March 5, 2013 at 11:15 AM ET
The ancestors of the modern camel included an Arctic giant that lived in chilly coniferous forests about 3.5 million years ago. The ancient ungulates were 30 percent bigger than living camels today, weighing about a ton.
Scientists pieced together a picture of this camel from a crop of 30 fossilized bone fragments found on Ellesmere Island in the Canadian Arctic. It's the first evidence that camel ancestors lived so far north. The location and age of the bone fragments indicate that the camel lived at time when the planet was 5.4 degrees Fahrenheit (3 degrees Celsius) warmer than it is today, when parts of the Arctic were covered in coniferous forests filled with larch and birch. The Ellesmere Island region itself was about 36 degrees F (20 degrees C) warmer than it is today.
"Being big was something camels did very well," Natalia Rybczynski, a research scientist at the Canadian Museum of Nature told NBC News. "An animal today that would be an analogue is the moose — it's huge," she added. A large body size would have allowed it to regulate its body temperature better during the winters and cover larger distances walking, she explained. Rybczynski and her collaborators described the fossil and its analysis in a paper published Tuesday in Nature Communications.
Today's living camels have broad, flat feet, to help them walk on sand. Those feet could have evolved in an Arctic camel to walk on snow, Rybczynski says. And the ability to pack away fat, as the modern camel does in its hump, could have been useful to an Arctic camel that needed to survive dark, snowy winters that were six months long.
Rybczynski found the first fragment of the specimen in 2006. Over later visits in 2006, 2008 and 2010, she and her collaborators assembled a collection of 30 bone fragments that fit together to resemble the tibia of a large ungulate. A closer analysis of the structure of the bone hinted that they had a large cud chewer on their hands.
For further proof, the team extracted collagen, a protein, from the fossils. Frozen in the Arctic mud, the biological molecule was preserved exceptionally well, and it survived better than ancient DNA would have fared. "It's mummified," Rybczynski said. Collagen isn't as information-rich as DNA, but has enough of a chemical fingerprint to show which family of animals the fragments came from. The ancient northern camel is related to today's dromedary, and to another now-extinct camel relative called the Yukon camel.
The high Arctic camel's fossil traces suggest that weird adaptations found in the modern camel may have arisen to fill a different need in its ancestors, and serve as a historical example of a species that lived on a planet that was warmer than it is today. That's what makes the fossil hunt fun fo Rybczynski. "You can pick up these tiny fragments that are that big, that makes these connections," she says.