'Terrible lizards' were terrific runners

While it doesn't move so fast in movies, Tyrannosaurus Rex was quick enough to have most humans for lunch, according to supercomputer models at the University of Manchester.

While it doesn'tmoveso fastin movies, Tyrannosaurus Rex was quick enough to have most humans for lunch,according to supercomputer models at the University of Manchester.

Performing studies of "dinosaur gait modelling,"Britishand U.S. researchers produced computer simulations indicating the running speed of a variety of carnivorous dinosaurs, from the three-kilogram Compsognathus to the six-tonne T. Rex. They found that someof these "terrible lizards"— the term "dinosaur" coming from theGreek deinos (terrible) and sauria (lizard)— were terribly fast.

According to the study, the Compsognathus could have reached a speed of nearly 64 kilometres per hour — nearly eight km/hour faster than the ostrich, the world's fastest living creature on two legs.

By comparison, Canadian sprinter Donovan Bailey hit a top speed of 43 km/h while setting a world record in the 100 metres at the 1996 summer Olympics.

The T. Rex was not nearly so fleet-footed, but the computer models showed it was still fast enough to outrun most humans— if they had walked the Earth at the same time, which they didn't.

Results showed T. Rex capable of speeds up to 28.9 km/hour. For the sake of comparison, the researchers also entered data for a 70-kilogram human with the muscle and bone structure structure of a professional soccer player. The soccer player reached a top speed of 28.4 km/h.

How fast is a 6-tonne chicken?

The research team, headed by biomechanics expert Bill Sellers and paleontologist Phil Manning, say their results are likely the most accurate ever because of the computer's ability to use data relating directly to each dinosaur.

Using information gleaned from dinosaur skeletons, a powerful computer took up to a week learning how to "run" like each animal — starting with the first steps and eventually figuring out the optimum stride and posture to achieve a top running speed.

Sellers said most earlier information on a T. Rex 's speed came from estimates based on a six-tonne chicken, but pointed out that dinosaurs were built differently and would run differently.

Previous research has shown a six-tonne chicken would need more than 60 per cent of its total muscle mass in its legs in order to actually run — a physical structure that is physiologically implausible at best. Assuming they could run, computer models gave them a top speed around 17 km/h.

The study was published online Wednesday in the Proceedings of the Royal Society B.