"The evolution of birds from their dinosaur ancestors represents one of the most important and widely used examples of evolution available from the fossil record. Within this dinosaur-bird lineage, the evolution of bipedal locomotion has proven to be an intensely active area of research. Most of this research has taken an almost exclusively osteological approach, but while the fossilised skeletons of extinct animals can tell us much about their anatomy and palaeobiology, it is fossilised tracks that represent our only direct record of limb kinematics and animal locomotion.A fossil track represents the only direct record of limb motion, being the result of an interaction between an animal’s foot and a substrate. Track morphology is completely determined by substrate consistency, limb kinematics and kinetics, and foot morphology. By reverse engineering the process of track formation, information can be obtained pertaining to the locomotion of the track maker.The proposed research aims to investigate the effects of differing limb motion on track formation, in an attempt to understand locomotor evolution throughout the 230 million year evolutionary history of theropods (including modern birds). This will be achieved by marshalling state-of-the-art methods including bi-planer x-ray visualisation in order to physically model tracks. A virtual ‘track simulator,’ based on the discrete element method for modelling granular substrates will then be developed to explore in detail the effects limb motion has upon track formation. This knowledge will then be applied to the fossil record to observe any changes attributable to limb kinematics and locomotor evolution through time."