A new study concludes that dinosaurs like the Field Museum's famous Sue went through enormous growth spurts during their teen years.
Of course, if human teenagers went through a size explosion similar to T. rex, a 14-year-old boy weighing 125 pounds would tip the scales at 625 by prom, reports Suntimes.com
According to TheGlobeAndMail.com during explosive teenaged growth spurts, Tyrannosaurus rex larded on almost 2.1 kilograms a day, but the ferocious carnivores didn't live to see their 30s, according to a new study.
"It looked like T. rex lived fast and died young. The James Dean of dinosaurs," said Gregory Erickson, a professor at Florida State University in Tallahassee, who devised a way to track the creature's growth rate.
Like trees, the bones of modern-day reptiles and the extinct tyrannosaurids have growth rings that reveal annual growth cycles and age.
Dr. Erickson, along with American and Canadian researchers, examined more than 60 bones from 20 fossils of closely related tyrannosaurids dating back more than 65 million years.
Guardian.co.uk informs the first dinosaurs to evolve 225m years ago were small creatures, only a few feet long. The last dinosaurs, more than 150m years later, were colossal.
T rex in particular has had palaeontologists scratching their heads for decades. The monster is equipped with a 6ft skull, huge jaws, and a pathetic little pair of forearms so short it could not even pick its own teeth.
The big questions have always been: how did it get so huge? And was it a predator, or a scavenger?
The US researchers used a cross-section of leg bones to calculate the mass of each specimen in the American collections. Then they used a new technique to count the annual growth rings in other bones belonging to a whole collection of the tyrannosaur family. They were then able to match age against weight gain, and identify the "teenage spurt" that took T rex into the heavyweight class.