The Tyrannosaurus rex, a dinosaur that lived more than 70 million years ago, matured much faster and was a fiercer predator than previously thought, a recent study conducted by a team of British and U.S. scientists reveals.

The team of paleontologists said on Wednesday that the tyrannical lizard may have weighed more than 9 tons: This means the beasts was 30 percent heftier than previously estimated. The team compared four adult skeletons with a younger and smaller specimen to come to their conclusion.

They grew as fast as 3,950 pounds (1,790 kilograms) per year during the teenage period of growth, which is more than twice the previous estimate, John Hutchinson, a study researcher at the Royal Veterinary College in London, said in a statement.

The study involved Sue, the largest and most complete Tyrannosaurus rex specimen in the world, currently on display at the Natural History Museum in Chicago. The skeleton, which is 42 feet long and 13 feet high, at the hips, was named after Sue Hendrickson, a paleontologist.

We knew she was big but the 30 per cent increase in her weight was unexpected, said co-author and curator of dinosaurs at the Field Museum of Natural History in Chicago, Peter Makovicky.

At their fastest, in their teenage years, they were putting on 11 pounds or 5 kilograms a day, Hutchinson told Reuters.

The present study suggests Sue, that fearsome carnivore, had a huge appetite and a high metabolic rate. While earlier studies were equally clear about the fact that the T-rex had an enormous appetite, the latest study indicates that these animals used to eat 11 to 15 kilograms of meat every day.

The Present Study on Sue - the Giant Predator

In the present study, researchers created the largest and most complete digital 3D model of these giant predators. The paleontologists believe that the scanning these 40 feet skeletons with lasers produced measurements that were accurate to within half an inch. The task of scanning the skeleton was possible due to help from the Chicago Police Department and the Ford Motor Company, the researchers added.

After scanning the skeletons, researchers estimated the body volume by covering the digital models with digital skin.

The real advantage to our method is that the models can be adjusted to accommodate the variation that is inherent in nature, so we don't have to pick an arbitrary result, but rather deal with more meaningful ranges of results, said co-author Karl T. Bates of the University of Liverpool.

Previous methods for calculating mass relied on scale models, which can magnify even minor errors, or on extrapolations from living animals with very different body plans from dinosaurs. We overcame such problems by using the actual skeletons as a starting point for our study, Makovicky said.

However, the giant size indicates that the speed of the predator could not have been more than 10-25 miles per hour.

It's not super-fast but they were no slouches, Hutchinson said.

The finding was published in the journal PLoS ONE.