Giant camels once roamed Canada's High Arctic - much further north than previously believed - and may have evolved their flat feet and humps as a result.
A Canadian Museum of Nature team has found 30 fossil fragments of a leg bone on Ellesmere Island, Nunavut, which have been dated to around three and a half million years ago, the mid-Pliocene Epoch. Other fossil finds at the site suggest that it was at the time a boreal-type forest environment.
"This is an important discovery because it provides the first evidence of camels living in the High Arctic region," says Dr. Natalia Rybczynski, a vertebrate paleontologist with the Canadian Museum of Nature.
"It extends the previous range of camels in North America northward by about 1,200 km, and suggests that the lineage that gave rise to modern camels may been originally adapted to living in an Arctic forest environment."
Some important physical characteristics suggested the fossil fragments were part of a large tibia, the main lower-leg bone in mammals, and that they belonged to the group of cloven-hoofed animals known as arteriodactyls, which includes cows, pigs and camels.
Digital files of each of the 30 bone fragments were produced using a 3D laser scanner, showing that they were from a very large mammal.
Full confirmation that the bones belonged to a camel came from a new technique called 'collagen fingerprinting'. Minute amounts of collagen, the dominant protein found in bone, were extracted from the fossils. Using chemical markers for the peptides that make up the collagen, a collagen profile for the fossil bones was developed and compared with those of 37 modern mammal species, as well as that of a fossil camel found in the Yukon.
The collagen profile for the High Arctic camel most closely matched those of modern camels, specifically dromedaries - camels with one hump - as well as the Yukon giant camel, which is thought to be Paracamelus, the ancestor of modern camels.
"We now have a new fossil record to better understand camel evolution, since our research shows that the Paracamelus lineage inhabitated northern North America for millions of years, and the simplest explanation for this pattern would be that Paracamelus originated there," says Rybczynski.
"So perhaps some specializations seen in modern camels, such as their wide flat feet, large eyes and humps for fat may be adaptations derived from living in a polar environment."