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When did Equus evolve in North America?
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Standardbred gelding with dark bay coat.
The genus Equusāwhich includes modern horses, asses, and zebrasāevolved in North America approximately 4 million to 4.5 million years ago during the Pliocene Epoch.1
It descended from the genus Pliohippus and proved to be an extremely successful lineage, spreading from North American plains to South America and the Old World by the early Pleistocene. Although Equus flourished in North America for a significant period, it disappeared from the continent between 10,000 and 8,000 years ago, only to be reintroduced by Spanish explorers in the 16th century.1