The sight of a camel immediately brings to mind the vast, sandy deserts of Africa and Asia, or perhaps the high Andes mountains where their smaller relatives, the llamas and alpacas, roam. Despite this global distribution, the true origin of the entire Camelidae family is much closer to home than most people realize. The lineage that gave rise to all modern camels, from the dromedary to the vicuña, began its evolutionary journey in North America. This continent served as the evolutionary engine for the camel family for tens of millions of years, making the camel one of North America’s most successful exports.
The North American Birthplace of Camelidae
The Camelidae family originated and first diversified in North America approximately 44 to 46 million years ago, during the Eocene Epoch. This foundational period saw the emergence of the first camel-like creatures in environments that were often subtropical, such as in what is now South Dakota. For the next 40 million years, North America was the sole domain of the camelids, where they underwent extensive evolutionary radiation.
This ancient family evolved into two major branches that persist today. The Old World camelids include the two-humped Bactrian camel and the one-humped dromedary. The New World camelids, known as lamoids, encompass the llama, alpaca, guanaco, and vicuña. Fossils discovered across the continent provide a complete record, demonstrating that the entire evolutionary blueprint for both groups was established and refined here.
Tracing the Ancestral Lineage
The earliest known ancestor was the tiny Protylopus, which lived around 40 to 50 million years ago and was no larger than a rabbit. This primitive creature quickly gave way to slightly larger forms, such as Poebrotherium, which emerged about 35 million years ago and reached the size of a goat. Poebrotherium had already developed traits similar to modern llamas and camels.
The lineage continued to diversify, producing a wide array of forms, including the delicate, gazelle-like Stenomylus and the peculiar, long-necked Aepycamelus. A major evolutionary divergence occurred between 16 and 17.5 million years ago, when the two modern tribes, Camelini and Lamini, split within North America. Later, the continent hosted giant species like Titanotylopus, which could stand up to 12 feet tall at the shoulder. The last North American camel genus was Camelops, a large animal that roamed widely across the western part of the continent.
The Great Migration Across Beringia
The modern global distribution of camels resulted from two major dispersal events. The first migration, leading to the Old World camels, took place during the late Miocene, approximately 6 to 7.5 million years ago. Ancestral forms, specifically the genus Paracamelus, utilized the Bering Land Bridge, or Beringia, which periodically connected Alaska and Siberia during periods of lowered sea level.
These migrating camels crossed into Asia, where they continued to evolve and spread across the continent, eventually giving rise to the modern Bactrian and dromedary camels found in Eurasia and Africa. Simultaneously, members of the Lamini tribe began a journey south. The ancestors of the New World camelids migrated into South America during the Pleistocene Epoch, between 3 and 1 million years ago.
This southern movement was made possible by the formation of the Isthmus of Panama, which linked the two American continents, allowing for an extensive faunal exchange. The descendants of these southern migrants established themselves in the Andes region, evolving into the four species of lamoids: the llama, alpaca, guanaco, and vicuña.
Why Camels Vanished from North America
Despite being their evolutionary center for millions of years, North America lost its native camelids during the late Pleistocene extinction event, approximately 10,000 to 13,000 years ago. The last surviving species, Camelops hesternus, vanished alongside many other large North American mammals, including mammoths and saber-toothed cats.
The disappearance is attributed to a combination of rapid climate change and the arrival of human hunters on the continent. As the climate shifted toward the end of the Ice Age, habitats changed, affecting the vegetation and food sources upon which the camels depended. Evidence shows that early human populations did hunt Camelops, suggesting that hunting pressure contributed to the decline of the already stressed populations. Once Camelops died out, the camel family was gone from its continent of origin.