About This Project

Given how fast horses move it is crazy to think that millions of years ago the horse foot underwent a remarkable transformation, from three toes with soft-pads to just one toe encased in a tough hoof. Concentrating all that force onto one toe seems risky. This project aims to determine how over millions of years the internal structure of the foot bones altered to cope with this dramatic change in the number and position of the toes.

Ask the Scientists

What is the context of this research?

Evolution of the horse foot is a remarkable and classic example of adaptation that has featured in many popular science books and documentaries. About 55 million years ago, the ancestors to the modern horse had three toes on each foot and roamed wooded areas. Extensive climatic cooling and drying then heralded the rise of grasslands and horses became larger, elongated their legs, and changed their foot posture to standing on the tips of just one toe per foot. This change is interpreted as allowing for faster and more efficient running. However, despite the net benefit of this anatomy, the concentration of forces onto just one toe can have major repercussions for modern horses – the bones are much more likely to fracture resulting in death.

What is the significance of this project?

An understanding of how the horse foot withstood and dissipated forces at key stages in its evolutionary history is crucial to understanding the morphology of living horses and the remarkable transition of foot morphology seen during the preceding 50 million years.

Research also has implications for equine veterinary work, as the foot bones can fail catastrophically amongst, for example, race horses. A better understanding of the factors shaping the evolution of these structures is an important context to understanding these common injuries.

What are the goals of the project?

This project will examine in detail one particularly important foot bone - the proximal phalanx. This will be investigated in both the extinct three toed horses and modern domestic horses (one toe). Goals are:
1) collect 8 Anchitherium and 8 modern domestic horse phalanx bones from various museums
2) image the bones using micro-computed tomography (this is the biggest cost)
3) reconstruct the bones in 3D within a computer (using freeware like 3Dslicer)
4) use the freeware FEBio software to virtually simulate how forces would propagate through the bone as the foot hits the ground.
5) Write up results and publish in open access format