With fewer of their favourite prey of weddell seals resting on ice floes,
由于在浮冰上休息的偏爱猎物威德尔海豹变少，
killer whales now have no choice but to target new prey. Crabeater seals.
虎鲸现在别无选择，只能锁定新猎物。食蟹海豹。
Numbering 15 million, they're the most abundant marine mammal on earth.
数量高达五千万头，它们是地球上最多的海洋哺乳动物。
But they are a far more dangerous target than a weddell seal.
但它们这个目标却比威德尔海豹更加危险。
Stronger... and more inclined to fight back.
更强壮，也更勇于反击。
But each member of this pod needs to eat a seal a day.
可是这个鲸群的每个成员每日需要吃一头海豹。
So the pressure is on to feed.
因此觅食的压力不小。
They're led by a matriarch who knows exactly what to do.
领导它们的雌性族长，深知该如何去做。

Living 100 years or more, she has plenty of hunting experience to draw upon.
活了至少一百岁的它，有丰富的狩猎经验可供汲取。
With the ice floe having broken in two, the seals have become more vulnerable.
由于浮冰裂成两半，海豹变得岌岌可危。
The matriarch now pushes the ice floe into open water to give their next wave maximum impact.
雌性族长现在将浮冰推向无冰水域，让下一波造成最大冲击。
This requires teamwork and precision.
这需要团队合作与精准度。
She makes her final calculations.
它做出了最后计算。
This seal has only one way of escaping death.
这头海豹只有一条路能逃出生天。
Unlike the less muscular weddell seal, the crabeater has the strength to hurl itself out of the water... just in time.
不同于肌肉较少的威德尔海豹，食蟹海豹有力量能够及时一跃出水。
For the killer whales, it has been a significant waste of energy.
对虎鲸来说是白白浪费了力气。
Their need to eat is now greater than ever.
进食的急迫性现在更胜以往。