Pleistocene Ice Ages

These basic shapes of mountain ranges and river basins were then refined by a series of ice ages, the Pleistocene (2 million to 10,000 years ago). Where ice covered the land there were obviously no ecosystems, but in between periods of glaciation were periods of temperate climates. As each ice age receded, ecosystems advanced from the south and east. We know little about these ecosystems, however, because of the geological ravages of the glaciers during ice ages, and the rapid erosion between glacial advances, which left few fossil records intact. Of course, the species here now, such as mountain goat, elk, deer, moose and bighorn sheep, were present, but others, now extinct or no longer living in the Basin, were here also. Two glacial deposits in the Okanagan suggest what it was like in the Columbia Basin at that time (Harington, in Ludvigsen, 1996): at Westwold, there were small horses and bison, in addition to fishes and small mammals. Near Lumby were fossils of those species, as well as a Columbian mammoth. In north-central British Columbia also lived a giant bison; since this species also lived on the Canadian prairies and Idaho, it must have lived also in the Columbia Basin. Most surprising was a giant, ground-dwelling sloth of South American ancestry, unearthed at Quesnel. It became extinct 9,000 years ago. Other extinct, ice-age fauna, like the giant mastodon, the gigantic imperial mammoth, the cave bear, dire wolf, saber-toothed cat and an extinct helmeted muskox, found on the coast and elsewhere in western Canada, likely lived here as well.