The most ferocious dinosaur that ever lived, the Tyrannosaurus Rex, was a cannibal, paleontologists believe.
Not content to chow down on every sauropod the fierce meat-eater encountered, Rex also took a chunk out of his fellow Tyrannosaurs as needed.
A T. Rex fossil bone discovered in Wyoming show what scientists believe to be the serrated teeth marks of another Tyrannosaur, the MailOnline reported.
Fossils found in the uppermost Cretaceous Lance Formation of Wyoming have been carbon-dated back 69 million years offering a panoply of scientific treasures.
"We were out in Wyoming digging up dinosaurs in the Lance Formation," paleontologist Matthew McLain of Loma Linda University said.
"Someone found a Tyrannosaur bone that was broken at both ends."
"It was covered in grooves. They were very deep," McLain noted.
The grooves in the Tyrannosaur bone fossil suggested that the meat was pulled off the creature with serrated teeth in a direction perpendicular to the bone, the paleontologists believe.
"'Serrated teeth rule out crocodiles and point directly to a theropod dinosaur like T. Rex," McLain elaborated.
"The fact that the only large theropods found in the Lance Formation are two tyrannosaurs -Tyrannosaurus Rex or Nanotyrannus Lancensis - eliminates all interpretations but cannibalism."
"This has to be a tyrannosaur. There's just nothing else that has such big teeth."