Evolution of the Horse, Equus caballusFamily: EquidaeEquus caballus
There is only one surviving prehistoric horse, it is the Przewalski Horse and is the oldest breed of horse today!
Horse history can be traced back to a prehistoric animal known as the Candylarth. The Candylarth was about the size of a medium-sized dog and they had five toes on each foot and thickened nails. These extinct animals were ancestors to not only the horses, but to all hoofed animals.
The evolution of the horse itself can be traced to an animal known as the Eohippus, which lived about 60 million years ago. it had teeth designed for eating shrubs rather than grass. Over time this animal evolved, getting bigger and began to eat grass. And finally, during the Ice Age, the first true primative horse came into existence.
The modern horse is the direct descendant of the Eohippus. They lived in the Americas, Europe, and Asia continents. At that time there were land bridges connecting these continents. The first true horses traveled freely between the continents until these connecting bridges receded. Eventually the horse became extinct in America for thousands of years until man reintroduced it.
The Eohippus had four toes on each forefoot and three on each hind foot, with each toe ending in a small hoof. The food had a pad in the center, much like that of a dog that carried most of the animal's weight. This pad has become the small growth on the back of the fetlock called the ergot on the modern horse. The Eohippus also had teeth meant for eating shrubs not for grazing on grass.
The primitive horse continued to evolve and adapt to the environment. Horses became larger and began to eat grass as the climate became drier. The central toe began to bear most of the animal's weight and the outside toes diminished in size and function.
The first true horse came into existence during the Ice Age and was about the size of a small pony. Primitive horses could still travel freely between the continents until the land bridge across the Bering Strait disappeared around 9000 BC, isolating the Americas from Europe and Asia. Around 8,000 years ago horses became extinct in America and would not be reintroduced until the 16th century with the arrival of Cortez in Mexico.
The horses in Europe and Asia evolved to survive well in different climates. By the end of the Ice Age, there were four types of primitive horses:
- Forest Horse Equus caballus silvaticus:
The large Forest Horse, also known as the Diluvial, existed in Scandinavia nearly 10,000 years ago and was being domesticated around 3,000 years ago. This primitive horse was a heavy sturdy horse with large feet, and a thick coarse coat.
- Przewalski's Asiatic Wild Horse Equus caballus Przewalskii Przewalskii Poliakov:
The Asiatic Wild Horse or Przewalski Horse, is the only surviving prehistoric horse. These horses were rediscovered in Central Asia by the Russian explorer Przewalski and cataloged in 1881 by the zoologist J.S. Poliakov. They are fairly short (12-14 hands), generally dun-colored, have a dorsal stripe, and sometimes leg stripes. The Przewalski Horse is believed to be the ancestor of the Arabian and other Eastern horses.
- Tarpan Equus caballus gmelini:
The Tarpan was found in desert climates, and lived in southern Russia. Because these wild stallions often attacked and killed domesticated stallions, these horses were hunted. By the late 19th century, most of the wild Tarpans had been killed. They had been interbred with domesticated stock so their bloodlines did not disappear, but the wild, true version did. They are similar in size and appearance to the Asiatic Wild Horse with a brown color, dorsal stripe, and black mane and tail. It is thought that the Asiatic Wild Horse and the Tarpan are the ancestors of the modern warmblood breeds (mix of heavy horse and Thoroughbred).
- Tundra Horse:
The Tundra Horse originated in northeastern Siberia, where remains of this horse have been discovered in the valley of Yuma. It is speculated that this primitive horse may have been the ancestor to the small Yakut ponies, but is not believed to have influenced the development of other modern horse breeds
Modern horses come in a variety of colors and vary greatly in height and size. The miniature horses are around 34 inches in height and the heavy horses can be up to 72 inches tall measured at the withers. They move on four legs and generally have four gaits: walk, trot, canter, and gallop, but some so-called ‘gaited' horses such as the American Saddlebred and the Tennessee Walking Horse have three or five gaits. They have a mane along the top of the neck and a long, flowing tail.