Looking at Dinosaur Gaits 

How did dinosaurs walk? Or more specifically what was their gait? In which order did they move their legs? THIS ARTICLE looks at the long-necked dinosaurs, the largest creatures to walk on the Earth's surface.

Fossils are not much help - you can only tell so much from bones - what you need are tracks! But that is not conclusive.

The authors tell us that, if we do not know the distance from hip to shoulder - the trunk length - we could not identify the gait. But if the speed of the dinosaur changes along a track and we assume a gait change we calculate a different trunk length. The gait which gives the most consistent trunk length is assumed to be the correct gait.

This was applied to modern animals and it worked! When it was applied to dinosaur tracks (from the Cretaceous of Arkansas) it was found that the giant beasts did not walk the same way as modern elephants, which came as a surprise.

Elephants employ lateral couplets gaits – they tend to move the fore and hind limb of the same body-side together - see illustration.

The lateral couplets gait, seen in animals such as elephants. Jens Lallensack, Author provided

The sauropods had a diagonal couplets gait - see illustration.

Why the difference? Sauropods are wider than elephants. Elephants set their feet almost in front of each other. Sauropods, if they did the same, would have to sway from side to side and this would be very unstable.