Active Plants, Animals & Ecology

Mud to muscles: Dinosaur-bird locomotor evolution from fossil footprints

In plain English

AI plain-English summary

Fossil footprints are revealing how dinosaurs shifted their walking style as they evolved into birds. The problem is that skeletons alone cannot show how extinct animals actually moved. While bird skeletons are clearly different from their dinosaur ancestors—with shorter tails and rearranged leg muscles—scientists do not know whether these changes happened gradually or in sudden bursts, or whether birds sacrificed efficient walking to gain the ability to fly. This project fills that gap by treating footprints as direct records of motion. The researcher will combine 3D imaging, lab experiments where animals walk on sediment, and supercomputer simulations that model every grain of sand as a foot presses into it. These simulations will calculate the forces between foot and ground, then feed into musculoskeletal models that reconstruct how whole limbs and bodies moved. By sampling fossil tracks spanning 230 million years, the project will recover the actual sequence of locomotor changes along the dinosaur-bird lineage. This is fundamental science with no immediate practical application. But understanding how limb mechanics evolve under competing demands—walking versus flying—could eventually inform the design of legged robots or prosthetics that must balance multiple modes of movement.

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Fossil footprints are a direct record of motion in a way that skeletons can never be. I will use fossil footprints to explore the locomotor changes that took place as birds evolved from theropod dinosaurs. Compared to their dinosaur ancestors, birds have a much-reduced tail and associated musculature. Did birds "give up" terrestrial locomotor superiority in order to fly? Are evolutionary changes in limb motions recorded in the fossil footprint record? If so, do they show a gradual change from tail-driven theropods to knee-driven birds, or do limb motions change abruptly with the appearance of specific traits? From mud to muscles, I will combine advanced 3D imaging, physical experimentation, and computer simulation to bridge the existing gap between fossil footprints and fossil skeletons, shedding light on this important evolutionary transition. Lab-based footprint-making experiments will combine kinematic and kinetic analyses to build an unprecedented view of footprint formation. Limb motions of long-extinct dinosaurs will be reconstructed using fossil tracks, then supercomputer simulations modelling every grain of a sediment responding to the indenting foot will be used to test the reconstructed motions. These simulations will compute the forces occurring between foot and ground. These forces and motions will drive musculoskeletal biomechanical simulations that will shed light, not only on what the feet of dinosaurs were doing, but on how the whole limbs and even bodies of these enigmatic animals once moved. By sampling fossil tracks from around the world, spanning the 230 million years since theropods first appeared, this project will recover fossilised motions along the dinosaur-bird lineage. Using rigorous, innovative methods, my proposal will unlock quantitative analysis of the way extinct animals moved, facilitating direct comparison with their extant descendants, and providing a unique view of locomotor evolution that cannot be recovered from bones alone.

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Researchers

Peter Falkingham (Principal Investigator)

Related Research

Grants with similar aims, by meaning.

Evolution of Body Form, Posture, and Locomotion in Birds and Dinosaurs
Computational biomechanics, functional anatomy and the evolution of dinosaur quadrupedality
Using avian bone histology to trace back the evolution of flight-related locomotor ontogeny in the dinosaur–bird transition
Digital Conservation and Reconstruction of 'Fossilized Behaviour': the evolution of the human foot as revealed by ancient footprint trails
Tetrapod limb ecomorphology inferring ecology during dinosaur-bird transition

Original classification

Research Grant

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