for National Geographic News
Today's top athletes would be no contest for meat-eating dinosaurs that ran on two feet, according to new computer simulations of how the extinct predators moved.
Even a six-ton Tyrannosaurus rex, long considered a lumbering beast, could reach a top speed of 18 miles an hour (29 kilometers an hour), according to the simulations.
Fit athletes run just a fraction slower.
"Now I'm no slouch, I can run, but I think I'd end up being lunch for T. rex," said Phillip Manning, a paleontologist at Britain's University of Manchester.
Manning and co-author William Sellers describe the simulations in a paper published Wednesday in the journal Proceedings of the Royal Society B.
The simulations were created on a supercomputer model that crunches information on skeletal and muscular structure.
The program requires about a week to simulate the animals' method of movement, or gait.
"There are an awful lot of ways that you can activate muscles in a gait cycle, and the vast majority of them lead to an animal falling over very quickly," Sellers said.
The computer model takes the best gait cycle from each batch of about a thousand attempts as the starting point for each new batch, eventually finding the most likely simulation.
"It's a very good way of searching through effectively infinite space to find good solutions," Sellers said.
"Obviously, we can't guarantee these are the best solutions."
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