IUCN / SSC Cat Specialist Group - Digital Cat Library |
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| Guthrie, R.D.; Guthrie, M.L. | |
| On the Mammoth's dusty trail | |
| 1990 Natural History (7/90): 34-41 | |
Frozen fossils yield a detailed picture of a vast northern grassland and diverse animal community that flourished during the Ice Age. Yet there was another side to the Ice Age cold. Above the huge North American ice sheet, woolly mammoths, bison, and horses lived on an arid grassland in the unglaciated Yukon and Alaska. Lions roared in the white night above the Arctic Circle, and camels and horses fed on the North Slope of Alaska's Brooks Range. This land at the back of the north wind, which we call the Mammoth Steppe, waxed and waned with the glaciers throughout the Pleistocene. As the oceans ebbed, Alaska was joined with Asia across a broad front of exposed continental shelf. Among the most common large mammal fossils found in Siberia and Alaska are the bones of the massive, ruggedly built steppe bison, closely related to bison that once roamed the American plains. Steppe bison, however, had humps situated farther back behind the shoulder blades, carried their heads higher, and had a smaller forehead hair "bonnet" than present-day bison, relying on much thicker facial skin for protection from the sharp horn tips of rivals. By the late Pleistocene, some 400,000 years ago, these bison spread out over the entire Mammoth Steppe, displacing several species of muskoxen, which then became extinct. Numerous other large mammals roamed the Mammoth Steppe: woolly rhinos, saiga antelopes, ibex, reindeer, camels, giant bears, two species of muskoxen, wapiti, giant deer, saber toothed cats, hyenas, sheep, wolves, cheetahs. Some species were only locally abundant, while others ranged across the entire steppe. More than two dozen frozen partial mummies of Mammoth Steppe mammals have been found in Siberia and Alaska. The most famous of these are the remarkably well preserved Siberian Beresovka mammoth, an adult excavated in 1901, and the Dima mammoth, a complete carcass of a six-to-seven month old baby discovered in 1977. Frozen fauna and other Ice Age fossils give us a unique perspective on the possible results of global warming. The extremes of the Mammoth Steppe were apparently brought about by a shift of only a few degrees in average temperatures and a slight change in annual rainfall. Seasonal shifts in weather, maintained long enough can alter vegetation profoundly, reorganizing landscapes over much of the globe. |
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