FURTHER doubt has been cast on the idea that human hunters suddenly wiped out many of the world鈥檚 species of large mammal at the end of the last ice age. Some, including mammoths, musk oxen and horses, seem to have bounced back after disappearing from much of Siberia for more than a millennium.
Carbon-dating of preserved bones shows that many species vanished from Siberia about 11,000 years ago. Some, such as the woolly rhinoceros, left no later remains, but others reappeared almost simultaneously more than a thousand years later, Ross MacPhee of the American Museum of Natural History in New York told the conference. On their return, musk oxen survived in Siberia for a few thousand years, and mammoths lasted on Wrangel Island in the Arctic Ocean 鈥� although in dwarf form 鈥� until about 4000 years ago.
Last month a study by Anthony Stuart of University College London reported that the giant deer known as Irish elk vanished in most of Europe 11,000 years ago, only to reappear a couple of thousand years later in Siberia, where they survived for about 1200 years (Nature, vol 431, p 684).
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DNA studies support this idea, says MacPhee, suggesting that some species which survive to this day, such as musk oxen, went through a population bottleneck from which only a few individuals survived. He believes these survivors lived in pockets, isolated from whatever caused the rest of the population to crash.
鈥淪urvivors, such as musk oxen, lived in pockets, isolated from whatever caused the rest of the population to crash鈥�
Changing climate has also been proposed as a cause of the large mammals鈥� demise.
