The carcass of an extinct steppe bison, discovered two years ago melting out of a cliff in a remote village in the Northwest Territories, is shedding new light on the Ice Age species - and could rewrite the history of human migration in Canada as glaciers began retreating in the region nearly 14,000 years ago. An analysis showed the specimen was one of the last of its kind in ancient Beringia - the ice-free, northwest corner of the continent that was once linked to eastern Siberia. But the rare find, documented by a team of Canadian, British and American scientists in the latest edition of the journal Quaternary Science Reviews, has wider implications for dating the retreat of the glaciers in northern Canada and the possible entry of human hunters from Asia - the ancestors of today's aboriginal Canadians - into the continental interior.
     The 'partially mummified' steppe bison was found two years ago in Tsiigehtchic, N.W.T. The animal's distinctive skull and wide horns were largely intact, but more tantalizing were portions of preserved limbs, hide and intestines - that permitted detailed genetic analysis allowing scientists to accurately situate the specimen in the evolutionary history of North America's bison populations. "Based on the genetics, this animal was one of the last of the remaining steppe bison in Beringia," Yukon government paleontologist Grant Zazula said. "Shortly after this, populations in the North are completely replaced by bison that evolved in the mid-continent."
     What the find also shows is that the post-glacial ecosystem inhabited by the steppe bison must have supported large mammals earlier than previously known. That, say the scientists, suggests human hunters may well have entered the area around this time and - potentially - left traces of their own activities at sites still waiting to be found by archeologists. "Given that steppe bison inhabited the northern portal to the 'ice-free corridor,' data from the Tsiigehtchic bison raises the potential for discovery of archaeological sites in the lower Mackenzie River Valley," the study states.

Sources: Canwest News Service, Calgary Herald (27 October 2009)