纪录片《我们的地球》 第51期 淡水资源(08)（在线收听）

Lines of wildebeest are on the march.

一队队的角马正在迁徙途中

Each year, nearly two million animals migrate across the Serengeti Plains in search of fresh, green pastures.

每年都会有将近200万只角马横越塞伦盖蒂平原，去寻找新鲜草场

For these thirsty herds,

对于这群饥渴难耐的角马来说

the rivers are not only a vital source of drinking water but also dangerous obstacles.

河流不仅是唯一能解渴的重要水源，也是充满危险的关隘

This is one of the largest concentrations of Nile crocodiles in Africa, giants that grow over five metres long.

这里是非洲一处最大的尼罗鳄聚集地，这些大怪物能长到5米多长

From memory, the crocodiles know the wildebeest are coming and gather in anticipation.

鳄鱼凭着记忆得知，角马已经来了，不出所料，它们纷纷下水

The crocodile's jaws snap tight like a steel trap.

鳄鱼的巨口像捕兽铗一般紧咬住猎物

Once they have a hold, they never let go.

一旦被它逮住，猎物再无逃脱的机会

It took over an hour to drown this full-grown bull.

它得花上一个多小时才能淹死这只成年公角马

To surprise their prey, crocodiles must strike with lightning speed.

为了突袭猎物，鳄鱼必须以闪电般的速度出击

Here, only the narrowest line separates life from death.

在这里，生与死只有一线之隔。