Dromedaries may be well suited to survive scorching deserts, but new evidence suggests that some of their physical traits may have evolved millions of years ago as adaptations to a much cooler climate thousands of kilometres away — in what is today the Canadian Arctic.
The discovery of High Arctic camel fossils on the west coast of Ellesmere Island, Nunavut, by a team from the Canadian Museum of Nature, in Ottawa, adds to the evolutionary story of the modern camel. Scientists have long believed that the Camelidae family, which includes llamas and camels, originated in North America and migrated across the Bering Strait to Asia and Africa, but this find suggests that the direct ancestors of modern camels lived much farther north than previously thought.
“We tend to think that the traits we see in an animal were adapted for the conditions we see them in today,” says Natalia Rybczynski, the paleobiologist who led the team. “The hump becomes interesting when you think of it as a trait that could be useful in a High Arctic environment.”
The camels’ fat-storing humps would have helped them endure the harsh winters, and their wide, padded feet, which are useful on sand, would have aided them in walking on snow or across wetlands. Camels are also known for their ability to see in the dark, a skill that could have evolved for the dark Arctic winters.
Rybczynski and her team unearthed the first fossils of the then unknown animal in the summer of 2006. She quickly realized that the remnants belonged to a creature larger than any other she’d found on previous digs in the region, which have uncovered horses, bears and a walking seal-like animal called Puijila darwini.
Over the next few summers, more of the unknown fossils emerged. But it wasn’t until late 2010 that the team could be certain of what it had discovered. Unlike most fossils, which are petrified, the fragments Rybczynski found still contained collagen, a protein that the Arctic’s cold temperatures helped preserve. Through a process known as collagen fingerprinting, it was determined that the animal’s closest relative is the dromedary, the single-humped Arabian camel. The team’s research was published in the online journal Nature Communications in March.
Rybczynski estimates that the animal was about 30 percent bigger than today’s camel, with an average shoulder height of 2.7 metres, making it the largest land mammal found in the High Arctic to date. It lived roughly 3.5 million years ago during the Pliocene epoch, just before the onset of an ice age, in an Arctic far different than the one we know today. At that time, what now forms Ellesmere Island had a mean annual temperature of 0°C — about 14 to 22 degrees warmer than the current average temperatures — and was covered with a boreal-type forest. “The conditions in the High Arctic are pretty extreme,” says Rybczynski. “This is a place where adaptations would tend to evolve.”
Image gallery of the researchers at work on Canada’s stunning northernmost island.