Tyrannosaurus the cannibal

Jeff Poling

When people imagine a Tyrannosaurus rex attack, they imagine the victim as a helpless hadrosaur or a battling Triceratops. But evidence from recently excavated T.rex bones indicates that these animals frequently turned their six-inch-long teeth and deadly claws upon each other. Like lions in the Serengetti plain, T.rex individuals and family groups may have engaged in brutal combat as they fought for supremacy over choice hunting grounds. They may even have practiced cannibalism on others of their own species.

This new view of T.rex comes from three fossil skeletons unearthed over the last five years by scientists at the Black Hills Institute of Geological Research in Hill City, South Dakota. The fossils were all found within a one-square-mile area in sedimentary layers separated by only a dozen or so yards, meaning the individuals lived within a few thousand years of one another.

Paleontologist and Institute president Peter Larson thinks this proximity in time and space isn't just a coincidence. In the late Cretaceous, 65 Ma ago, this locality was a lush environment of forests and streams, perfect for plant eaters and the carnivores that fed on them. Many modern predators fight for dominance over prime real estate, so it's easy to imagine T.rex having done so as well.

Larson points to horrific wound marks to indicate that T.rexes fought fierce battles over territory. A male specimen named "Stan" had a T. rex-tooth shaped hole in the back of his skull that later healed. The nearly complete female specimen named "Sue," discovered in 1990 and the subject of bitter legal battles for many years, suffered a non-fatal broken rib. Embedded in the broken and infected rib was a tooth fragment from another T.rex. Larson also found fatal wounds on the left side of her skull that were clearly the result of a T.rex bite. "'Sue's face was literally torn off by another T.rex" Larson says.

But perhaps the most intriguing insight into T.rex behavior comes from the latest find, a specimen named "Steven." Some of "Steven's" vertebrae were literally bitten in half, and the vertebral bones that connected to tenderloin and T. rex T-bone steaks are missing. The only known animal living at the time with large enough and strong enough jaws to bite through T.rex bone was T.rex.

According to Larson, this is the first evidence that T.rex may have feasted on its own kind. "We knew they fought each other, we knew they killed each other once in a while, but we didn't know they ate each other too," he said.

From: "Cunningham, Betty" {bcunning@nssi.com}

Hah! Long-time members of this list will remember I suggested something like this about territoriality for T rex especially.

Now, were all the bites from T rexes larger than the individual that was being bitten, or the same size as the individual being bitten? Same size could be breeding and territory related, larger to smaller could be dominance and territory related.