Protoceras is an extinct genus of Artiodactyla, of the family Protoceratidae, endemic to North America from the Oligocene through Miocene epochs existing for approximately 13 million years. Like so many ancient even-toed ungulates, Protoceras have proven difficult to classify. Their closest living relatives are most likely camels rather than elks or pronghorns. Protoceras was one of the earliest members of this distinctive group of megafauna mammals, with four-toed feet (later protoceratids only had two toes) and, on the males, three sets of paired, stubby horns running from the top of the head down to the snout. Illustration originally captioned: Oligocene deer, Protoceras Celer, after Scott. American Museum of Natural History. No date.