10種動物身體部位的另類用途(上)

Most animal appendages have obvious uses, but the evolutionary dice that dictate all adaptations sometimes land quite oddly. Old parts occasionally gain new and awesome utilities.

大多數動物身體的附屬部位都有顯而易見的用途，但是慢慢進化的身體部位爲了適應生存環境而變異出了奇特的功能，從而使原有的部位獲得了新的甚至是更神奇的功能。

es Use Their Ears And Eyes To Point And Communicate

10.馬兒們用它們的耳朵和眼睛來指路和交流

Horses are a lot more articulate than we thought. They communicate not only through snorts, brays, and neighs, but also with eyes and ears, the latter of which are highly pliable and used like equine turn signals.

馬兒比我們想象中更加善於表達自己。它們不僅通過擤鼻涕的聲音、模仿驢子的聲音和嘶叫來溝通，還通過眼睛和耳朵來交流，尤其是它們的耳朵非常柔軟靈活。在馬兒中，耳朵的用途就如同轉向燈在汽車中的用途一樣重要。

In a study, University of Sussex PhD student Jennifer Wathan and her adviser Karen McComb photographed horses looking at buckets of food. They then altered some of the images to obscure either the eyes or ears before scaling the photographs to life-sized proportions and showing them to real horses who were given a choice between two similar feed e looking at the unadulterated images, test horses tended to go for the same bucket as their facsimile compatriots. When the ears or eyes were obscured, this behavior disappeared. Of the two modifications to the images, the test subjects heeded the directions of the ears a bit more than the eyes. The study suggests that our wriggly-eared companions use these gesticulations to either point out food or to alert others to the presence of predatory animals. We probably would have figured this out sooner, but sometimes innate anthropocentric biases limit our scientific vantage point. Studies on animal linguistics often focus on gestures, postures, and calls because these are the main components of our language.

在一個研究中，蘇塞克斯大學的博士生詹妮弗和她的指導老師凱倫·麥庫姆拍到了馬兒們正在盯着幾桶食物看的照片。而後他們改變了一部分拍攝照片的內容，照片中的馬兒們有的被遮住眼睛來選擇不同的食物，有的是被遮住耳朵來選擇。隨後他們將照片調成和原物一樣的比例，再把這些照片給沒有遮住眼睛或耳朵的被測試的馬兒們看，讓它們在不同照片上的兩桶食物中進行選擇。被測試的馬兒們在看沒有修改過的照片時，傾向於和照片上的“同胞們”選擇其中同一個裝有食物的桶。當被測試的馬兒看到照片中被遮住眼睛或耳朵的“同胞們”時，這種同照片上“同胞們”選擇一致的行爲消失了。在兩次對原照片的改動當中，被測試的馬兒們更注重照片中的“同胞們”對於耳朵在食物選擇中所起的作用。研究發現，我們那些會擺耳朵的動物夥伴們，通過擺動它們的耳朵來指出食物所在，或警示兇猛食肉動物的出沒。我們也許很快就能發現其中的奧祕，但有時候我們人類固有的“人類中心說”制約了我們在科學探索方面的優勢。我們研究動物語言，經常關注它們的手勢、姿勢和呼叫聲，因爲這些是我們人類語言溝通的重要組成部分。

os Use Their Tails To Propel Feces

9.河馬用它們的尾巴來清掃糞便

With its dopey face, puffy body, and short, stubby tail, the hippopotamus is one of the animal kingdom's most deceptive killers. Among the most dangerous creatures on Earth, hippos lull victims into a false sense of security with pudgy cuteness and then strike with lightning reflexes and scimitar teeth.

擁有愚鈍的面龐，龐大的身軀，短而粗的尾巴，河馬是動物王國裏最能迷惑人的殺手。在世界上最兇猛的動物世界裏，河馬用自己笨重而可愛的身材讓獵物陷入“安全”的幻境，然後以出其不意的速度和尖利的牙齒來攻擊獵物。

But not everything about these animals is terrifying. Their tiny tails are hilarious not only in design but in function as well. You see, dominant male hippos mark their territory by scattering excrement, but they're too fat and lazy to walk around to do so. Instead, they twirl their little tails around like leathery propellers and defecate into the whirling so they spread their feces—mixed with a touch of urine for extra pungency—haphazardly in all directions to deter rival bulls from encroaching on their land. Oddly enough, juvenile hippos are inexplicably drawn to smelly dumps, and young are known to follow older males around to lick at their rear ends.

但並不是所有的關於河馬的描述都這麼恐怖。河馬小巧的尾巴不僅看着滑稽，用途也很有趣。你看，那些占主導地位的公河馬通過分散它們的糞便來劃定它們的領地界限，但是它們太懶了又那麼胖，不便走來走去清掃糞便。相反，它們快速旋轉它們的小尾巴，就像飛速旋轉的皮質螺旋槳那樣清除糞便。它們還將分散的糞便和尿液混合來製造刺鼻性氣味，隨意地從各個方向阻止它們的對手——公牛侵犯它們的領地。令人難以理解的是，小河馬卻對散發着惡臭的糞便異常着迷，也特別喜歡跟在年長公河馬後面舔舐它們的屁股。

-Jaw Ants Launch Themselves To Safety With Their Mandibles

8.大齒猛蟻可以利用自己的下頜“金蟬脫殼”

Trap-jaw ants have shears for mandibles and can snap them at 40 meters per second (90 mph). With such speed and size, they can easily cleave enemies in half in the blink of an eye. Amazingly, it turns out they can use their oversized jaws for defense as well as assault.

大齒猛蟻下頜的咬合力極強，其上下頜閉合速度可達40米/秒（90英里/時）。這種咬合速度及力度，眨眼間就能將敵人劈成兩段。神奇的是，它們的巨型下頜還是個“進可攻，退可守”的利器。

Researchers had noted that the ants would sometimes flick themselves into the air with their incredibly strong mandibles. It wasn't clear why—possibly as an evasive always, scientists tried to understand this puzzling behavior by reproducing it in the lab. They brought in some antlions, larger insects that love to eat ants. To capture their prey, antlions build pits in the sand that crumble beneath the unlucky ants' feet. Waiting inside the pit, the antlion gobbles up anyone that falls through. Sure enough, trap-jaw ants that were at risk of sinking into the sand sometimes used their mandibles to propel themselves away from danger. Furthermore, the ants that had their jaws glued together were only half as likely to escape their fate as dinner.

研究者們注意到，大齒猛蟻有時會利用它那壯碩無比的下頜把自己彈向高空。目前還沒有探明其原因——可能是一種逃生的戰略吧。如往常一樣，每當科學家們想要了解這些令人困惑的生物行爲時，他們就會在實驗室裏還原出這一行爲過程，以便觀察研究。他們帶回了一些蟻獅——體積更大且喜食螞蟻的昆蟲。爲了誘捕獵物，蟻獅會在沙土中設下陷阱，待某隻不走運的螞蟻失足落入陷阱，再把它大卸八塊，侵吞入腹。所有自投羅網的昆蟲都會被蟻獅吃掉。可以肯定的是，大齒猛蟻有時也會落入沙土陷阱，而它們的下頜則有助於幫其脫離險境。此外，當落入陷阱的大齒猛蟻的下顎被黏住時，它們僅有一半的機會能夠避免成爲其他生物的“盤中餐”。

ish Snouts Detect Electrical Fields

7.鋸鰩的吻鋸可以探測電場

The sawfish is a feared aquatic predator. Its large, serrated appendage makes for an intimidating weapon that can slice smaller fish clean in half. But the sawfish's multi-tool muzzle can also detect electrical fields produced by living creatures.

鋸鰩是一種令人生畏的水下“獵食者”。它有一件恐怖的殺傷性“武器”——龐大的鋸齒狀魚吻，可以將小一些的魚切割成兩半。它的多功能吻鋸還可以檢測出活體生物所產生的電場。

While dissecting a few sawfish specimens—that had died naturally—researchers found their fimbriated snouts were full of tiny pores. These were indicative of the animal's electrical prowess, and similar pores are present in other creatures that share this talent. These sensors are usually dotted around the mouth so that the fish can quickly clamp down on anything unlucky enough to trigger its might seem unfair that evolution gave a saw-faced beast what amounts to a video game mini-map, but it's a necessary tool when one lives in exceedingly murky waters where visibility is measured in millimeters if the sediment has been stirred. By using its saw as an electrical walking stick and rangefinder, the sawfish remains lethal where most would be blind.

通過解剖少數自然死亡的鋸鰩的樣本，研究者們發現它們的吻鋸鑲邊處長滿了微小的毛孔。這些代表着它接收到的來自其它動物的電場強度，其它擁有此項天賦的生物身上也會有與之相似的毛孔。這些傳感器分佈於魚吻四周，致使鋸鰩可以快速地通過電場位置判斷獵物的方位，進而給予這不走運的傢伙致命一擊。上天似乎很不公平地讓一個怪獸還進化出了帶鋸齒狀的臉部，這就如同在電視遊戲中加入了迷你地圖功能。但對於生活在深海——一旦有沉澱物被攪拌起來，可見度只能以毫米計算的渾水中的生物來說，這一“工具”是不可或缺的。有了此等“移動標杆”及“測距儀”，鋸鰩才能在大多數物種都看不清的情況下完成致命絕殺。

Use Their Antennae To Grip Tunnel Walls

6.螞蟻用觸角來抓着牆壁

Not long ago, researchers conducted one of the most detailed studies of ant tunneling ever. It's a common practice to fill a clear container or tube with dirt and watch the ants do their thing, but this time, X-ray tomography allowed researchers to watch the ants work under more natural conditions.

不久前，研究者們對螞蟻的隧道挖掘行爲進行了前所未有的詳細研究。這項研究通常的做法是，在透明的箱子或管道里裝上泥土，然後觀察螞蟻們如何巧奪天工。而這一次，由於採用X光斷層掃描，使研究者們能夠在更加天然的環境中觀察螞蟻工作了。

They found the tunnels were built to precise, optimal dimensions for structural integrity. To induce a mini-collapse (to observe how the poor ants cope and rebuild), scientists used a small piston to shoot a stream of air into the tunnel. To their amazement, the momentarily displaced ants latched onto the sides of the tunnel with their antennae, displaying an entirely novel use of the common turns out that the tunnels are not only built for strength, but small enough to allow the ants to catch themselves against the walls—quite a useful adaptation for busy little insects that spend considerable time traversing a vertical maze of tunnels.

研究者們發現，螞蟻的隧道在建築結構的完整性上，不僅精確而且尺寸大小絕佳。爲了觀察螞蟻們在隧道坍塌後如何應急和重建，科學家們用一個小活塞把一股氣流射進螞蟻的隧道里，以此引發一個小型坍塌。讓他們驚訝的是，那些在瞬間被吹飛的螞蟻們竟然用自己的觸角牢牢抓住隧道的牆壁，使這對作爲身體附肢的觸角有了一個全新的用途。研究結果顯示，螞蟻建造的隧道不僅僅很堅固，還因爲隧道夠小而讓它們掉落的時侯能從牆壁上穩住自己——對於這些整天在隧道的垂直迷宮裏來回穿梭忙碌的小昆蟲們而言，能夠用觸角抓住隧道牆壁確實是一個很有用的適應能力。

審校：齊墨 編輯：旭旭 來源：前十網