witnessed a swarm of electric eels leap out of the water

看到一群電鰻躍出水面

to defend themselves against oncoming horses.

以防備迎面而來的馬匹。

Most people thought the story so unusual that Humboldt made it up.

大多數人都認為這個故事很不尋常，所以洪堡編造了這個故事。

But fish using electricity is more common than you might think;

但魚用電比你想象的要普遍。

and yes, electric eels are a type of fish.

是的，電鰻是魚的一種。

Underwater, where light is scarce,

在水下，光線稀少的地方。

electrical signals offer ways to communicate,

電信號提供了溝通的方式。

navigate,

導航。

and find—plus, in rare cases, stun—prey.

和發現加，在極少數情況下，眩暈捕獵。

Nearly 350 species of fish have specialized anatomical structures

近350種魚類有專門的解剖結構

that generate and detect electrical signals.

產生和檢測電信號的。

These fish are divided into two groups,

這些魚分為兩類。

depending on how much electricity they produce.

根據其發電量的多少。

Scientists call the first group the weakly electric fish.

科學家稱第一類為弱電魚。

Structures near their tails called electric organs

靠近尾巴的結構被稱為電器官

produce up to a volt of electricity, about two-thirds as much as a AA battery.

產生的電量可達1伏，約為AA電池的三分之二。

How does this work?

這怎麼操作呢？

The fish's brain sends a signal through its nervous system to the electric organ,

魚'的大腦通過神經系統向電器官發出信號。

which is filled with stacks of hundreds

充滿了成堆的

or thousands of disc-shaped cells called electrocytes.

或數以千計的盤狀細胞，稱為電細胞。

Normally, electrocytes pump out sodium and potassium ions

正常情況下，電細胞會泵出鈉離子和鉀離子。

to maintain a positive charge outside and negative charge inside.

以保持外面帶正電，裡面帶負電。

But when the nerve signal arrives at the electrocyte,

但當神經信號到達電細胞時。

it prompts the ion gates to open.

它提示離子門打開。

Positively charged ions flow back in.

帶正電的離子迴流。

Now, one face of the electrocyte is negatively charged outside

現在，電細胞的一個面在外面帶負電。

and positively charged inside.

且內部帶正電。

But the far side has the opposite charge pattern.

但遠方的電荷模式卻與之相反。

These alternating charges can drive a current,

這些交變電荷可以驅動電流。

turning the electrocyte into a biological battery.

將電細胞變成生物電池。

The key to these fish's powers is that nerve signals are coordinated

這些魚的能力的關鍵是神經信號的協調性

to arrive at each cell at exactly the same time.

在同一時間到達每個單元。

That makes the stacks of electrocytes act like thousands of batteries in series.

這使得堆積的電細胞就像成千上萬的電池串聯起來一樣。

The tiny charges from each one add up to an electrical field

每個人身上的微小電荷加起來就是一個電場。

that can travel several meters.

可以傳播數米的。

Cells called electroreceptors buried in the skin

埋在皮膚裡的細胞叫電感受器。

allow the fish to constantly sense this field

讓魚兒不斷地感知這個領域

and the changes to it caused by the surroundings or other fish.

以及周圍環境或其他魚類對其造成的變化。

The Peter’s elephantnose fish, for example,

比如彼得的象鼻魚。

has an elongated chin called a schnauzenorgan

長下巴

that's riddled in electroreceptors.

那'充滿了電感受器。

That allows it to intercept signals from other fish,

這使得它可以攔截其他魚類的信號。

judge distances,

判斷距離。

detect the shape and size of nearby objects,

檢測附近物體的形狀和大小。

and even determine whether a buried insect is dead or alive.

甚至可以確定被埋的昆蟲是死是活。

But the elephantnose and other weakly electric fish

但象鼻魚等弱電魚。

don't produce enough electricity to attack their prey.

不要'產生足夠的電力來攻擊它們的獵物。

That ability belongs to the strongly electric fish,

這種能力是屬於強電魚的。

of which there are only a handful of species.

其中只有少數幾個品種。

The most powerful strongly electric fish is the electric knife fish,

最強大的強電魚是電刀魚。

more commonly known as the electric eel.

更俗稱電鰻。

Three electric organs span almost its entire two-meter body.

三個電機關幾乎橫跨了它整個兩米的身體。

Like the weakly electric fish,

比如弱電魚。

the electric eel uses its signals to navigate and communicate,

電鰻用它的信號來導航和交流。

but it reserves its strongest electric discharges for hunting

但它為狩獵保留了最強的電擊能力

using a two-phased attack that susses out and then incapacitates its prey.

使用一個兩階段的攻擊，發現，然後使其獵物喪失能力。

First, it emits two or three strong pulses,

首先，它發出兩三個強脈衝。

as much as 600 volts.

高達600伏。

These stimulate the prey's muscles, sending it into spasms

這些刺激獵物的肌肉，讓它進入痙攣狀態'。

and generating waves that reveal its hiding place.

併產生波瀾，暴露其藏身之處。

Then, a volley of fast, high-voltage discharges

然後，一連串的快速高壓放電。

causes even more intense muscle contractions.

引起更強烈的肌肉收縮。

The electric eel can also curl up so that the electric fields

電鰻也能蜷縮起來，使電場

generated at each end of the electric organ overlap.

在電器官兩端產生的重疊。

The electrical storm eventually exhausts and immobilizes the prey,

電風暴最終將獵物耗盡並固定下來。

and the electric eel can swallow its meal alive.

而電鰻能將飯菜生生吞下。

The other two strongly electric fish are the electric catfish,

另外兩種強電魚是電鯰魚。

which can unleash 350 volts

它可以釋放350伏的電壓

with an electric organ that occupies most of its torso,

有一個佔據其大部分軀幹的電動器官。

and the electric ray, with kidney-shaped electric organs on either side of its head

電鰩魚

that produce as much as 220 volts.

產生高達220伏的電壓。

There is one mystery in the world of electric fish:

在電魚的世界裡，有一個謎團。

why don't they electrocute themselves?

他們為什麼不把自己電死？

It may be that the size of strongly electric fish

可能是強電魚的大小。

allows them to withstand their own shocks,

讓他們能夠承受自身的衝擊。

or that the current passes out of their bodies too quickly.

或者說電流過快地從他們的身體裡流走。

Some scientists think that special proteins may shield the electric organs,

一些科學家認為，特殊的蛋白質可能屏蔽了電器官。

but the truth is, this is one mystery science still hasn't illuminated.

但事實是，這是一個神祕的科學仍然沒有'照明。