The presented infographic depicts the evolution of the horse over a period of 40 million years, with a concentration on its foot structure.
Overall, the horse has grown more substantial in size with pronounced evolution of body parts over the course of 40 million years. Another noteworthy feature is that its toes have been transformed into one hoof.
Looking at the two first evolutionary phases, the horse existing 40 million years ago, named Eohippus, had a small body with a short tail and tiny round-edged ears, and its foot included four distinct toes which were slender. Besides, the horse found 10 million years later, called Mesohippus, had a body which was nearly two times larger than the former one. It was also more muscular with a longer tail and more prominent ears. Furthermore, there was an additional tuft of hair on its neck. Compared to its ancestor, each of its feet had lost one toe, and the middle one had grown noticeably larger.
Regarding the last 15 million years, the horse, also known as Merychippus, still extended in size and possessed 3-toe paws. In comparison with the one from 30 million years ago, its crest became denser and its 3 digits became heftier, especially the prominent middle one. Finally, the modern horse has become taller, larger, fully fledged with a full mane and a lot more hair on its tail. Moreover, the separate digits have merged into a single hoof, and the foot has much more developed fetlocks, which are capable of supporting a more enormous frame.