Is it a fuzzy sock? An overripe banana? A moldy tube of toothpaste?

是絨毛襪？過熟的香蕉？還是發霉的牙膏管？

In fact, this is the humble sea cucumber, and while it might look odd, its daily toil paves the way for entire ecosystems to thrive.

事實上，這是一隻小海參。雖然牠看起來很奇怪，但牠卻每天忙著為整個生態系統的繁盛舖路。

Sea cucumbers are members of the 'phylum Echinodermata,' along with sea urchins, starfish and other radially symmetrical, "spiny-skinned" marine invertebrates.

海參屬於棘皮動物門，其他棘皮動物包括海膽、海星及其他放射狀對稱且體表多刺海洋無脊椎動物。

Some sea cucumbers have feathery tentacles flowing from their mouths.

有些海參有從嘴巴伸出來的羽狀觸手。

Some are puffed like bloated balloons.

有些則像膨脹的氣球一樣。

And others simply look like Headless Chicken Monsters: the actual name given to a rare deep-sea species.

還有些看起來就像無頭雞怪：真的有一種稀有深海海參以此為名。

But they are generally characterized by their long, cylindrical shape.

但牠們通常是長長的圓柱型。

A sea cucumber is essentially a brainless, fleshy form surrounding a digestive tract, bookended by a mouth and an anus.

海參本質上是環繞消化道的無腦肉質結構，兩端分別是嘴巴和肛門。

Adhesive tube feet run the length of their bodies and allow them to scoot along the seafloor.

海參從頭到腳有很黏的管足，讓牠們能在海底疾走。

Specialized tube feet can be used for feeding and respiration, though many sea cucumbers actually breathe through their anuses.

牠們特殊的管足能用來取食和呼吸，不過許多海參其實是透過肛門來呼吸。

Rhythmically contracting and relaxing their muscles, they draw water in and out over an internal lung-like structure called a respiratory tree that extracts oxygen from seawater.

透過有節奏地收縮和放鬆肌肉，牠們將水吸入體內叫做呼吸樹，類似肺的構造中後排出，並藉此能從海水粹取出氧氣。

Certain species of crabs and pearlfish take advantage of this rhythmic action and, once the sea cucumber's anus is dilated, they shimmy in and take shelter.

某幾類螃蟹和隱魚會利用這種有節奏的動作，在海參的肛門擴大的時候，搖擺而進以尋求掩蔽。

The rear end of a single sea cucumber can harbor up to fifteen pearlfish at a time.

一隻海參的後段一次可以容納高達十五隻隱魚。

However, it seems that not all sea cucumbers put up with this intrusive behavior.

然而，似乎並非所有海參都能容忍這種侵入行為。

Some species are equipped with five teeth around their anus, suggesting that they may have taken an evolutionary stand against unwanted guests.

有幾種海參在肛門周圍有五顆牙齒，這意味著牠們可能為了對抗不速之客而產生了演化。

But even sea cucumbers that lack anal teeth are outfitted with tools to defend themselves.

但就連沒有肛門牙齒的海參也配有可以自我防禦的工具。

They evade threats and launch counter-attacks using their mutable collagenous tissue, or MCT.

牠們用來躲避威脅和反擊的工具是可變膠原組織 (MCT)。

This gel-like tissue contains bundles of collagen, called “fibrils.”

這種如膠質般的組織內有大量稱為「纖維絲」的膠原。

Proteins can interact with these fibrils to slide them together, stiffening the tissue, or apart, softening it.

蛋白質能和這些纖維絲作用，使其更緊密、組織硬化；或使其疏離、組織柔軟。

This versatile tissue has many advantages: it aids in efficient locomotion; enables sea cucumbers to fit into small spaces; and allows them to reproduce asexually by splitting apart.

這種多功能的組織有許多好處。它能協助海參有效率的移動， 讓牠能塞得進狹小空間； 並讓牠們能夠透過分裂進行無性生殖。

But MCT's most explosive application is employed when a predator attacks.

但 MCT 最令人震撼的應用方法其實是在海參被捕食者襲擊的時候。

By loosening the attachments of internal tissues then quickly softening and contracting their muscles, many species are capable of shooting a wide range of organs out of their anuses.

數種海參能夠鬆開附著的內部組織，快速軟化和收縮肌肉，將許多器官從肛門射出。

This act is called "evisceration", and it's a surprisingly effective defense mechanism.

這個動作稱為「捨棄內臟」，是種效果驚人的防禦機制。

In addition to startling and distracting predators, the innards of some sea cucumber species are sticky and toxic.

除了會讓捕食者受到驚嚇並分心之外，有幾種海參的內臟很黏且具有毒性。

Evisceration may seem drastic, but sea cucumbers are able to regenerate what they've lost to their gut reaction in just a few weeks' time.

捨棄內臟的作法似乎很極端，但海參只需要幾週的時間，就能將射出的內臟再生。

Aside from the few species that have evolved to swim and those that feed without moving, many of these cumbersome creatures pass their time grazing the seabed.

除了演化成會游泳，和不移動就能進食的極少數海參以外，這種笨重的生物大多的時間都在海底吃草。

Sea cucumbers are found everywhere from shallow shores to abyssal trenches 6,000 meters below sea level.

海參無所不在，從淺海岸到海面下六千公尺深的海溝都有牠們的蹤跡。

On the deep seafloor, they comprise the majority of animal biomass, reaching up to 95% in some areas.

在深海海底，他們佔了生物量的絕大多數，在某些地區比例高達 95%。

As these sausage-shaped wonders trudge along, they vacuum up sand, digest the organic matter it contains, and excrete the byproduct.

當這些香腸型狀的奇觀跋涉時，牠們會吸起沙子，將沙中有機物質消化掉後排泄出副產品。

In this process, sea cucumbers clean and oxygenate the seafloor by breaking down detritus and recycling nutrients.

在這個過程中，海參會分解碎石，將營養物回收，清理海底並為海底充氧。

This creates the conditions for sea grass beds and shellfish to thrive.

如此一來便為海草床及殼類水生動物創造出適宜生長的條件。

Sea cucumber excretions can also aid in coral formation and may play a role in buffering marine environments from ocean acidification.

海參的排泄物也能協助珊瑚形成，且可能也為海洋環境扮演緩衝海洋酸化的角色。

As the ocean's vacuum cleaners, they are very good at their job: about half of the sandy seafloor is thought to have passed through the digestive tract of a sea cucumber.

身為海洋的清潔者，牠們非常擅長自己的工作；一般認為有大約一半的海底沙地曾經經過海參的消化道。

So next time you're rejoicing in the feeling of sand crunching between your toes, consider this: those very grains of sand might have, at one point or another, been excreted by a pickle that breathes through its butt.

所以，下次當你在享受沙子從腳趾間經過的感受時，別忘了，那些沙粒可能在某個時點曾被這種用屁股呼吸的醬瓜型生物給排泄出來過。

If you're looking for more strange creatures who call this planet home, don't miss this video about naked mole rats: cold-blooded mammals with metabolism of plants.

如果你還想了解更多與我們同樣以這個星球為家的奇妙生物的話，千萬別錯過這個有關裸鼴鼠的影片：牠是一種冷血哺乳類動物，還具有植物般的代謝率。

Or perhaps you'd like to know more about the octopus, whose entire body is a brain!

或者你可能想了解更多有關章魚的事情：牠的整個身體都是大腦！