for National Geographic News
Tyrannosaurus rex's fearsome reputation has taken another knock, with new research suggesting it was a slow-turning plodder.
The so-called king of dinosaurs has been buffeted in recent years by accusations of being a scavenger and a slowpoke.
Now a U.S. team suggests that T. rex also weighed considerably more than some experts had believed, took up to two seconds to turn 45 degrees, and is unlikely to have exceeded speeds of 25 miles (40 kilometers) an hour. (Related story: "Tyrannosaurus Rex Was a Slowpoke" [February 22, 2002].)
The study, led by biomechanics expert John Hutchinson while at Stanford University in California, is reported in the Journal of Theoretical Biology.
Building on previous work into the dino's biomechanics, the new findings challenge the perception that T. Rex was an athletic super-predator capable of running down fast, agile dinosaurs.
The team used a computer-modeling system to calculate the weight of a fossil specimen from the U.S. and then to estimate its running speed and turning ability, which has never been done before.
That fossil, an average-size adult, weighed between six and eight tons, and some individuals may have been as heavy as ten tons, the researchers said.
The team found the animal, hampered by a long tail and that heavy body, would have taken one to two seconds to make a quarter turn—far slower than a human.
"We now know that a T. rex would have been front-heavy, turned slowly, and could manage no more than a leisurely jog," Hutchinson, the lead study author, said.
Different Kind of Walk
Previous work by Hutchinson indicated that T. rex reached top speeds of between 10 and 25 miles (16 and 40 kilometers) an hour.
But the new study further undermines the popular notion that T. rex could reach speeds of around 45 miles an hour (72 kilometers an hour), as often depicted in movies.
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