How squids outsmart their predators - Carly Anne York

翻译人员: Yuntao Li 校对人员: Lipeng Chen

In the ocean’s depths, two titans wage battle:

在海洋深处， 两位狠角色正在龙争虎斗——

the sperm whale and the colossal squid.

—只抹香鲸和大王乌贼。

Sperm whales use echolocation to hunt these squid for food,

巨头鲸会用回声定位 来捕食大王乌贼，

but even against this gigantic animal, squid can put up an impressive fight.

但就算是面对如此强劲的对手， 大王乌贼也不甘示弱。

Scientists know this because on the bodies of washed-up whales,

科学家得出此结论是因为他们 经常能从搁浅的鲸鱼身上

they frequently find huge, round suction scars,

发现由强吸力造成的 巨大的圆形伤疤，

emblazoned there by large, grasping tentacles.

那是被巨大的触角 吸附后留下的印记。

Ranging in size from this giant’s impressive 14 meters

大小可以从令人惊叹的 14 米长的大王乌贼

to the 2.5 centimeters of the southern pygmy squid,

到 2.5 厘米长的 南太平洋侏儒鱿鱼，

these creatures fall into the group of animals known as cephalopods.

这些生物在动物中属 头足类的无脊椎动物。

There are about 500 squid species worldwide,

全球大概有 500 余种 鱿鱼种类，

and they live in all the world’s oceans,

生存区域遍布全球海域，

making them a reliable food source for whales,

这让它们成为鲸鱼、

dolphins,

海豚、

sharks,

鲨鱼、

seabirds,

fish,

海鸟、

鱼，

and even other squid.

甚至是其他鱿鱼的完美食物来源。

Indeed, squid themselves are fearsome ocean predators.

虽然鱿鱼是海中的可怕的掠食者，

But their most extraordinary adaptations

但他们在进化史上最令人惊叹的，

are those that have evolved to help them thwart their predators.

还是它们已经进化得 可以对抗它们的捕食者。

Squid, which can be found mainly

鱿鱼，通常成群的出没在浅滩上， 河口、深海以及开放性水域。

in estuarine, deep-sea, and open-water habitats,

often swim together in shoals.

Being out in the open without anywhere to hide makes them vulnerable,

但没有躲避的地方， 暴露在外让它们非常脆弱。

so as a first line of defense, they rely on large, well-developed eyes.

所以它们把进化完全的大眼睛 作为它们的首要防范机制。

In the colossal squid, these are the size of dinner plates,

它们的眼睛可以达到主餐盘大小，

the largest known eyes in the animal kingdom.

大王乌贼拥有动物中最大的眼睛。

When it’s dark or the water is murky, however,

但是，当光线不足或是水域浑浊时，

squid rely on a secondary sensory system,

大王乌贼会依靠它的第二传感系统。

made from thousands of tiny hair cells that are only about twelve microns long

数以千记的微小毛细胞， 长度仅 12 微米，

and run along their heads and arms.

长在它们头和触角上。

Each of these hair cells is attached to axons in the nervous system.

每一根毛细胞都附着在 神经系统的轴突上。

Swimming animals create a wake,

有动物游过时，会造成一层层波动。

so when the hairs on the squid’s body detect this motion,

当乌贼身上的毛细胞感受到波动时， 会向大脑发送信号，

they send a signal to the brain,

信号会帮助大脑判断 水纹波动的方向。

which helps it determine the direction of the water’s flow.

这样， 即使是在光线非常微弱的环境下，

This way, a squid can sense an oncoming predator in even the dimmest waters.

鱿鱼们还是可以 预测到掠食者的方向。

Aware of the threat, a squid can then mask itself from a predator.

在预知到危险的情况下， 鱿鱼可以伪装自己不被捕食者发现。

Squid skin contains thousands of tiny organs called chromatophores,

鱿鱼的皮肤包含上千个 环绕着肌肉的色素细胞，

each made of black, brown, red or yellow pigments and ringed in muscle.

每个细胞都呈黑、棕、红或黄色。

Reflecting cells beneath the chromatophores

长在色素细胞下的反射细胞会

mirror the squid’s surroundings, enabling it to blend in.

映射鱿鱼周围的环境， 以便它们伪装自己。

So, when the muscles contract,

所以，当肌肉收缩时，

the color of the pigment is exposed,

颜色显露出来，

whereas when the muscles relax the colors are hidden.

当肌肉松弛放松时，颜色就会消失。

Each of these chromatophores

每一个色素细胞

is under the individual control of the squid’s nervous system,

都是受鱿鱼的 神经细胞单独控制的。

so while some expand, others remain contracted.

所以这些细胞可以 部分收缩，部分放松。

That enables countershading,

这让鱿鱼可以进行“反荫蔽”，

where the underside of the squid is lighter than the top,

鱿鱼的肚子颜色会比背部颜色浅。

to eliminate a silhouette that a predator might spy from below.

这样就不会造成剪影， 以防捕食者从下方偷袭。

Some predators, however, like the whales and dolphins,

但是有些捕食者，比如鲸鱼和海豚，

get around this ruse by using sound waves to detect a squid’s camouflaged form.

会利用声波来检测鱿鱼的伪装。

Not to be outfoxed, the squid still has two more tricks up its sleeve.

为了不被以智取胜， 鱿鱼还是留了两招。

The first involves ink, produced inside its mantle.

第一就是它的身体可以分泌出墨汁。

Squid ink is made mostly of mucus and melanin,

鱿鱼的墨汁大部分是由粘液

which produces its dark coloring.

和生成黑色的黑色素构成。

When squid eject the ink,

当鱿鱼喷出墨汁时，

they either use it to make a large smokescreen

亦是会喷出大片的黑色墨汁

that completely blocks the predator’s view

来完全阻挡住捕食者的视线，

or a blob that roughly mimics the size and shape of the squid.

亦或是吐出和鱿鱼体型 形状大致一样的墨团。

This creates a phantom form, called a pseudomorph,

墨团会行成一个叫做 “伪形”的假鱿鱼

that tricks the predator into thinking it’s the real squid.

来迷惑捕食者， 让他们以为“伪形”是真的鱿鱼。

As a final touch, squid rely on jet propulsion

最后，鱿鱼会依靠使劲喷射让自己

to rapidly shoot away from their hunters,

快速地逃离捕食者所在地点，

reaching speeds of up to 25 miles per hour and moving meters away in mere seconds.

它们的喷射速度可以 达到每小时 25 英里，

在短短几秒钟的时间内就移动数秒。

This makes them Earth’s fastest invertebrates.

鱿鱼是地球上最快的无脊椎动物。

Some squid species have also developed unique adaptive behaviors.

一些品种的鱿鱼 还进化出了适应性行为。

The deep-sea vampire squid, when startled,

深海的吸血乌贼在受到惊吓后，

uses its webbed arms to make a cape it hides behind.

会用带蹼的触手 支出一个屏障让自己躲在后面。

The tiny bobtail, on the other hand, tosses sand over its body

微小的尾巴同时把 沙子扔在自己的身体上，

as it burrows away from prying eyes.

就像挖洞一样远离窥视的双眼。

The Pacific flying squid uses jet propulsion for another purpose:

太平洋褶柔鱼把 喷射推进用在其他用途：

to launch itself right out of the water.

把自己发射到水面之外。

Squids’ inventive adaptations have allowed them

鱿鱼那如同发明创造般的进化让他们

to proliferate for over 500 million years.

在超过 50 亿年的 时间里繁衍生息。

Even now, we’re still uncovering new species.

甚至现在，还有很多鱿鱼 是我们没有发现的。

And as we do,

就像我们做的那样，

we’re bound to discover even more about how these stealthy cephalopods

我们必然会发现更多有关 这些隐秘的头足类动物

have mastered survival in the deep and unforgiving sea.

是如何如大师般生活在无情深海中。

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