the Peace Region Paleontology Center says.
"Similarities in depth and preservation of the tyrannosaurid tracks indicate that these three trackways were made by track-makers walking concurrently in the same direction."
The evidence suggests the giant dinosaurs, once considered solitary creatures, may have been more social and gregarious than previously thought and even have hunted together in "terror gangs," McCrea says.
The gargantuan predators may have "stuck together as a pack to increase their chances of bringing down prey and individually surviving," he says.
Such behaviors among hunting animals is seen today, he says.
"An individual wolf would not be able to take out a moose, but a pack of them would," McCrea says.
Hunting in groups would allow the tyrannosaurs to hunt prey such as the duck-billed dinosaurs known as hadrosaurs, which were almost as big as the tyrannosaurs.
Seven different trackways showing footprints of the three tyrannosaurs tougher were eventually identified at the fossil site in Northeastern British Columbia, the researchers said.
The parallel tracks, made as the animals moved across a mud flat around 7 millions years ago, were preserved by a thick layer of volcanic ash that covered the footprints, they said.
The exact species leaving the footprints is unknown, since at least three different species of tryannosaurs -- Gorgosaurus, Albertsosaurus and Daspletosaurus -- lived in the region of the Canadian Rockies when they prints were laid down, the researchers point out.
The size of the footprints indicates all three of the hunting tyrannosaurs were adults.
Although the exact species has not been identified, the researchers have labeled the tracks Bellatoripes fredlundi, as homage to their "warlike foot" shape and to Aaron Fredlund, a local hunting outfitter and guide who first spotted the tracks in 2011 and alerted the paleontologists.
