While reviewing fossils of the Tyrannosaurus rex, paleontologists found large teeth marks that suggest bites from other T. rex dinosaurs. ((CBC))

The most feared of the dinosaurs, Tyrannosaurus rex, appears to have been cannibalistic, say scientists from the U.S. and Canada.

While reviewing the dinosaur fossils of the T. rex, paleontologists from Yale, the University of Alberta, Montana State University and Florida State University found large teeth marks that suggest bites from other T. rex dinosaurs.

"They're the kind of marks that any big carnivore could have made, but T. rex was the only big carnivore in western North America 65 million years ago," said Yale researcher Nick Longrich, in a news release. 

Longrich, a Canadian, found a number of examples of this type of cannibalism by reviewing other fossil collections in museums.

"It's surprising how frequent it appears to have been," Longrich said. "We're not exactly sure what that means."

The scientists believe that the marks were made when one dinosaur fed on another, perhaps at the culmination of a fight between the two predators.

"Modern big carnivores do this all the time," he said. "It's a convenient way to take out the competition and get a bit of food at the same time."

The researchers are buoyed by the findings, which they say offer insight into the largely unknown feeding habits of T. rex, which hunted alone.

The research was published Friday in the journal PLoS One.