VOA科学技术2023 研究发现北象海豹每天只睡两小时

Sleep is an important biological process for people and animals.

睡眠对人和动物来说都是一个重要的生物过程。

However, much remains¹ unknown about the process.

然而，这一过程仍有许多未解之谜。

Humans spend about one third of their lives sleeping. But some mammals, like the northern elephant seal, survive with much less sleep.

人类一生中大约有1/3的时间都在睡觉。但一些哺乳动物，如北象海豹，睡眠很少也能生存。

Researchers in a new study described the unusual sleep pattern of these ocean animals. They found that when these mammals go to feed on trips that can last seven months, they sleep just two hours. Those two hours of sleep are made up of short moments of rest lasting² only 10 minutes each as they dive deep to avoid predators³. The only other mammals known to get so little sleep are African elephants.

研究人员在一项新的研究中描述了这些海洋动物不同寻常的睡眠模式。他们发现，当这些哺乳动物在长达7个月的觅食之旅时，它们只睡两个小时。这两个小时的睡眠是由每次只持续10分钟的短暂睡眠组成的，它们会深潜以躲避捕食者。其他已知睡眠如此之少的哺乳动物只有非洲象。

The seals' sleep time during ocean trips is different from the 10 hours a day they spend sleeping on the coast during mating season at places like California's Ano Nuevo beach.

海豹在海洋之旅中的睡眠时间跟交配季节它们在加州安诺纽沃海滩等地每天10小时的睡眠完全不同。

The researchers placed a head covering with sensors⁴ on the heads of the seals that they studied. The sensors recorded sleep signals created by the seals' brains and heart rate. The sensors also recorded the animals' location and depth beneath the sea.

研究人员在他们研究的海豹头上戴上了一个附传感器的头罩。传感器记录了由海豹大脑和心率产生的睡眠信号。传感器还记录了这些动物在海底的位置和深度。

The researchers studied female seals because they go out on long open-ocean trips while males feed in coastal⁵ waters.

研究人员对雌性海豹进行了研究，因为它们会进行长时间的公海旅行，而雄性海豹则在沿海水域觅食。

During dives lasting about 30 minutes, the seals went into a deep sleep called slow-wave sleep while keeping a controlled downward movement. When they then experienced rapid-eye-movement (REM) sleep, a condition where voluntary movement while sleeping stops, the seals fell into a turning pattern. They sometimes ended up without movement on the seafloor.

在持续30分钟的潜水过程中，海豹会进入一种被称为慢波睡眠的深度睡眠，同时保持可控的下潜运动。然后，当它们经历快速眼动睡眠时，这时睡眠中的自主运动会停止，它们进入螺旋下沉模式。它们有时候最终会落到海底不再移动。

Jessie Kendall-Nar of the University of California San Diego's Scripps Institution of Oceanography is the lead writer of the study published this week in Science. She said, "Then, at the deepest point of their sleeping dive - up to 377 meters deep - they wake up and swim back to the surface."

加州大学圣地亚哥分校斯克里普斯海洋研究所的杰西·肯德尔·纳尔是这项本周发表在《科学》杂志上的研究的主要作者。她说：“然后，在他们睡眠下潜的最深处——高达377米——它们醒过来，再游回海面。”

The northern elephant seal is the world's second-largest seal. Only the southern elephant seal is bigger. Male northern elephant seals may reach four meters long and weigh up to 2,000 kilograms. Females reach about three meters in length and 590 kilograms.

北象海豹是世界第二大海豹。只有南象海豹体型更大。雄性北象海豹身长可达4米，体重可达两吨。雌性身长约3米，体重590公斤。

The seals eat sea animals like fish and squid. Even with their large size, predators like sharks and killer⁶ whales are still a threat.

海豹以鱼类和鱿鱼等海洋动物为食。即使体型巨大，鲨鱼和虎鲸等食肉动物对它们来说仍然是一种威胁。

Terrie Williams is a scientist at the University of California at Santa Cruz who helped write the study. She said, "It is remarkable⁷ that a wild animal will fall into deep, paralytic⁸ REM sleep when there are predators on the hunt." She added that the seals solve this problem by going into deep sleep in the deep parts of the oceans where predators usually do not hunt them.

特里·威廉姆斯是加州大学圣克鲁斯分校的一名科学家，她帮助撰写了这项研究。她说：“当有捕食者在狩猎时，野生动物进入深度、麻痹性的快速眼动睡眠是很异常的。”她还表示，海豹通过在通常不会有捕食者的深海进入深度睡眠来解决这个问题。

Williams said the brain's ability to control awakening⁹ the sleeping seals at a depth before they drown is also a discovery about how mammalian brains work. She commented on this saying that it shows the survival¹⁰ control of the seals' brains.

威廉姆斯说，大脑能够在熟睡的海豹溺水前将其唤醒，这也是对哺乳动物的大脑如何工作的一个发现。她就此发表评论说，这表明了海豹大脑的生存控制。

1 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

2 lasting   

adj.永久的，永恒的；vbl.持续，维持

参考例句：

• The lasting war debased the value of the dollar.持久的战争使美元贬值。
• We hope for a lasting settlement of all these troubles.我们希望这些纠纷能获得永久的解决。

3 predators   

n.食肉动物( predator的名词复数 )；奴役他人者（尤指在财务或性关系方面）

参考例句：

• birds and their earthbound predators 鸟和地面上捕食它们的动物
• The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》

4 sensors   

n.传感器，灵敏元件( sensor的名词复数 )

参考例句：

• There were more than 2000 sensors here. 这里装有两千多个灵敏元件。 来自《简明英汉词典》
• Significant changes have been noted where sensors were exposed to trichloride. 当传感器暴露在三氯化物中时，有很大变化。 来自辞典例句

5 coastal   

adj.海岸的，沿海的，沿岸的

参考例句：

• The ocean waves are slowly eating away the coastal rocks.大海的波浪慢慢地侵蚀着岸边的岩石。
• This country will fortify the coastal areas.该国将加强沿海地区的防御。

6 killer   

n.杀人者，杀人犯，杀手，屠杀者

参考例句：

• Heart attacks have become Britain's No.1 killer disease.心脏病已成为英国的头号致命疾病。
• The bulk of the evidence points to him as her killer.大量证据证明是他杀死她的。

7 remarkable   

adj.显著的，异常的，非凡的，值得注意的

参考例句：

• She has made remarkable headway in her writing skills.她在写作技巧方面有了长足进步。
• These cars are remarkable for the quietness of their engines.这些汽车因发动机没有噪音而不同凡响。

8 paralytic   

adj. 瘫痪的 n. 瘫痪病人

参考例句：

• She was completely paralytic last night.她昨天晚上喝得酩酊大醉。
• She rose and hobbled to me on her paralytic legs and kissed me.她站起来，拖着她那麻痹的双腿一瘸一拐地走到我身边，吻了吻我。

9 awakening   

n.觉醒，醒悟 adj.觉醒中的；唤醒的

参考例句：

• the awakening of interest in the environment 对环境产生的兴趣
• People are gradually awakening to their rights. 人们正逐渐意识到自己的权利。

10 survival   

n.留住生命，生存，残存，幸存者

参考例句：

• The doctor told my wife I had a fifty-fifty chance of survival.医生告诉我的妻子，说我活下去的可能性只有50%。
• The old man was a survival of a past age.这位老人是上一代的遗老。