The United States Army accidentally set feral camels loose on the wild west in the 1800s. In 1836, U.S. Army Lieutenant George H. Crosman proposed establishing a camel corps to help transport supplies. In 19th century Australia, English settlers set out to explore the continent’s vast interior. But the hot, dry climate of the Outback was too harsh even for the most resilient horses.
So, settlers and traders enlisted the help of another domesticated animal that was up to the task: the camel. Thousands of camels were imported to Australia to work as pack animals on expeditions and trade routes. They continued to cross the continent until the early 20th century, when they were effectively put out of business by the arrival of the combustion engine. The camels were set loose in millions of square miles of arid desert where few animals could survive. Those camels didn’t just survive. They thrived! Today, that feral population numbers over one million!
Their broad feet help them:
- To help them walk on shifting sands.
- To store energy in fatty humps.
What happened to camels in North America?
Camels are associated with arid environments, especially hot environments. People are amazed to find out that camels originated about 45 million years ago in North America. They would have arrived in Eurasia via Bering Land Bridge which would have connected Alaska in Russia. Camels are famous for the adaptations that allowed them to flourish where most other large mammals would perish. But the fact is, camels didn’t originally evolve in the desert at all. They didn’t even evolve in Africa or Asia, where they live today. The story of the camel begins over 40 million years ago in North America and a rainforest.
The first known possible member of the camel family is Protylopus which appears in the fossil record about 45 million years ago. Protylopus was well suited to this environment because it was an artiodactyl, an even-toed, hoofed mammal whose members today include antelope, deer, and pigs. At the time, the flat-footed stance of the camel was assumed to be a primitive condition that other artiodactyls lost as they adapted to living in more open environments.
The suborder Tylopoda includes camels and their extinct relatives. It was named for the wide “cushion feet” that scientists thought all camels always had. But it turned out that the splayed toes that make modern camels so good at traversing the desert weren’t a feature that camels started with. They were a later adaptation. And Protylopus also didn’t have many other traits associate with members of the camel family, like long limbs and long, flexible necks.
Camel fossils in north America
The camel remains were discovered on west-central Ellesmere Island in the stretch cone and fewer areas. Now there are two fossil sites that paleontologists are working on there called the beaver pond site. Then about ten kilometers away, there’s the filed leaf bed site. And that’s where the camel was discovered. It took three field seasons to recover all of the bones. These are just fragments, and they all put together a part of a limb bone of a camel. Paleontologists have a couple of lines of evidence that indicate this is the camel.
- First, there’s collagen fingerprinting. This is work done by Mike Buckley at the University of Manchester using collagen fingerprinting. He could identify from the fragmentary remains that this animal was a camel.
In the field, these fossil fragments look just like shards. They could even be just fossil wood. They look a lot, in fact, like the easy wood that we’re also finding in the Strathcona fewer area. Strathcona fiord has a remarkable fossil record of the Pliocene age. So about three and a half million years ago, paleontologists have evidence of this time in the form of fossilized trees. So there’s a lot of fossilized wood. There are animals like a bear, a deer, and a camel.
Several traits seen in modern camels could have been very helpful for the high arctic camel. For example, the wide flat feet useful for walking on sand could also have helped snow. In addition, the hump serves as fat storage. So this could have been essential for an animal that would have to survive a long dark, cold winter. In addition, camels have huge eyes that could also be suitable for seeing in the low-light regime that would have characterized the winter in the boreal forest.
Protylopus is so strange that it’s sometimes put in a family with other, bizarre, not-quite-camel creatures, called the Oromeryicidae. Protylopus is still considered one of the earliest known Tylopods. It had many of that group’s more subtle. But it was defining traits, like having incisor teeth in the upper jaw and sharp, tusk-like teeth in the lower jaw. And speaking of its teeth, there’s one more thing about this very tiny camel. A closely related group of artiodactyls called ruminants have four-chambered stomachs that help them digest grasses. But Protylopus and its Descendents have had to make do with less efficient three-chambered guts.
So, Protylopus was more of a browser, preferring a diet of soft leaves and fruit over grass, which will play a big role in its evolutionary story. The little Protylopus didn’t make it out of the Eocene. But it had a cousin with whom it shared an ancestor. And it was better suited to the mosaic of forests and grasslands that was starting to transform North America. That cousin was the slightly larger Poebrotherium, which showed up about 37 million years ago.
- Poebrotherium had long, slender limbs, good for running on more open terrain, but like Protylopus, it still walked on hooves rather than toe pads.
- Fossils of Poebrotherium have been found across western North America, and in a greater range of habitats, from wooded grasslands to shortgrass prairies.
By its teeth specifically, we can tell its shorter molars that it still relied on leaves as its main food source rather than grass.
Poebrotherium disappeared from the fossil record about 33 million years ago. But other lineages continued to thrive as the shrubs and trees of the Oligocene turned into the grassy, open Miocene. It was the time of what you might call the Camelid Explosion!
- In the Miocene, camels reached their peak of diversity, when nearly 30 genera roamed all over North America.
In fact, camels at this time were so successful and abundant that they’re one of the most common herbivores found in Miocene fossil beds. This explosion in diversity saw the development of four different subfamilies, including the one that led to all modern camels: Camelinae. While these families had a lot of differences, they also had one major thing in common. They didn’t walk on tip-toes anymore.
For instance, fossils of the long-necked Aepycamelus have been found in deposits from this time, from California to Florida. In addition to its quite giraffe-like features and impressive height, this camel was notable. It’s one of the first to have feet like those of modern camels. While early camelids walked on the tips of their hooved toes, Aepycamelus walked on the padded bottoms of its feet.
It had relatively short toes, with ankle bones splayed out at the base, suggesting that its toes spread apart and were supported by large pads. And these new feet were a great adaptation for its new environment. Because Aepycamelus browsed on the open savanna, a lot like a modern giraffe does, where trees were fewer. So it had a lot of ground to cover in its search for food. But the way this camel looked and lived also brought about another innovation: It gave rise to a whole new way of walking.
- Aepycamelus was probably the first animal to develop the “pacing gait” seen in modern camels.
In a pacing gait, the front and back legs on the same side move simultaneously, rather than the front and back legs on opposite sides. It keeps those long legs from knocking into each other as the camel speeds up. That, in turn, allows for a longer stride that conserves energy. This is great when you have a lot of ground to cover. But the pacing gait also makes the animal a lot less stable, which is why most four-legged mammals don’t use it. It causes an awkward rocking motion as all the animal’s weight moves from one side to another.
It is where those wide, flat-toe pads came in handy. They helped stabilize the big, heavy camelids as they swayed from side to side, searching for their next meal. And as the Miocene went on, camels were getting bigger and heavier.
- Megatylopus was one of the biggest camels ever, at 3.5 meters tall – which is a meter and a half taller than most camels today.
Megatylopus is also one of the first camels that we’re pretty sure had that other famous camel feature: a hump. It had spines on the vertebrae just below its neck that were incredibly long, perfect for supporting a fatty, muscular lump of tissue. Those fat stores probably helped Megatylopus as it paced across the ever-expanding grasslands of North America.
- While Megatylopus wandered far and wide within North America, a close relative would be the first camel to leave the continent.
Sometime in the Miocene, Paracamelus crossed the Bering land bridge into Asia, changing camel history. The earliest fossils of this camel have been found in Nevada, dating back about 12 million years. By 7 million years ago, this intrepid explorer had already made it as far as Spain. Its fossils have been found throughout Europe and Asia, like China, Russia, Turkey, and Romania. Perhaps the strangest place it’s been found is on Ellesmere Island in northern Canada, where a 3.4 million-year-old fossil was reported in 2013.
That’s a strange place to find camel fossils because it’s very far north. So far north that, at 78.5 degrees latitude, it’s in the Arctic Circle. The Arctic was warmer 3 million years ago than it is today. If Paracamelus stayed in this environment year-round, it would still have lived in boreal forests with deep snow. Also, it experienced average annual temperatures below freezing and endured 6-month-long winters with little sunlight.
The very same adaptations that allowed Paracamelus to survive the unforgiving conditions of deserts and grasslands may also have been what allowed it. And other camels to possibly survive in the Arctic. For instance, their humps would have served them well during those long winters. Their large furry bodies would have retained heat longer. Their broad, padded feet that worked so well on sand could have functioned like snowshoes.
- Camelus, the genus of modern camels, was the first camelid to evolve outside of North America.
Its descendants are what is now known as the Old World Camels. They had to wait a few million years before their favorite travel companion hit the scene. Once humans and camels found each other, both animals would be changed forever. About 5,000 years ago, humans in Asia domesticated some species, Camelus bactrianus, the Bactrian camel. These are the double-humped camels that originated on the steppes of Central Asia. But there was a whole population of Bactrians that were never domesticated!
Fossils & DNA Records
DNA evidence has revealed that, by 700,000 years ago, the wild and domesticated Bactrians had diverged enough that they had become two completely distinct species. Today, only about 1400 wild Bactrians are still alive, the only genuinely wild members of the Camelus genus. At the same time that Bactrians were becoming domesticated in Asia. Another species, the Dromedarieswere also starting to be used by humans around: The Arabian Peninsula and the Horn of Africa.
Those dromedary camels are the species that were sent to Australia in the 1800s. But old-world camels aren’t the only members of the camelid family. They’re not the only ones that we domesticated. While ancient old-world camel relatives were roaming the Arctic 3 million years ago, another one traveled differently.
- Members of a genus known as Hemiauchenia left North America to check out South America, which had recently become connected by a land bridge.
Hemiauchenia likely became the direct ancestor of all of South America’s camelids. It includes the wild guanacos, which eventually gave rise to the llama. And the wild vicugna, from which alpacas are descended. So today, all modern members of the camelid family worldwide are either domesticated or have a domesticated descendant.
- That’s because all the features that made camels so good at adapting to harsh ecosystems their size, pacing gait, splayed toes. Their humps also made them useful companions to humans throughout the ages.
So, why do camels no longer roam their native turf of North America? In the second half of the Miocene, grasslands continued to expand, causing camels’ preferred leafy foods to become less common. While animals that were better adapted to feed on grass as horses flourished.
- One North American camel, called Camelops, lived just long enough to cross paths with humans when we arrived in North America.
Its remains have been found at a human hunting site dated to about 13,000 years ago. Soon after, though, Camelops vanished, and the time of camels in North America came to a close. But camels survived in their new homes on other continents. Once again began to spread to new frontiers with the help of human companions. So, camels have made an incredible journey, a journey that began in North America. They’ve adapted to some of the world’s most extreme environments, from the deserts of northern Africa to the Australian Outback.
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