It would have been a terrifying sight for a leaf eater: not one, but three adult tyrannosaurs, moving purposefully in one direction.
Fortunately for scientists, the gang of meat eaters took a romp through a patch of volcanic ash, preserving their tracks for as many as 72 million years.
Paleontologists in Tumbler Ridge have made an unprecedented discovery of three intact tyrannosaur trackways. The trackways are believed to belong to separate dinosaurs, and suggests that the three meat eaters were walking together in the same direction.
According to Lisa Buckley, one of the paper's lead authors, the tracks are some of the only solid evidence we have of social behaviour among tyrannosaurs.
"They were walking in the same direction around the same time," said Buckley. "One would be a terrifying sight - three would just be horrific. You would not want to be prey at that moment."
The implications of the find were published Wednesday in the Public Library of Science journal.
A local outfitter named Aaron Fredlund discovered the tracks over a year ago and reported them to the Peace Region Paleontology Research Centre. Since then, scientists have been poring over the tracks.
Each trackway has between two and three footprints. The prints belonged not to a T. Rex, but a smaller creature from the same family, possibly an Albertosaurus.
The dinosaurs, which lived during the late Cretaceous period, had a stride of around three meters, and stood around 2.8 meters high at the hip. Prior to this discovery, there was scant evidence that tyrannosaurs lived together.
One bone bed in an Alberta provincial park contained several sets of tyrannosaur bones. But Buckley points out that the bones could have been moved due to erosion, water or glacial activity - raising questions about whether the animals actually lived together.
Scientists have also discovered tyrannosaur skeletons with bite marks from other tyrannosaurs - evidence that the animals attacked members of their own species.
The Tumbler Ridge discovery is the most compelling evidence we now have of social behaviour among tyrannosaurs, Buckley said.
Dr. Charles Helm, head of Tumbler Ridge's push to get the area certified with the UN as a Global Geopark, said scientists have been chomping at the bit to publicize the find.
If Tumbler Ridge wins UN approval, it will join a global network of around 90 sites of global geological significance.
"The timing is great," Helm said. "This just strengthens our geopark proposal. This is an internationally significant site."
Because the site is so fragile, there are no plans to open it up to public viewing at this time. Buckley said the location of the find is being kept secret pending changes to how B.C. protects fossils.
"Right now in B.C., the status of fossil protection is still in the works. There is no specific protection for fossils in B.C. unless they're in a provincial park, and this is not in a park," she said.
The lack of fossil protection laws are just one of the ways paleontology in Tumbler Ridge is a new frontier. The Peace Region Paleontology Research Centre runs on a shoestring budget and gets its only operating funding from the local government and the regional district, Helm said, adding that this find is evidence of how the centre punches above its weight.
"We're continually amazed by what our scientists are able to do. They get massive results," he said. "They don't even know year by year where the funding is going to come from."
The next step is to uncover more of the tracks, said Buckley, as they travel underneath a nearby hill. The biggest question at this point is whether they'll have the funding to complete the work.
"I'm sure there are several discoveries of this magnitude just waiting to be found in the province," she said. "But if we don't have the funding to go after them, they remain hidden."
The UN delegation that visited Tumbler Ridge this spring to review its geopark application is expected to deliver a verdict on Sept. 22.
