Name: 【TED-Ed】軟趴趴的烏賊是如何躲過或是擊退獵食者的？ (How squids outsmart their predators - Carly Anne York)
Uploaded: 2018-07-10T21:01:01.000Z
Duration: 5 min 13 s

In the ocean's depths, two titans wage battle: the sperm whale and the colossal squid.

在海底深處，兩隻巨獸正要開戰，分別是抹香鯨和大王烏賊。

Sperm whales use echolocation to hunt these squid for food, but even against this gigantic animal, squid can put up an impressive fight.

抹香鯨藉由回聲定位獵食這些烏賊，但即使對手是如此龐然大物，烏賊也能打出令人印象深刻的一戰。

Scientists know this because on the bodies of washed-up whales, they frequently find huge, round suction scars, emblazoned there by large, grasping tentacles.

透過沖上岸的鯨魚屍體，科學家得知這件事實，他們經常在鯨魚屍體上找到巨大圓形的吸吮疤痕，這些疤痕是由巨大的抓握式觸手所紋印。

Ranging in size from this giant's impressive 14 meters to the 2.5 centimeters of the southern pygmy squid, these creatures fall into the group of animals known as cephalopods.

這些生物尺寸範圍廣泛，大至令人印象深刻的 14 公尺，如這隻巨獸，或小至 2.5 公分長的南方侏儒烏賊，他們被歸類為頭足類動物。

There are about 500 squid species worldwide, and they live in all the world's oceans, making them a reliable food source for whales, dolphins, sharks, seabirds, fish, and even other squid.

全世界大約有 500 種烏賊品種，遍及全球海洋，也使得他們成為許多動物的可靠食物來源，如鯨魚、海豚、鯊魚、海鳥、魚類，甚至是其他烏賊

Indeed, squid themselves are fearsome ocean predators.

沒錯，烏賊本身就是一種可畏的海洋獵食者。

But their most extraordinary adaptations are those that have evolved to help them thwart their predators.

但他們最非凡的在於那些演化來幫助他們躲過獵食者的適應能力。

Squid, which can be found mainly in estuarine, deep-sea, and open-water habitats, often swim together in shoals.

烏賊主要棲息在河口、深海和開放水域，他們通常會成群游行。

Being out in the open without anywhere to hide makes them vulnerable, so as a first line of defense, they rely on large, well-developed eyes.

在開放、無藏躲處的區域出沒，使得他們容易遭受攻擊，所以做為第一線防護，他們仰賴巨大、演化良好的眼睛。

In the colossal squid, these are the size of dinner plates, the largest known eyes in the animal kingdom.

大王魷魚擁有相當於晚餐盤大小的眼睛，是動物世界已知最大的眼睛。

When it's dark or the water is murky, however, squid rely on a secondary sensory system, made from thousands of tiny hair cells that are only about twelve microns long and run along their heads and arms.

然而，當水域黑暗或是混濁時，烏賊會仰賴次要的知覺系統，那是佈滿在他們頭部和觸角上的成千個細小毛髮細胞，細胞尺寸才只有 12 微米長。

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

每個毛髮細胞都與神經系統的軸突連接。

Swimming animals create a wake, so when the hairs on the squid's body detect this motion, they send a signal to the brain, which helps it determine the direction of the water's flow.

動物游泳時會留下行經痕跡，所以當烏賊身上的毛髮偵測到這些痕跡，他們會傳遞訊息到大腦，幫助大腦判定水流方向。

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

如此一來就算是在最黝暗的水裡，烏賊也能感知到靠近的獵食者。

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

因著這個威脅，烏賊採取措施將自己隱身，不被獵食者發覺。

Squid skin contains thousands of tiny organs called chromatophores, each made of black, brown, red or yellow pigments and ringed in muscle.

烏賊皮膚含有上千個微小器官，稱為色素體，每個色素體都由黑色、棕色、紅色和黃色色素所組成，並且環繞於肌肉中。

Reflecting cells beneath the chromatophores mirror the squid's surroundings, enabling it to blend in.

在色素體底下的反射細胞映照出烏賊身處的環境，使得烏賊融於環境。

So, when the muscles contract, the color of the pigment is exposed, whereas when the muscles relax the colors are hidden.

所以當肌肉收縮時，色素顏色就會顯露出來，而當肌肉鬆弛時，顏色會隱藏。

Each of these chromatophores is under the individual control of the squid's nervous system, so while some expand, others remain contracted.

每一個色素體都由烏賊的神經系統個別操作，所以當有些擴張時，有些則收縮。

That enables countershading, where the underside of the squid is lighter than the top, to eliminate a silhouette that a predator might spy from below.

這也使得烏賊能夠反蔭蔽，也就是當烏賊身體底部顏色淺於上部時，就能去除輪廓，讓底下潛藏的獵食者看不到。

Some predators, however, like the whales and dolphins, get around this ruse by using sound waves to detect a squid's camouflaged form.

然而有些獵食者如鯨魚和海豚，會利用聲波破除這套伎倆，偵測出烏賊的隱形形體。

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

但是烏賊不甘示弱，他還藏有兩招策略。

The first involves ink, produced inside its mantle.

第一招是利用墨水，由他的罩頭內部生產。

Squid ink is made mostly of mucus and melanin, which produces its dark coloring.

烏賊墨水主要由黏液和黑色素組成，所以顏色才會如此黑。

When squid eject the ink, they either use it to make a large smokescreen that completely blocks the predator's view or a blob that roughly mimics the size and shape of the squid.

當烏賊射出墨水，要嘛是為了製造大型黑幕，完全阻絕獵食者的視野，不然就是為了形成一個斑紋，形似烏賊的尺寸及身形。

This creates a phantom form, called a pseudomorph, that tricks the predator into thinking it's the real squid.

這樣就能創造出一個幻影，稱為偽形，哄騙獵食者，讓他們以為那是真的烏賊。

As a final touch, squid rely on jet propulsion to rapidly shoot away from their hunters, reaching speeds of up to 25 miles per hour and moving meters away in mere seconds.

最為壓軸好技，烏賊依賴的是噴射推進力，讓他們能夠飛快地噴射遠離獵食者，時速趨近於每小時 40 公里，短短幾秒內就能移動數公尺。

This makes them Earth's fastest invertebrates.

這也使得他們成為地球上最快速的無脊椎動物。

Some squid species have also developed unique adaptive behaviors.

有些烏賊品種也發展出獨特的適應行為。

The deep-sea vampire squid, when startled, uses its webbed arms to make a cape it hides behind.

深海吸血鬼烏賊受驚嚇時，會利用他蹼狀的手臂做出一頂斗篷，用以躲藏。

The tiny bobtail, on the other hand, tosses sand over its body as it burrows away from prying eyes.

小小的截尾烏賊則是會用沙子覆蓋自己的身體，以便躲過獵食者的眼睛。

The Pacific flying squid uses jet propulsion for another purpose: to launch itself right out of the water.

大西洋飛行烏賊把噴射推進應用在別的用途上，那就是將自己射出水面。

Squids' inventive adaptations have allowed them to proliferate for over 500 million years.

烏賊創意多元的適應方式使得他們得以繁衍超過 5 億年。

Even now, we're still uncovering new species.

直到今日，我們還在發掘新的品種。

And as we do, we're bound to discover even more about how these stealthy cephalopods have mastered survival in the deep and unforgiving sea.

與此同時，我們會知道更多這些神秘的頭足類動物在無情深海中生存下來的方式。