英语听力：探索发现 2012-09-14 长毛象王国 Mammoth—3（在线收听）

 The Yukon and its neighbor, modern-day Alaska, were once part of the land that was Beringia. Stunning though this region is today is just a shadow of the world that was encountered by the First Americans. Underground, the soil is frozen solid, as it has been ever since the Ice Age. Locked within this permafrost are vital clues to help us to recreate the ancient wildlife of Beringia. Even today, Alaska’s rivers wash intriguing traces of the past out of permanent frost. So who did this titanic tusk belong to? Beringia’s largest resident, the woolly mammoth. Weighing six tons or more, the woolly mammoth was about the size of a bull African elephant today. And it had equally impressive ice age neighbors, some of which survive here almost unchanged, and some of which can still be found elsewhere. Although 14,000 years is long enough to see enormous climate changes, in revolutionary terms, it’s just the blink of an eye. Beringia was a world with familiar North American animals lived alongside prehistoric giants.