螳螂蝦在空中揮舞著有力的拳頭

螳螂蝦在空中揮舞著有力的拳頭

Mantis shrimps are famous for two things: perhaps the most extraordinary visual capacity of any animal, and the most powerful punch in the animal kingdom. Now a new twist has been placed on the second, with the discovery that mantis shrimps can only perform their extraordinary jabs underwater. In air, they limit themselves, probably lest they injure themselves.

螳螂蝦以兩樣?xùn)|西而聞名:也許是所有動(dòng)物中最非凡的視覺能力，以及動(dòng)物王國中最有力的拳頭?，F(xiàn)在，人們發(fā)現(xiàn)螳螂蝦只能在水下進(jìn)行特別的刺擊。在空中，它們限制自己，也許是為了避免傷害自己。

Mantis shrimps kill prey and fight off enemies using limbs known as maxillipeds that punch or spear targets. The speed of movement of these limbs is the fastest ever recorded for an animal. One mantis shrimp reportedly shattered the bulletproof glass of the aquarium in which he was housed.

螳螂蝦會(huì)殺死獵物，用上肢攻擊敵人。這些肢體的運(yùn)動(dòng)速度是有記錄以來動(dòng)物最快的。據(jù)報(bào)道，一只螳螂蝦打碎了他所在水族館的防彈玻璃。

The mantis shrimp punch is even more extraordinary when you consider it is conducted underwater, where viscous drag slows movements down. Dr Kathryn Feller of the University of Minnesota wondered how fast mantis shrimps would manage if this restriction was removed. Because scientists get to be cool sometimes she tested it by restraining seven shrimps of the species Squilla mantis in place and tickling their abdomens to induce punching. Because science can also be dangerous, Feller reported: “I have a pretty epic photo of my bleeding hand over a white sink when one stabbed me during this process,” in a background piece.

當(dāng)你考慮到螳螂捕蝦是在水下進(jìn)行的時(shí)候，那就更不尋常了，因?yàn)樗碌恼承宰枇?huì)減慢運(yùn)動(dòng)速度。明尼蘇達(dá)大學(xué)的博士Kathryn Feller想知道如果取消了這一限制，螳螂蝦能跑多快。因?yàn)榭茖W(xué)家們有時(shí)會(huì)覺得很酷，所以她測試了這個(gè)方法:在適當(dāng)?shù)牡胤揭种破咧贿@種蝦的螳螂，并在它們的腹部撓癢癢，讓它們出拳。因?yàn)榭茖W(xué)也可能是危險(xiǎn)的，F(xiàn)eller在一篇背景文章中寫道:“我有一張相當(dāng)壯觀的照片，我流血的手在一個(gè)白色的水槽上，在這個(gè)過程中被人刺傷了。”

The aquarium's water level was adjusted so the punches were thrown sometimes underwater and sometimes in air, but the subjects' gills were always safely beneath the waterline.

水族館的水位是可以調(diào)整的，所以拳頭有時(shí)扔在水下，有時(shí)扔在空中，但實(shí)驗(yàn)對象的鰓總是安全的在水線以下。

To her surprise, Feller found instead of relishing their new-found freedom, these tiny pugilists instead pulled their punches, moving at not much more than half the speed and unleashing a third the kinetic energy. On investigation, she concluded the shrimps deliberately limit their strike force in air.

令她驚訝的是，F(xiàn)eller發(fā)現(xiàn)這些小螳螂蝦們非但沒有享受到它們新獲得的自由，反而還在揮拳猛擊，它們的速度不到原來的一半，釋放出了三分之一的動(dòng)能。經(jīng)過調(diào)查，她得出結(jié)論，這些蝦是故意限制它們在空中的攻擊力量。

Stephen Luntz

Mantis shrimps achieve their remarkable punching power not with muscles, but with what are known as “spring-actuated systems”. Locusts and fleas use something very similar to leap into the air. Like an archer storing energy in a bow to be released very suddenly, the mantis shrimp's maxillipeds are latched into place before it uses its muscles to load energy in a spring, which then releases it far more rapidly than it was stored.

螳螂蝦出拳的力量不是靠肌肉，而是靠所謂的“彈簧驅(qū)動(dòng)系統(tǒng)”?；认x和跳蚤用一種非常類似的東西來跳躍到空中。就像弓箭手把能量儲(chǔ)存在弓里，然后突然釋放出來一樣，螳螂蝦的上頜骨在它用肌肉在彈簧中加載能量之前就被鎖住了，然后彈簧釋放能量的速度比儲(chǔ)存的要快得多。

Given that more powerful punches underwater don't seem to tire them out much, Feller thinks this modulation must reflect a risk that, if not dissipated by the water's drag, the mighty punch could harm the puncher as well as the target, perhaps through lack of a suitable braking mechanism. Locusts have a shock-absorbing material in their legs to prevent damage from excess kinetic energy; mantis shrimps are not known to have anything equivalent, so may have worked out long ago not to push too hard in air. “The animals don't give it the full pow so they don't blow out their joint,” Feller speculated.

考慮到在水下更有力的擊打似乎不會(huì)使它們疲勞，F(xiàn)eller認(rèn)為這種調(diào)節(jié)一定反映了這樣一種風(fēng)險(xiǎn)，如果不被水的阻力驅(qū)散，強(qiáng)大的擊打可能會(huì)傷害擊打者和目標(biāo)，也許是由于缺乏合適的剎車機(jī)制。蝗蟲的腿上有一種減震材料，可以防止動(dòng)能過剩造成的傷害;人們不知道螳螂蝦是否也有類似的東西，所以可能很久以前就知道不要在空氣中用力過猛。Feller推測說:“動(dòng)物們不會(huì)把整塊骨頭都掏出來，這樣就不會(huì)傷害關(guān)節(jié)。”

Feller notes in the Journal of Experimental Biology: “S. mantis strikes in air have a similar mass and performance to latch-mediated spring-actuated jumps in locusts, suggesting a potential threshold for the energetics of a 1-2 gram limb rotating in air.” In other words, mantis shrimps may be operating at the limits of what is biologically possible.

Feller在《實(shí)驗(yàn)生物學(xué)雜志》上寫道:“S。螳螂在空中的攻擊在質(zhì)量和性能上與蝗蟲的閉鎖彈簧驅(qū)動(dòng)的跳躍相似，這表明一個(gè)1-2克的肢體在空氣中旋轉(zhuǎn)的潛在閾值。換句話說，螳螂蝦可能已經(jīng)達(dá)到了生物學(xué)極限。

One disadvantage of spring-actuated systems is they happen so fast no animal's brains can stop, or even alter the movement, once it is engaged.

彈簧驅(qū)動(dòng)系統(tǒng)的一個(gè)缺點(diǎn)是，它們發(fā)生得太快了，動(dòng)物的大腦一旦被控制，就無法停止，甚至改變運(yùn)動(dòng)。