时差N小时 海洋生物有趣的睡觉习惯

Many people know that marine¹ mammals, like whales, porpoises² and dolphins, breathe air, like wedo.

大多数人都知道些海洋哺乳动物，比如鲸鱼，鼠海豚和海豚。它们和我们一样都要呼吸空气。

But, many people don't know that marine mammals have developed some interesting sleepinghabits in order to accommodate their regular trips up to the surface for air.

但是大多数人都不知道这些哺乳动物已经养成了一些有趣的睡眠习惯，以配合来回水面呼吸空气。

Today, A Moment ofScience looks at what its like to sleep with the fishes.

今天，科学一刻将探究一下，这些哺乳动物是如何像鱼类一样睡觉的。

Unlike our own breathing, which does not require conscious effort, marine mammals mustconsciously go to the surface of the water to breathe through a blowhole on top of their heads.

与人类“无意识”呼吸不同，这些动物必须到水面，通过头顶的气孔，进行“有意识”的呼吸。

Because of this, marine mammals don't sleep for a solid 8 hours a night, the way we do.

因此，它们不像我们，每晚能够稳定的睡上八小时。

Some marine mammals sleep while swimming.

有些海洋哺乳动物边睡觉边游动。

Whales nap for brief periods while swimmingalongside an alert friend who guides them.

对于鲸鱼，只要有同伴放风，并引导着，他们就会边游边打会个盹。

In fact, young whales must sleep alongside their motherbecause the mother's slipstream actually pulls the calf³ along: it will sink if the mother stops.

实际上，幼鲸必须在母鲸身边睡觉，因为母鲸游动时产生的水流可以推动幼崽向前：如果母鲸停止游动，幼崽就会沉下去。

Other marine mammals, like dolphins, sleep while floating on the surface of the water or take shortcatnaps while floating below the surface.

而其它海洋哺乳动物，像海豚，睡觉的时候是浮在水面上，打盹的时候就浮在水面下。

Researchers claim that while marine mammals sleep theirbrain is always partially⁴ alert.

研究表明，海洋哺乳动物睡觉时，他们部分大脑依然保持警觉。

Aside from these brief naps, dolphins are active most of the night.

海豚在晚上，除了打盹，其余时间都处于活跃状态。

Of course, marine mammals are equipped to handle underwater sleeping.

当然，也有些海洋哺乳动物具备水下睡觉的能力。

They haveproportionately larger lungs, exchange air more fully⁵ at each breath, and carry more oxygen intheir blood than we do, so they can hold their breath long enough to sleep with the fishes.

相应地，他们的肺都很大，每次呼吸都能换进更多的空气。他们的血液中的含氧量就比我们的高，这样他们就能长时间屏息，像鱼类一样睡觉。

1 marine   

adj.海的；海生的；航海的；海事的；n.水兵

参考例句：

• Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
• When the war broke out,he volunteered for the Marine Corps.战争爆发时，他自愿参加了海军陆战队。

2 porpoises   

n.鼠海豚( porpoise的名词复数 )

参考例句：

• A shoal of porpoises are well on the feed. 一群海豚正在吞食。 来自辞典例句
• In 1928 some porpoises were photographed working like beavers to push ashore a waterlogged mattress. 1928年有人把这些海豚象海狸那样把一床浸泡了水的褥垫推上岸时的情景拍摄了下来。 来自辞典例句

3 calf   

n.小牛，犊，幼仔，小牛皮

参考例句：

• The cow slinked its calf.那头母牛早产了一头小牛犊。
• The calf blared for its mother.牛犊哞哞地高声叫喊找妈妈。

4 partially   

adv.部分地，从某些方面讲

参考例句：

• The door was partially concealed by the drapes.门有一部分被门帘遮住了。
• The police managed to restore calm and the curfew was partially lifted.警方设法恢复了平静，宵禁部分解除。

5 fully   

adv.完全地，全部地，彻底地；充分地

参考例句：

• The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气，然后全部呼出。
• They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。