How Camels Evolved Their Humps — In Northern Canada

Camels aren't typically associated with northern climates, but a recent discovery of 3.5 million-year-old fossils by Canadian paleontologist Natalia Rybczynski suggests that this is precisely where they came from. The finding was made on Nunavut's Ellesmere Island, the most northerly part of Canada, and an area that was much more temperate back during the mid-Pliocene era. But it was cold enough, say the researchers, to help the camels evolve their humps — an adaptation that would eventually prove useful in a vastly different ecological context.

Analysis of the bones show that the giant camel is likely a distant relative of the modern dromedary camel, the species known for its one hump. And as its name suggests, the giant camel was a rather large beast. Looking at the fossil evidence, Rybczynski and her team figure it was about 9 feet (2.7 meters) tall at the shoulder, which is 30% larger than today's camels. And it weighed close to 2,000 pounds (900 kg).

How Camels Evolved Their Humps — In Northern Canada

Millions of years ago, Ellsmere Island featured a boreal forest with temperatures ranging anywhere from 57 to 72 degrees Fahrenheit (14 to 22 Celsius). It was a warm period that predated the onset of the Quaternary glaciations. There was plenty for the camels to eat back then, including lots of grass and leaves. Today, camels are regarded a desert dwelling animals, but during the mid-Pliocene they browsed through the Arctic forests.

And fascinatingly, Rybczynski theorizes that the hump was already an important characteristic of the camel even back then. In her study, she writes:

Their iconic hump(s), containing fat, also may have been adaptive. As seen in high-latitude ungulates today, fat deposits could have been critically important for allowing populations to survive and reproduce in harsh climates characterized by 6-month long, cold, winters.

Indeed, given just how far up north they were, the winters would have been long and harsh — lasting for half the year and featuring 24 hours of darkness. These camels, in order to survive, would have likely shed most of their weight while feeding off their hump's fat reserves.

The camel populations eventually dispersed across the Bering Strait during the cold winters by using Arctic sea ice, where they resettled in Asia and adapted to an entirely different kind of life.

You can read the entire study at Nature.