Their huge mouth are the biggest in the animal kingdom and they house massive baleen plates.
它们的巨嘴是动物王国中最大的，而这大嘴中生有巨大的鲸须板。
These are used like sieves whilst feeding.
鲸须板在进食时起到筛子般的作用。
To feed, bowheads scoop in dense shoals of crustaceans along with lots of seawater.
弓头鲸进食时会将密集的大群甲壳动物与大量海水一起吞入口中。
The whales push the water out, and the crustaceans core within the baleen, then swallowed.
然后将海水吐出而将甲壳动物挡在鲸须板内咽下。
Because of the extreme cold, bowheads have a very slow metabolism and can live for over two hundred years.
由于生存环境极度寒冷，弓头鲸的新陈代谢速度极慢，它们因此可以活到两百岁以上。
Summer is a time of plenty for most, but for polar bears, finding food is becoming difficult.
夏季对大多数(动物)来说都是个富足的季节，但是对北极熊来说，觅食正变得愈发困难。
Their hunting platform, the sea ice, is disappearing beneath their feet. Without the ice, it's almost impossible to catch seals in the open ocean.
它们的捕猎平台-海冰，正在脚下消失。没有了冰层，要在开阔水面捕捉到海豹几乎是不可能的。
For a hungry bear, an unsuspecting guillemot is not below consideration.
对于饥饿的北极熊，不期而遇的海鸠也能让它杀机顿起。
But guillemots are agile swimmers, and when they dive, the bear can not follow them.
不过海鸠是敏捷的游水好手，一旦潜入水中北极熊就无法尾随其后了。
Though wet makes hunting more difficult, polar bears can swim great distances.
尽管海水使捕食更加困难，北极熊却能游很远的距离。
They've been known to swim up to a hundred kilometers in a day.
它们可以在一天之内游到一百公里的里程。
They have huge poshly webbed feet that make effective paddles
它们有完美的蹼状脚掌，划起水来像船桨一般。
But aquatic stalking expense vital energy reserves and is rarely successful.
但在水中跟踪猎物要耗费大量体能，所以很少能成功。
As the ice floors melt, bears head for solid ground.
随着冰面融化，北极熊纷纷向陆地进发。
By June, the ice is virtually disappeared from the southern stretches of the Arctic Ocean.
到了六月，北冰洋南部的冰层实际上已完全消失了。
With no ice floors to hold out on, a colony of pacific walrus has taken up residence on the beach.
没有了冰面可栖息，一群太平洋海象来到海滩上休息。