T-rex versus Beckham? Sorry, David, you're lunch

By Michael Kahn

LONDON (Reuters) - The smallest dinosaur could reach speeds of nearly 40 mph (64 kph) and even the lumbering Tyrannosaurus rex would have been able to outrun most modern-day sportsmen, according to research published on Wednesday.

Scientists using computer models calculated the top speeds for five meat-eating dinosaurs in a study they say can also illustrate how animals cope with climate change and extinction.

The velociraptor, whose speed and ferocity was highlighted in the film "Jurassic Park," reached 24 mph while the T-rex could muster speeds of up to 18 mph, the study published in the Royal Society's Biological Sciences showed.

"Our research, which used the minimum leg-muscle mass T-rex required for movement, suggests that while not incredibly fast, this carnivore was certainly capable of running and would have little difficulty in chasing down footballer David Beckham, for instance," said Phil Manning, a paleontologist at the University of Manchester, who worked on the study.

The smallest dinosaur -- the Compsognathus -- could run nearly 40 mph, about 5 mph faster than the computer's estimate for the fastest living animal on two legs, the ostrich.

A top human sprinter can reach a speed of about 25 mph.

The researchers used a computer model to calculate the running speeds of the five dinosaurs that varied in size from the 3-kg (6.6 pound) Compsognathus to a six-tonne Tyrannosaurus.

They fed information about the skeletal and muscular structure of the dinosaurs into the computer and ran a simulation tens of millions of times to see how fast the animals moved, said William Sellers, a zoologist at the University of Manchester, who led the study.