A Fish That 'Sings' Love Songs?

A Fish That 'Sings' Love Songs?

This is the sound of a fish "singing:"

Hmmmmmmmm.

It is a male fish — a plainfin midshipman, to be exact — from the Pacific Ocean. He is singing, or humming, a love song to get female fish to come and visit the nest he built for their eggs.

Scientists have wanted to know why the male plainfin midshipman sings only at night. A study published in the journal Current Biology provides some answers.

Laboratory experiments showed that the fish’s song, that low, fog-horn-like sound, is controlled partly by a hormone¹, melatonin.

Hormones² are natural substances that influence how bodies grow or develop. In the human body, melatonin tells us when it is time to sleep.

Andrew Bass³ is a professor of neurobiology and behavior at Cornell University in New York State. For nearly 30 years, he has been studying the plainfin midshipman, and the sounds they make.

Bays 'alive' with sound

"It was always remarkable⁴ how right after nightfall, if you are recording⁵ from a bunch of nests in a bay, the bay just comes alive with this sound. It’s like it suddenly turns on at night...”

Plainfin midshipmen are olive-brown in color. They grow to be up to 38 centimeters long.

The fish gets its name from rows of organs lined up on its underside. These rows are bio-luminescent. They produce light and shine in the water.

Long ago, people thought they looked like the buttons on navy clothes.

In the late spring and summer, the males move from waters deep in the ocean to more shallow waters close to land. There they build nests for females to leave their eggs under rocky shelters.

Then, during the night, the males produce their sounds. Often a group of them gather together and start humming.

But how do they make these sounds?

Unlike people speaking, or birds singing, you cannot see the fish making the sound. It comes from organs inside. Their gas-filled swim bladder and their vocal⁶ muscles help them sing.

Bass says the vocal muscles are hidden deep inside the fishes’ bodies.

Good vibrations⁸?

“And they contract those muscles at very high rates, and that vibrates the swim bladder, and that in turn generates a vibration⁷ in the surrounding water that makes the sound.”

They can make that sound, non-stop, for hours at a time. But once a female arrives, mating begins, and she leaves her eggs, the male stops singing for the night. It is the male that then watches over the eggs until they hatch — and the young fish can swim on their own.

The fish experiments were done in a Cornell laboratory by then-student Ni Feng, who is now at Yale University. It was her idea to study how melatonin affects the fish. The researchers had no idea how the hormone might affect the fishes’ ability to sing and hum.

All about the rhythm

The fish were kept in rooms where lighting⁹ could be controlled. When it was always dark, the fish hummed as they would at night. They followed their internal timing¹⁰ or circadian rhythm.

But in bright lighting, a condition that lowers melatonin production, humming was suppressed. When kept in normal light, but given a melatonin replacement¹¹, they continued to hum but at unpredictable times.

So unlike humans, and even birds, the melatonin did not put the fish to sleep. It had just the opposite effect.

Andrew Bass says the study shows how “incredibly versatile” hormones are.

“So here we study melatonin in our animal, right? And instead of suppressing calling, or putting them to sleep, essentially¹², it somewhat acts as a stimulant¹³. Again, it’s the “go” signal that says ok, make more hums...”

He says that by studying how different animals react to melatonin, researchers will get a better understanding of how it works.

“We will reveal very fundamental mechanisms¹⁴ of just how this hormone in fact controls daily sleep/wake cycles in all animals.”

The hum of space aliens?

The midshipman fish are not the only ones making sounds. In fact, long ago, fishermen would listen carefully to hear where the fish were. Bass says he even found a report written in 1924 about the plainfin midshipman and how they hum at night.

In the 1980s, people living on houseboats along the California coast did not know what to make of those sounds. Bass said they thought the sound came from either an underwater power line, a nearby water treatment center, a U.S. Navy experiment, or maybe even beings from other planets.

The boat owners found out the sound was coming from the male midshipman, looking for love in the night.

Like whales and dolphins, other sea creatures, the midshipman fish make different kinds of sounds for social communication. For example, the sound they make when protecting their nests from possible invaders¹⁵ is different than the one they make when calling a mate.

Bass says that in the end, humans and other animals are similar in certain behaviors -- in this case, the ability to produce sounds. He says these fish, and the things he learns about them, never cease to amaze him.

Words in This Story

nest – n. a place where an animal or insect lives and usually lays eggs or takes care of its young

hormone – n. natural substances that influence how bodies grow or develop

bio-luminescent – adj. something that glows and produce light in the water

swim bladder – n. a gas-filled organ in fish that help them move up or down in the water

larynx – n. muscles in a human’s throat that produce sound, also called a “voice box”

vibrate – v. to move back and forth¹⁶ or from side to side with very short, quick movements

hatch – v. to come out of an egg

circadian rhythm – n. physical, mental and behavioral changes that follow a 24-hour cycle, mostly connected to light and darkness in an organism’s environment

amaze – v. to surprise and sometimes confuse someone very much

1 hormone   

n.荷尔蒙，激素，内分泌

参考例句：

• Hormone implants are used as growth boosters.激素植入物被用作生长辅助剂。
• This hormone interacts closely with other hormones in the body.这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。

2 hormones   

n. 荷尔蒙，激素 名词hormone的复数形式

参考例句：

• This hormone interacts closely with other hormones in the body. 这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。
• The adrenals produce a large per cent of a man's sex hormones. 肾上腺分泌人体的大部分性激素。

3 bass   

n.男低音(歌手)；低音乐器；低音大提琴

参考例句：

• He answered my question in a surprisingly deep bass.他用一种低得出奇的声音回答我的问题。
• The bass was to give a concert in the park.那位男低音歌唱家将在公园中举行音乐会。

4 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。

5 recording   

n.录音，记录

参考例句：

• How long will the recording of the song take?录下这首歌得花多少时间？
• I want to play you a recording of the rehearsal.我想给你放一下彩排的录像。

6 vocal   

adj.直言不讳的；嗓音的；n.[pl.]声乐节目

参考例句：

• The tongue is a vocal organ.舌头是一个发音器官。
• Public opinion at last became vocal.终于舆论哗然。

7 vibration   

n.颤动，振动；摆动

参考例句：

• There is so much vibration on a ship that one cannot write.船上的震动大得使人无法书写。
• The vibration of the window woke me up.窗子的震动把我惊醒了。

8 vibrations   

n.摆动( vibration的名词复数 )；震动；感受；（偏离平衡位置的）一次性往复振动

参考例句：

• We could feel the vibrations from the trucks passing outside. 我们可以感到外面卡车经过时的颤动。
• I am drawn to that girl; I get good vibrations from her. 我被那女孩吸引住了，她使我产生良好的感觉。 来自《简明英汉词典》

9 lighting   

n.照明，光线的明暗，舞台灯光

参考例句：

• The gas lamp gradually lost ground to electric lighting.煤气灯逐渐为电灯所代替。
• The lighting in that restaurant is soft and romantic.那个餐馆照明柔和而且浪漫。

10 timing   

n.时间安排，时间选择

参考例句：

• The timing of the meeting is not convenient.会议的时间安排不合适。
• The timing of our statement is very opportune.我们发表声明选择的时机很恰当。

11 replacement   

n.取代，替换，交换；替代品，代用品

参考例句：

• We are hard put to find a replacement for our assistant.我们很难找到一个人来代替我们的助手。
• They put all the students through the replacement examination.他们让所有的学生参加分班考试。

12 essentially   

adv.本质上，实质上，基本上

参考例句：

• Really great men are essentially modest.真正的伟人大都很谦虚。
• She is an essentially selfish person.她本质上是个自私自利的人。

13 stimulant   

n.刺激物，兴奋剂

参考例句：

• It is used in medicine for its stimulant quality.由于它有兴奋剂的特性而被应用于医学。
• Musk is used for perfume and stimulant.麝香可以用作香料和兴奋剂。

14 mechanisms   

n.机械( mechanism的名词复数 )；机械装置；[生物学] 机制；机械作用

参考例句：

• The research will provide direct insight into molecular mechanisms. 这项研究将使人能够直接地了解分子的机理。 来自《简明英汉词典》
• He explained how the two mechanisms worked. 他解释这两台机械装置是如何工作的。 来自《简明英汉词典》

15 invaders   

入侵者，侵略者，侵入物( invader的名词复数 )

参考例句：

• They prepared to repel the invaders. 他们准备赶走侵略军。
• The family has traced its ancestry to the Norman invaders. 这个家族将自己的世系追溯到诺曼征服者。

16 forth   

adv.向前；向外，往外

参考例句：

• The wind moved the trees gently back and forth.风吹得树轻轻地来回摇晃。
• He gave forth a series of works in rapid succession.他很快连续发表了一系列的作品。