They're born to move, to move or die, forging ahead against terrifying odds, navigating the first of millions of miles, spanning continents on fledgling wings, clattering ever onwards.

他们天生就要迁徙，不迁徙即是选择了死亡。与可怕的对手周旋，它们一次要走数百万英里，羽翼未丰的翅膀振翅而飞跨越大洲。

Right now, our planet is on the march, on the wing, on the run, and these are the tales of its creatures, born into the most moving stories on earth, the stories of the great migrations.

现在，我们的星球也在迁徙。在空中翱翔，在地面上奔袭。这是生物们的故事，地球上诞生的最动人的故事，这是大迁移的故事。

Life on earth is hard, perhaps nowhere harder than here and now. Every year, a timeless drama plays out on the Mara River. The elders have been through this many times. They must remember what awaits them. Their young know only the pervasive smell of fear, the instinct to stay close.

地球上的生命大多是艰难的，也许没有比现在更艰难的。每一年，在Mara河都要上演一出永恒的戏剧。老辈们已经经历许多遍。他们必须记住在等待着他们的是什么。年轻人则嗅到了恐惧的感觉，本能地待在一起。

But they must press on.

但是他们必须坚持下去。