Ah, T. Rex: Fierce ... ferocious ... fat?
Paleontologist John R. Hutchinson and colleagues led the study that suggested that the king of dinosaur was way plumper than previously thought:
“We knew she was big but the 30 percent increase in her weight was unexpected,” said Makovicky, who works at the museum where Sue has been a major draw since 2000. He added that this figure represents the leanest model, so the famous dinosaur might have been even more corpulent. “Nine tons is the minimum estimate we arrived at using a very skinny body form,” he explained.
The new mass estimates indicate that Tyrannosaurus rex grew twice as quickly as previously thought, packing on up to 3,950 pounds per year during the teenage phase. This staggering rate, coupled with its gargantuan adult proportions, probably meant that Tyrannosaurus rex moved more slowly as it aged, according to the researchers. Large individuals could still have achieved speeds between 10 and 25 miles per hour while running after prey, using their giant tail and hip muscles for propulsion, they said. Not bad for a hulking beast once thought to have weighed as much as a school bus or full-grown elephant—but may actually have verged on a bus with an elephant inside.