纪录片《我们的地球》 第05期 从南极到北极（5）（在线收听）

Northern Canada's wild frontier.

这里是加拿大北部荒野

Here nature stages one of her greatest dramas.

大自然正在此上演着一幕最壮观的演出

Every year three million caribou migrate across the Arctic tundra.

每年，300万迁徙的北美驯鹿都将穿越北极苔原

The immensity of the herd can only be properly appreciated from the air.

庞大的鹿群只有在空中才能完全领略它的壮观

Some herds travel over 2,000 miles a year in search of fresh pastures.

有的鹿群一年得走上2000多英里，才能到达新鲜草场

This is the longest overland migration made by any animal. They're constantly on the move.

这是动物界中最长的陆地迁徙。它们总是不停地赶路

Newborn calves have to be up and running the day they are born.

新生的小鹿必须在出生的第一天就站起来奔跑

But the vast herds do not travel alone.

但是庞大的鹿群并非独自旅行