Scientists Unearth Evidence of Tyrannosaur Cannibalism in Gnawed Bone

Posted on November 1, 2015

Scientists have unearthed fossil evidence that tyrannosaurs would at least sometimes eat other tyrannosaurs. An unearthed tyrannosaur bone has teeth marks that suggest it was gnawed by another tyrannosaur.

Paleontologist Matthew McLain of Loma Linda University in California says in a statement, "We were out in Wyoming digging up dinosaurs in the Lance Formation. Someone found a tyrannosaur bone that was broken at both ends. It was covered in grooves. They were very deep grooves."

The researchers say the grooves in the bone are from an animal pulling flesh off the bone. The grooves pull in a direction perpendicular to the bone in the same way a human would eat fried chicken. One of the grooves contains smaller parallel groves that were made by the serrated edges of the animal's teeth dragging across the bone. The serrated teeth rule out crocodiles and point directly to a theropod dinosaur like T. rex.

Mclain says the fact that the only large theropods found in the Lance Formation are two tyrannosaurs - Tyrannosaurus rex or Nanotyrannus lancensis - eliminates all possibilities but cannibalism. He says, "This has to be a tyrannosaur. There's just nothing else that has such big teeth."

The grooves in the bone do not indicate whether the tyrannosaur was scavenging and eating an already dead tyrannosaur carcass or whether one tyrannosaur killed another.

McLain present on a research paper on the tyrannosaur cannibalism fossil discover at the 2015 Geological Society of America (GSA) Annual Meeting in Baltimore.

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