Asked by: Leslie Waters, High Wycombe
Early horses such as Hyracotherium, which lived 55 million years ago, did have multiple toes, but they were much smaller animals. For taller animals, excess weight at the end of their legs has a much bigger impact on their speed. A recent study at Harvard found that one broad hoof is almost as strong as multiple smaller toes, but much lighter. Natural selection has gradually discarded the horse’s side toes and widened the middle one to increase running speed.