The Mesohippus is the ‘middle horse’ and earned this name because they are the link between the eohippus-type horses of the Eocene and more ‘modern’ horses of today. They come from the northern woodlands of North America around 37 – 32 million years ago.
The Eocene equidae had four toes on their front feet and our little ‘middle horse’ developed without the fourth toe, creating a foot that would later become hooves of today.
The Mesohippus also showed a distinct change in their teeth, more of their teeth developed as molars (large & square for grinding food). This is thought to reflect a shift to a more varied diet, perhaps including fruit, leaves & grasses.
Many of these changes in physiology are simply nature and survival of the fittest taking its course. The Mesohippus do represent an important link between the smaller forest dwellers of the Eocene eopch and the larger, plains dwellers that dominated later during the Pliocene & Pleistocene. Be sure to learn about some of the other extinct Equidae like the Orohippus, the Eohippus & the Quagga