New Evidence of Bat-style Locomotion In Pterodactyls

The discovery of fossil footprints in Colorado, Utah, and Wyoming in the early 1990's may debunk this "bird hind-leg" theory. Bird-style footprints are distinctive because only the hind feet are used for walking, and the legs are close together under the body. They do not sprawl out sideways. Bird tracks are similar to those left by meat-eating dinosaurs—such as Allosaurus or Tyrannosaurus—with the right and left hind paws hitting the ground very close to the center line of the tracks. Bats, however, leave tracks from the forefeet as well as the hind feet, and the hind feet are splayed far out to the sides. Sprawled-out hind feet are necessary to hold out the trailing edge of the wing when the bat flies.

The newly discovered pterodactyl tracks show pterodactyls walking like giant vampire bats, with the arms and legs spread sideways. The wide spread of the hind legs is evidence that pterodactyl hind legs were attached to the wing. These tracks indicate that pterodactyls did not walk like birds.

More evidence for a bat-style locomotion comes from the tail bones of one of the largest pterodactyls, Pteranodon. The bones include special tail rods that probably attached to a rear wing extension running from tail tip to hind leg. And wing imprints from other pterodactyl species show that the trailing edge of the main wing was firmly anchored to the thigh and calf.