Merychyus is an extinct genus of terrestrial herbivore of the family Merycoidodontidae (oreodont), endemic to North America during the Eocene-Miocene subepochs (35—4.9 mya) existing for approximately 29.667 million years. Merychyus was a cud-chewing plant-eater with a short face, tusk-like canine teeth, heavy body, long tail, short feet, and four-toed hooves.