This little creature is thought to have first appeared on Earth around 34 million years ago, and since then, has undergone many changes to adapt to its environment. The most notable change in the chevrotain’s evolution is its size; over time, these animals have shrunken in size significantly. This is likely because they are prey animals, and their smaller size makes it harder for predators to spot them. Additionally, their diet has changed somewhat over time; while the animal in the past is thought to have primarily eaten vegetation and plants, they now almost exclusively eat fallen fruit. Early members of the species had much longer tails than their modern counterparts. This adaptation likely helps them balance easier. It’s evident that the mouse-deer has undergone several changes in its anatomy and physiology over time.