英语听力:探索发现 2012-10-07 长毛象王国 Mammoth—13(在线收听) |
Small ears also help to minimize heat loss, the opposite effect of those huge heat-dispersing ears of their relatives, African elephants. Other Beringia animals have more than a fur coat to help them cope with cold. This skull belongs to the bizarre-looking saiga antelope, one of the less familiar faces of the ice age scene. Like the musk ox, saiga have a thick winter coat of hollow hairs for extra insulation. But they have another adaptation all of their own, an enormous bulbous nose. The nose is shaped like this because it contains large air sacs which pre-warm cold air while breathing in and retain precious moisture before breathing out. So saiga, too, were well-equipped to live in the cold, dry climate of Beringia. Today they’re only found in another bleak environment, the steppes of central Asia.
Some ice age animals took a totally different approach to surviving the winter. Arctic ground squirrels feed up in autumn, building up as much body fat as possible, and almost doubling their weight. As the first snows fall, they retreat to their underground burrows and bypass the winter entirely. |
原文地址:http://www.tingroom.com/lesson/yytltsfx/2012/244838.html |