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Mammoths Didn't Go Out with a Bang
from Nature News
Why are there no more woolly mammoths? The last isolated island populations of these huge beasts disappeared about 4,000 years ago--well after the Pleistocene extinction that wiped out much of the world's megafauna--but what triggered their demise remains a frustrating mystery. According to the latest study to contribute to the ongoing debate, the last mammoths disappeared after a long, slow decline in numbers rather than because of a single cause.
Woolly mammoths (Mammuthus primigenius) once roamed over cold, dry grasslands in the Northern Hemisphere called mammoth steppe. Their remains are especially common in Beringia, the bridge of land that connects eastern Russia and western Alaska. Now, palaeoecologist Glen MacDonald at the University of California, Los Angeles, and his colleagues have tracked the pattern of the Beringian mammoth's extinction. Their results are published today in Nature Communications.
MacDonald and his colleagues combined a geographical database of mammoth finds with radiocarbon dates for mammoth specimens, prehistoric plants and archaeological sites to follow how woolly mammoth ranges expanded and contracted during the past 45,000 years.
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