Bowheads, belugas and narwhals head for open water on the southern edge of the Arctic Ocean.

弓头鲸、白鲸以及角鲸纷纷向北冰洋南端的开阔水面游去。

Each individual bowhead will come up with their own song and improvise new ones all the time.

每只弓头鲸都会唱自己的歌，并随时即兴创作新的歌曲。

Until now it's the bowhead whale you've hunted, and it won't risk going past the warm waters of the equator.

您以前捕捉的都是平常的白鲸，它并木敢险通过赤道的温热海水。

Bowhead whales feed on plankton, while ringed seals eat fish and other animals in which mercury has had the chance to accumulate.

因鲸以浮游生物食，而环斑海豹则吃鱼和其它可能积聚汞的动物。

Those animals are only members of the genus Balaenoptera furnished with dorsal fins, and like sperm whales, they're generally smaller than the bowhead whale.

这些东西不过是鲸科，有鳍的动物，大头鲸也一样。它们通常比普通白鲸小一些啊！

Instead of the ringed seals they ate out on the ice, the bears are foraging on bowhead whale carcasses, cast up on the beach.

它们不再在冰上捕食环纹海豹，而是开始以被冲上海滩的的鲸尸体食。

One hypothesis states that bowheads might be singing so many songs because different populations are mixing together and bringing all their different songs to the mix.

有一种假设认，弓头鲸会唱这么多歌，是因不同的鲸群在融合到一起，要把所有它们不同的歌曲融合到一起。

Mice and rats reach the end of their lives after just four years, while for the bowhead whale, Earth's longest-lived mammal, death can come after 200.

老鼠们的寿命不过4年。但是对于地球上寿命最长的哺乳动物 弓头鲸来说，死亡在200年后才会发生。