Well, baleen whales emit sounds around 14 hertz, the deepest among mammals.

须鲸能发出 14 赫兹左右的声音，是哺乳动物中最低沉的。

Most baleen whales do not eat year-round.

大多数须鲸不是全年都在吃东西。

But the ancestors of baleen whales had a very different diet.

但是须鲸祖先的饮食习惯与这些后代的差别非常大。

Scientists studied three species of baleen whales – blue, fin and humpback.

科学家研究了三种须鲸——蓝鲸、长须鲸和座头鲸。

Perhaps, though, baleen whales might continue to evolve and get bigger still.

不过，也许须鲸会继续进化，变得更大。

We're trying to understand the behavior of baleen whales, of minke whales and humpback whales.

我们试图了解须鲸、小须鲸和座头鲸的行为。

The biggest whales of all (blue, humpback and so on) are baleen whales.

所有鲸鱼中最大的鲸类（蓝鲸、座头鲸等）是须鲸。

Now scientists think they have an idea of how baleen whales do it.

现在，科学家们认为他们已经知道须鲸是如何做到这一点的。

They say it's the first passive feeding strategy ever seen in a baleen whale.

研究人员表示，在他们目前观察到的须鲸行为中，这是第一例被动进食策略。

Baleen whales do not have teeth or vocal cords like humans and other mammals.

须鲸不像人类和其他哺乳动物那样有牙齿或声带。