From
WikipediaEvolution
The earliest known camel, called Protylopus, lived in North America 40 to 50 million years ago (during the Eocene).[20] It was about the size of a rabbit and lived in the open woodlands of what is now South Dakota.[65][66] By 35 million years ago, the Poebrotherium was the size of a goat and had many more traits similar to camels and llamas.[67][68] The hoofed Stenomylus, which walked on the tips of its toes, also existed around this time, and the long-necked Aepycamelus evolved in the Miocene.[69]
The direct ancestor of all modern camels, Paracamelus, existed in the upper Miocene to Middle Pleistocene.[70][71] Around 3–5 million years ago, the North American Camelidae spread to South America as part of the Great American Interchange via the newly formed Isthmus of Panama, where they gave rise to guanacos and related animals, and to Asia via the Bering land bridge.[20][65][66] Surprising finds of fossil Paracamelus on Ellesmere Island beginning in 2006 in the high Canadian Arctic indicate the dromedary is descended from a larger, boreal browser whose hump may have evolved as an adaptation in a cold climate.[72][73] This creature is estimated to have stood around nine feet (2.7 metres) tall.[74]
The last camel native to North America was Camelops hesternus, which vanished along with horses, short-faced bears, mammoths and mastodons, ground sloths, sabertooth cats, and many other megafauna, coinciding with the migration of humans from Asia.[75][76]