3D model simulates how dinosaurs ran

A computational zoologist at the University of Manchester, UK, has developed a new technique for simulating dinosaur movement in 3D and working out which gaits they most likely used.

According to a report in New Scientist, Bill Sellers and his team used a laser scanner to create a 3D computer model of the skeleton of an Edmontosaurus, a type of hadrosaur or "duck-billed" dinosaur, and added virtual muscles to make it move.

Fossilization does not preserve a dinosaur's muscles, but educated guesses about how they worked can be made by studying animals alive today, such as ostriches.

But, Sellers discovered that there's more to motion than muscles.

His team began by using a supercomputer to try out different patterns of muscle activity at random and pick the pattern that moved the dinosaur furthest forward in 5 seconds.

By slightly varying the most successful patterns and repeating the process thousands of times, the computer simulation produced a variety of possible gaits.

It turns out that a kangaroo-style hop on both legs gave a speed of 17 metres per second, while a four-legged gallop and two-legged run trailed at 16 m/s and 14 m/s respectively.

Now that Sellers could calculate the load on a dinosaur's skeleton during motion, he could work out the maximum possible size of its muscles, beyond which the animal's bones would have been damaged.

This in turn helps to determine what gaits it would have been capable of.

For the hadrosaurs, a four-legged gallop would also have put too much stress on their bones, so it is most likely they moved at slower speeds on four legs and reared up to run on two.

"The ability to simulate a variety of gaits in an extinct animal is exciting, but to get reliable bone stresses you need good muscle stresses and other data," said John Hutchinson, a biomechanics expert at the Royal Veterinary College in London.