The evolution of horses is perhaps one of the most unusual evolution stories in nature. Horses seem to have gone in several different directions when it came to evolution. At times they even seemed to reverse or go backwards in their development, depending on the needs of the environment around them.
The phylogenetic ancestor of the modern day horse was no larger than a fox is today. It was a forest-dwelling animal. The scientific term for the little horse is Hyracotherium or the “Dawn Horse” to which it is sometimes referred. Scientists or paleozoologists have been able to trace the lineage of the horse much farther back than most other modern day animals.
Horses are from the Perissodactyla order of animals. They are odd-toed ungulates which means they have hoofed feet and an odd number of toes on each foot. They also have similar teeth structure and a mobile upper lip, like the rhinoceros and the tapir (a large mammal that is shaped like a pig with a short snout.) This indicated that they have common ancestors.
The horse originally began in the late Paleocene period in history. This was somewhere between 65.5 and 57 million years ago.
The small horse roamed in tropical forests. They had several toes spread fairly wide to accommodate the soft, moist soil of the forests. Over time, they would adapt to drier land. Their feet would slowly form only three toes with one large toe adapted to carry the frame of the larger animal the horse had become. The limbs of the horse grew longer and more streamlined. This allowed the horse to travel at a much faster speed. This speed was needed as their natural enemies also grew larger and faster.
The diet of the horse switched from tree and bush foliage to the grasses that had become more readily available. This would lead to larger and more durable teeth. The horse seemed to adapt more readily than some species. They changed more rapidly to fit their environment.
Fossils have been found throughout the world of all the various stages in horses’ development. Studying them has shown scientists just how adaptable the horse is. This would lead one to believe that the horse will be around for a long time to come.
In more modern times, the Spanish would introduce horses to the American continents. Some of these horses would escape and form large, wild herds.
Sources:
www.noanswersingensis.org
www.sciencedaily.com
