T. Rex more like a hyena than a lion

USA Today Science Fair: T. Rex more like a hyena than a lion
The towering and terrifying Tyrannosaurus rex may have been less like a rampaging lion and more like a scavenging hyena, scientists conducting a census of dinosaurs say.

If T. rex were the apex predator of its day, it should have had been about one-third or one-fourth as abundant as its prey, because of the larger energy needs of carnivores. Instead, researchers doing a census of a major fossil site in Montana found as many T. rex fossils as herbivore fossils.

That makes the ferocious giant look a lot more like a hyena, an opportunistic hunter that eats already dead animals as well as fresh-killed prey. Hyenas are about twice as abundant as top predators in the African veld, said Mark Goodwin, a curator in UC Berkeley's Museum of Paleontology.

"In our census, T. rex came out very high, equivalent in numbers to Edmontosaurus, which many people had thought was its primary prey," John Horner, curator of paleontology at the Museum of the Rockies in Bozeman, Mont., and a professor at Montana State University, said in a release. "This says that T. rex is not a cheetah, it's not a lion. It's more like a hyena."

"If you count the lions and the leopards and the cheetahs in the Serengeti, the number still does not equal the number of hyenas, because hyenas have a much wider food source," Horner said. "Cheetahs, for example, only go after things that are really fast. They don't eat turtles. But a hyena will eat a turtle, or anything else that it can catch or is dead."

T. rex, he believes, was eating anything it could, he said. "There's no evidence that T. rex could run very fast, so it wasn't out there being a cheetah. If it could get a sick animal, it would."

The census was done of all dinosaur skeletons found over a large area of eastern Montana. Paleontologists began counting dinosaurs found in the Hell Creek Formation there, which dates from 65-95 million years ago, in 1999. The results are published in a paper in a February edition of open-access science journal PLos ONE.