VOA慢速英语2021--Scientists Find Whales Eat … A Lot!

 

The blue whale is the largest animal to ever live on our planet. You might wonder how much such a large creature eats. Well, you are not alone.

Scientists recently carried out a study to find out how much blue whales - and some of their closest relatives - eat in a day.

Their findings were not surprising. They found the whales eat a lot.

In just one day, blue whales living in the North Pacific Ocean can eat about 14.5 metric tons of krill. Krill are crustaceans³ and look like very small shrimp⁴. That means blue whales eat around 1450 metric tons of food every year.

Matthew Savoca of Stanford University was the lead writer of the study, which appeared recently in the publication Nature. When speaking of the findings, Savoca said, "It's an unimaginable amount of food."

Nick Pyenson was the co-writer of the study. He said the amount of food blue whales eat in a day is about the weight of "one fully-loaded school bus."

Pyenson works at the Smithsonian Institution's National Museum of Natural History in Washington, D.C. He is an expert in the study of extinct marine⁵ mammals.

Savoca also described the blue whale's size as "unimaginable." Blue whales are larger than even the biggest dinosaurs⁶. They can grow to 33 meters long and weigh about 181 metric tons. The animal can grow to about the size of a Boeing 737 airplane.

For the study, the researchers followed 321 whales living in the Atlantic, Pacific and Southern oceans. Some were blue whales. The rest were six other baleen⁷ whale species: humpback, fin¹, bowhead, right, Antarctic minke and Bryde's whales. These huge ocean mammals were found to eat up to three times more food than scientists had thought.

To measure the amount of food the whales ate and to study eating behaviors, the researchers used many devices. Electronic tag devices were attached to the animal's back. They also used cameras, microphones, a GPS locator device and an instrument that follows movement. They used drones to estimate the size of a whale's mouth area and how much food it could eat at one time. And they used instruments that recorded sound waves to estimate the amount of food in the waters near the whales.

Baleen whales eat small creatures that include krill, fish or crustaceans called copepods. The largest whale species prefer krill. Smaller species such as humpback, Bryde's or minke whales can eat fish or krill.

Most baleen whales do not eat year-round. They eat about 100 days out of the year, mostly during the summer mating season. They eat very little the rest of the year.

There was another important part of the study: Knowing how much waste the whales excrete.

Because they eat so much, they also produce much more excrement⁸, or waste material, than scientists had thought.

This waste material provides important nutrients⁹ for ocean ecosystems¹¹.

By eating so much and then producing waste material, baleen whales help nutrients stay on the sea surface. These nutrients help to form phytoplankton -- extremely small organisms that take in carbon. Phytoplankton serve as the base of ocean food webs.

Whale hunting during the 20th century caused sharp drops in whale populations. Pyenson said that before whale numbers dropped from hunting, the animals were able to support "far more productive ocean ecosystems."

He added that supporting whale recovery may help repair "ecosystem¹⁰ functions lost in the past hundred years."

Words in This Story

crustacean² – n. a type of animal (such as a crab¹² or lobster) that has several pairs of legs and a body made up of sections that are covered in a hard outer shell

marine – adj. of or relating to the sea

mammal – n. a type of animal that feeds milk to its young and that usually has hair or fur covering most of its skin

baleen – n. a tough material that hangs down from the upper jaw¹³ of whales without teeth and is used by the whale to filter small ocean animals out of seawater

species – n. a group of similar living things that ranks below the genus in scientific classification and is made up of individuals able to produce offspring with one another

locator – n. one that finds something (such as a mining claim or the course of a road)

prefer – v. to like (someone or something) better than someone or something else

excrete – v. to pass (waste matter) from the body or from an organ in the body

ecosystem – n. the whole group of living and nonliving things that make up an environment and affect each other

function – n. the action for which a person or thing is designed or used

1 fin   

n.鳍；(飞机的)安定翼

参考例句：

• They swim using a small fin on their back.它们用背上的小鳍游动。
• The aircraft has a long tail fin.那架飞机有一个长长的尾翼。

2 crustacean   

n.甲壳动物；adj.甲壳纲的

参考例句：

• Seafood is a valuable lobster crustacean section.名贵海珍品龙虾属甲壳科。
• The illustrious Cuvier did not perceive that a barnacle was a crustacean.大名鼎鼎的居维叶也未看出藤壶是一种甲壳动物。

3 crustaceans   

n.甲壳纲动物（如蟹、龙虾）( crustacean的名词复数 )

参考例句：

• These crustaceans provide a valuable food source for some fish. 这些甲壳纲动物是某些鱼类重要的食物来源。 来自《简明英汉词典》
• When the tide ebbs it's a rock pool inhabited by crustaceans. 退潮时，它便成为甲壳动物居住的岩石区潮水潭。 来自辞典例句

4 shrimp   

n.虾，小虾；矮小的人

参考例句：

• When the shrimp farm is built it will block the stream.一旦养虾场建起来，将会截断这条河流。
• When it comes to seafood,I like shrimp the best.说到海鲜，我最喜欢虾。

5 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。

6 dinosaurs   

n.恐龙( dinosaur的名词复数 )；守旧落伍的人，过时落后的东西

参考例句：

• The brontosaurus was one of the largest of all dinosaurs. 雷龙是所有恐龙中最大的一种。 来自《简明英汉词典》
• Dinosaurs have been extinct for millions of years. 恐龙绝种已有几百万年了。 来自《简明英汉词典》

7 baleen   

n.鲸须

参考例句：

• Other baleen whales have splash guards too,but not like this.一些须鲸物种头顶也有护住喷水孔的构造，但并不长成这样。
• Baleen whales often appear in this region. Be careful!这一带经常有须鲸出没，要注意安全啊。

8 excrement   

n.排泄物，粪便

参考例句：

• The cage smelled of excrement.笼子里粪臭熏人。
• Clothing can also become contaminated with dust,feathers,and excrement.衣着则会受到微尘、羽毛和粪便的污染。

9 nutrients   

n.（食品或化学品）营养物，营养品( nutrient的名词复数 )

参考例句：

• a lack of essential nutrients 基本营养的缺乏
• Nutrients are absorbed into the bloodstream. 营养素被吸收进血液。 来自《简明英汉词典》

10 ecosystem   

n.生态系统

参考例句：

• This destroyed the ecosystem of the island.这样破坏了岛上的生态系统。
• We all have an interest in maintaining the integrity of the ecosystem.维持生态系统的完整是我们共同的利益。

11 ecosystems   

n.生态系统( ecosystem的名词复数 )

参考例句：

• There are highly sensitive and delicately balanced ecosystems in the forest. 森林里有高度敏感、灵敏平衡的各种生态系统。 来自《简明英汉词典》
• Madagascar's ecosystems range from rainforest to semi-desert. 马达加斯加生态系统类型多样，从雨林到半荒漠等不一而足。 来自辞典例句

12 crab   

n.螃蟹，偏航，脾气乖戾的人，酸苹果；vi.捕蟹，偏航，发牢骚；vt.使偏航，发脾气

参考例句：

• I can't remember when I last had crab.我不记得上次吃蟹是什么时候了。
• The skin on my face felt as hard as a crab's back.我脸上的皮仿佛僵硬了，就象螃蟹的壳似的。

13 jaw   

n.颚，颌，说教，流言蜚语；v.喋喋不休，教训

参考例句：

• He delivered a right hook to his opponent's jaw.他给了对方下巴一记右钩拳。
• A strong square jaw is a sign of firm character.强健的方下巴是刚毅性格的标志。