听力文本

Walruses are now gathering on low-lying islands.
海象正往低岛聚集。
They gave birth on the sea ice, but with this platform now gone,
它们在海冰上产仔，但这块平台已经消失，
they need a new place to haul out and nurse their young.
它们需要新的地方哺育幼仔。
After several days at sea, the male bear finally makes landfall,
在海上漂流了几天之后公熊终于登陆了，
drawn by the pungent smells emanating from the island.
它已经嗅到了岛屿上散发出的强烈气味。
By the end of the summer, the bear has lost half his weight.
但在夏天结束时,公熊的体重已经减少了一半。

With the ice long gone, he is forced onto land in search of food.
冰层早已融化,迫使它到陆地上寻找食物。
There will be no easy meals on this island.
在这座岛上找到吃的并不容易。
Walruses are the largest seals in the world.
海象是世界上最大的海豹科动物。
They weigh over a ton and are armed with tusks a metre long.
体重超过1吨，有长达1米的象牙为武器。
Exhausted from his swim, the bear must regain his strength.
游得精疲力竭的北极熊必须恢复体力。
The next day, a sea fog shrouds the island.
第二天海雾笼罩了这座岛屿。
The walruses sense that they are in danger.
海象已经意识到危险。

视频及简介

地球的南北极分别是南极洲和北冰洋，它们几乎长年都是冰天雪地。春去秋来，太阳直射点发生迁移的时候，这两个冰封的世界随之发生最极端的季节变化，从极地冬天的黑暗和严寒转变到极地夏天的午夜和光明，太阳全天24小时不落。