An illustration of the extinct Arctic camels. Credit: Julius Csotonyi

New Delhi, March 6: What Natalia Rybczynski first thought were pieces of wood on an Arctic island have turned out to be fossilised bone fragments that may change current ideas about the evolutionary history of the world’s camels.

Rybczynski, a Canadian palaeobiologist, and her colleagues have discovered evidence for extinct giant camels in the Arctic about 3.5 million years ago that may have been the remote ancestors of modern camels that roam deserts worldwide.

The researchers have found 30 fragments of what appear to be the fossilised bones of an ancient large camel on Canada’s Ellesmere island during three summer expeditions between 2006 and 2010. Their findings, reported yesterday in the journal Nature Communications, suggest that camels with thick hair and 30 per cent larger than modern camels with an average shoulder height of 2.7 metres once lived far north of the Arctic circle.

The discovery may offer an alternative explanation for camels’ humps. The researchers speculate that the humps — which store fat — may have been an adaptation to survive the extreme low Arctic temperatures and four months of near-complete darkness.

Natalia Rybczynski collects a fossil on Ellesmere island in 2008. Credit: Mark Lipman, Canadian Museum of Nature

“It would be a big surprise — we’ve been assuming camels are so perfectly adapted for the desert, but it’s possible that the humps evolved as an adaptation to a completely different environment,” Rybczynski told The Telegraph in a telephone interview.

Modern camels are primarily found across stretches of arid land from northern Africa to India’s Thar desert to Mongolia, and their nearest living relatives are the llamas, alpacas and vicunas of South America.

Evolutionary biologists believe that camels originated about 45 million years ago in North America, and had dispersed into Eurasia by seven million years ago using the Bering land bridge that joined present-day Alaska to Russia. While earlier studies have revealed fossils of another Arctic camel called the Yukon camel, Ellesmere island is more than 1,200km north and 2,000km away from the Yukon fossil sites.

The first bone Rybczynski found in 2006 looked like a piece of fossilised wood, but on more detailed examination appeared like a bone. Over three other summer expeditions to the site, she found 29 more fragments that appeared to be part of a leg bone of a camel.

A technique called collagen fingerprinting developed by collaborator Mike Buckley at the University of Manchester in the UK provided the strongest evidence to suggest that the bone fragments in Ellesmere island belonged to a camel.

“The collagen fingerprinting studies suggest that this camel was close to the dromedary,” said Rybczynski, a scientist at the Canadian Museum of Nature in Ottawa, who led the field expeditions. Dromedaries are modern-day single-humped camels.

The age of the fossils — about 3.4 million years old —was determined by John Gosse at the University of Dalhousie in Canada. He analysed the abundance of rare radioactive elements in minerals found in the sediments where the fossils were embedded to assign the dates.

Camel biology researchers say the fossils highlight the high adaptability of camels through history. “Camels can tolerate temperatures above 40 degrees and up to minus 40 degrees,” said Nitin Patil, director of the National Research Centre on Camel, Bikaner.

The NRCC estimates that India has about 5,40,000 camels — three dromedary breeds in Rajasthan, one in Gujarat, and double-humped bactrian camels in Ladakh. “We’re trying to understand their adaptability through molecular biology,” Patil who was not associated with the Canadian study told this newspaper.

Rybczynski and her colleagues believe the Arctic camel lived in a forest environment, during a period when the global temperatures were about two to three degrees higher than current average temperatures. They speculate that the Arctic camel would feed on the trees of the forests, and depend on woody material during the long winters.

The scientists believe they were lucky the Arctic cold helped preserve collagen, the main protein found in bones. Rybczynski said the collagen analysis allowed them to generate profiles of its proteins which — like fingerprints — can be used to distinguish between mammals.