By Sid Perkins
The long-lost cousins of today’s camels once roamed the high Arctic, browsing open forests in regions that are near-barren landscapes today. That’s the conclusion from an analysis of the fragmentary remains of an ancient leg bone unearthed on Canada’s Ellesmere Island, which lies just west of northern Greenland. The find also adds to the tantalizing clues about how these moose-sized, presumably shaggy progenitors fit into the camel family tree-a lineage that today boasts only two species of true camels but includes plenty of South American relatives such as llamas, alpacas, guanacos, and vicunas.
Today, camels inhabit arid regions stretching from northern Africa to the interior of Asia. But ancestors of the creatures first evolved in North America about 45 million years ago, says Natalia Rybczynski, a paleontologist at the Canadian Museum of Nature in Ottawa. Some of these animals crossed a land bridge from what is today Alaska to eastern Siberia-and that meant they were living, even thriving, at latitudes where few mammals can now subsist.
The fossils, dug up by Rybczynski and her colleagues in recent field seasons, came from a gravel-rich layer of sediments laid down more than 3.4 million years ago. The 30 or so bits of bone, none more than 7 centimeters long, have suffered much since they were entombed: Ice sheets have scoured Ellesmere Island several times in the past few million years, and today’s freeze-thaw cycles continue to splinter fossils into ever-smaller fragments, Rybczynski says. The sizes and shapes of the bone bits suggest that they came from a tibia (a lower leg bone), but from those clues alone it’s impossible to identify the species or group of mammal the fossils came from. However, some bone features clearly indicate that the creature was an artiodactyl, a broad group that today includes deer, cows, and camels.