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Idaho SuperGraphic

America's first horse

Horses lie at the heart of one of North America's greatest mysteries. The horse is believed to have originated in North America just before the Eocene Epoch, 57.5 million years ago. Ancestors of the modern-day horse continued evolving here until about 11,000 years ago when the mass extinction of megafauna (large or relatively large animals of a particular region or time period) occurred, taking the horse with it. However, before mass extinction swept the land, some ancestors of the horse had migrated northwest across the Bering Land Bridge, a connection between Alaska and Siberia to Eurasia. The horses were able to do this during a time of lower sea levels. Horses completely disappeared from North America for more than 11,000 years. It was the Spanish conquistadors who brought them back from Europe to the new world via sailing ships, reintroducing them to North America and using them for transportation and beasts of burden in the late 1500s. Over the years, some horses escaped, were released or given to the Native Americans, and some were stolen. But before long, horses were again roaming the grasslands of North America. Pioneers who traveled along the famous Oregon Trail noted bones on the west side of Idaho's Snake River, across from the present town of Hagerman. They probably never thought that the animals that left them might have been the ancestors of their modern-day horses. The Hagerman Horse existed during the Pliocene Epoch, which ranged from 1 to 12 million years ago, and is the oldest- known representative of Equus simplicidens, the genus that includes all modern horses, donkeys and zebras.

Related images

Illustration of a zebra-like horse with stripes
The Hagerman Horse. Courtesy of the National Park Service.

The discovery A horse is a horse... Unless of course