From the article of LiveScience.com:

The pick and shovel can go only so far in digging up details about dinosaurs. Now supercomputers are revealing knowledge about their anatomy otherwise lost to history.

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For example, if the muscles connected to the thigh bone of a Tyrannosaurus rex were short, that would suggest it was angled vertically as in humans. However, if they were very long, it could have been angled horizontally as in birds.

Initial attempts to randomly decipher which pattern of muscle activation works best result almost always in the animal falling on its face, explained computer paleontologist Peter Falkingham at the University of Manchester. But the scientists employ “genetic algorithms,” or computer programs that can alter themselves and evolve, and so run pattern after pattern until they get improvements.

Eventually, they evolve a pattern of muscle activation with a stable gait and the dinosaur can walk, run, chase or graze, Falkingham said. Assuming natural selection evolves the best possible solution as well, the modeled animal should move similar to its now extinct counterpart. Indeed, they have achieved similar top speeds and gaits with computer versions of humans, emus and ostriches as in reality.

Read the full article.