The image provided illustrates the evolution of the horse’s foot structure from forty millions years ago to present.
Overall, it is clear that the growth consists of four distinct stages,divided by the time period and the physical appearance, which is emphasized on the horse’s foot shapes. Moreover, the body structure has also changed dramatically.
The development began forty million years ago, at that time the horse used to call Eohippus, which is with both the smallest body frame and the most toes throughout the whole evolution stages. After ten million years, it is identified as Mesohippu. In these period, the body frame increased and started to have mane; however, the number of toes decreased to three and the joints became thicker. The next stage was Mcrychippus, by 15 millions years ago. With a similar appearance of recent horse, except the thiner tail and mane, as well as the foot.
Mcrychippus’ foot structure is almost the same with Meoshippus, despite the bigger size and the volume of joints. More recently, in the modern world, it turns to be known as Horse. Having hoof on the foot, with more hair of tail and mane.