Name: 【TED-Ed】鯨魚為什麼會唱歌？- Stephanie Sardelis (【TED-Ed】Why do whales sing? - Stephanie Sardelis)
Uploaded: 2021-01-14T06:41:38.000Z
Duration: 5 min 13 s

Light and odors don't travel well, so it's hard for animals to see or smell.

光和氣味不易被傳遞，所以動物很難目視或嗅聞

But sound moves about four times faster in water than in air,

但是在水中，聲音的傳播速度大約比在空氣中快四倍

marine mammals often rely on vocalization to communicate.

哺乳類動物經常只靠聲音來溝通，

That's why a chorus of sounds fills the ocean.

But the most famous parts of this underwater symphony

are the evocative melodies, or songs, composed by the world's largest mammals,

就是令人激發聯想的旋律、或是歌聲，出自於世界上最大的哺乳類動物

Whale songs are one of the most sophisticated communication systems

鯨魚的歌曲是動物王國中最精密的

which use hairy baleen plates instead of teeth to trap their prey.

Meanwhile, toothed whales do use echolocation,

and they and other species of baleen whales

make social sounds, such as  cries and whistles, to communicate.

發出社交聲音來社交，像是哭聲和哨聲來溝通

But those vocalizations lack the complexity of songs.

Land mammals like us generate sound by moving air over our vocal cords

人類等陸地哺乳類動物，藉由空氣通過聲帶來發聲

當我們吐氣時，使聲帶振動發聲

Baleen whales have a U-shaped fold of tissue between their lungs

鬚鯨的肺部之間有Ｕ型摺疊組織，介於肺

and their large inflatable organs called laryngeal sacs.

和大型、可充氣的器官喉囊之間

because it's essentially impossible to observe the internal organs

因為基本上我們不可能觀察正在唱歌的鯨魚

muscular contractions in the throat and chest

move air from the lungs across the U-fold and into the laryngeal sacs,

讓肺部的空氣通過Ｕ型摺疊組織來到喉囊，

The resulting sound resonates in the sacs like a choir singing in a cathedral

最後，聲音在喉囊中共鳴，如同唱詩班在教堂中歌唱，

making songs loud enough to propagate up to thousands of kilometers away.

使聲音大到足以傳播到上千公里外的距離

Instead, the air is recycled back into the lungs,

One reason whale songs are so fascinating is their pattern.

鯨歌迷人之處之一在於其樣式，

Units, like moans, cries, and chirps are arranged in phrases.

如沉吟，尖叫、呼喊等單元構成了樂句

Repeated phrases are assembled into themes.

Multiple themes repeated in a predictable pattern create a song.

多個重複的主旋律，依可預測的樣式組成一曲鯨歌

This hierarchical structure is a kind of grammar.

這種階級式的歌曲架構是一種語法

Whale songs are extremely variable in duration,

鯨歌演唱的時間有長有短，差距甚大

and whales can repeat them over and over.

In one recorded session, a humpback whale sang for 22 hours.

在一個錄音中，一頭座頭鯨連唱了 22 小時

We don't yet know the exact purpose, but we can speculate.

我們不能確定確切的目的，但我們能猜測

Given that the singers are males and they mostly sing during the mating season,

由於唱歌的通常是雄性，而唱歌的時間多半在交配季，

Or perhaps they're territorial, used to deter other males.

或是牠們保衛領地，驅趕其他雄性

Whales return to the same feeding and breeding grounds annually,

鯨魚每年都會回到同個地點繁殖、哺育後代，

and each discrete population has a different song.

Songs evolve over time as units or phrases are added, changed, or dropped.

這些歌曲隨時間演化，新增、改變或刪減單元與樂句，

And when males from different populations are feeding within earshot,

當聽力範圍內，不同聚落的雄鯨覓食時，

maybe because new songs make them more attractive to breeding females.

也許是新歌對育齡的雌鯨更具吸引力

This is one of the fastest examples of cultural transmission,

這是文化傳播最快速的例子之一，

where learned behaviors are passed between unrelated individuals

習得的行為在同一物種，但無親屬關係的

We can eavesdrop on these songs using underwater microphones

我們可以用一種叫做水聽器的水下麥克風

These help us track species when sightings or genetic samples are rare.

這可以幫助我們追蹤罕見或稀有基因樣本的物種

For example, scientists have been able to differentiate

the elusive blue whale's populations worldwide based on their songs.

分布於是世界各地的隱匿藍鯨鯨群

But the oceans are getting noisier as a result of human activity.

and seismic surveys for oil are occurring more often

which may interfere with whale's communication.

Some whales will avoid key feeding or breeding grounds

有些鯨魚甚至會因為人為噪音太大，

And humpback whales have been observed to reduce their singing

我們觀察到，座頭鯨會因為 200 公里外的噪音，

in response to noise 200 kilometers away.

Limiting human activity along migratory routes

和其他重要棲息地限制人為活動，

and reducing noise pollution throughout the ocean

would help ensure whales continued survival.

If the whales can keep singing and we can keep listening,

如果鯨魚能一直唱歌，我們能一直聆聽，

maybe one day we'll truly understand what they're saying.

或許有一天我們能真正聽懂牠們在說甚麼

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【TED-Ed】鯨魚為什麼會唱歌？- Stephanie Sardelis (【TED-Ed】Why do whales sing? - Stephanie Sardelis)

sophisticated

essentially

pattern

critical