Flying snakes Slithering through the air

　　飛蛇 空中滑行

　　Fancy aerodynamics explain why some snakes are good gliders

　　奇特的氣體力學解釋了為什么一些蛇善于飛行

　　MANY animals have mastered the trick of gliding through the forest canopy. Flying frogsstretch the webbing between the toes of their enlarged feet. Some lizards spread elongatedribs covered in flaps of skin. And the colugo, a strange South-East Asian mammal, can travelas much as 70 metres between trees by spreading a membrane of skin thatconnects its limbs. Despite a lack of obvious body parts that can double up as a decent pairof wings, some snakes, too, can glide for remarkable distances.

　　許多動物掌握在林冠中滑行的技巧。青蛙在飛行時展開它的腳蹼;一些蜥蜴展開皮膚軟組織下的細長肋骨;猴貓，一種生長在東南亞的哺乳動物，通過伸展連接四肢的薄膜在樹中滑行多達70米。盡管身體明顯缺少一部分，如一對能夠拍打且適于滑行的翅膀，一些蛇也能飛行很遠。

　　To discover how snakes manage it Jake Socha of Virginia Tech and his colleagues conducted aseries of test flights with paradise tree snakes, a mildly venomous variety found in parts ofAsia. They launched the snakes from the top of a 15-metre tower and used four videocameras to construct 3-D images of the animals trajectories. The results, just published inBioinspiration and Biomimetics, show not only that flying snakes are surprisingly goodaviators but also that they employ some complex aerodynamic tricks.

　　為了查明蛇類如何成功的飛行很遠，維吉尼亞理工學院的Jake Socha和其同事用一些天堂樹蛇做了一系列的飛行試驗，這是一種毒性適中的蛇，它生長在亞洲部分地區。研究人員使樹蛇從15米高的塔頂端飛行，過程中使用了4個攝影機拍攝蛇滑行的軌跡，以拍攝成三維立體圖像。不久前在生物靈感和仿生學上發布的結果顯示：飛蛇的飛行不僅令人嘆為觀止，并且飛行過程中使用了一些在空氣動力方面的很復雜的技巧。

　　A paradise tree snake flattens its body into an aerofoil-like shape that can provide a degree oflift before it takes off from a branch by jumping upwards. It then falls at a steep angle andstarts undulating from side to side. As it gains speed its glide path becomes shallower,allowing it to cover a greater distance. The researchers found some snakes could glide for 24metres.

　　天堂樹蛇展平它的軀體，使其形成機翼般的形狀，這可以使它在借助樹干彈跳前產生一定的提升力。然后它急劇下降并且不停地擺動身體。隨著下降速度的增加，下滑道變得越來越淺，這使樹蛇滑翔很長一段路程。研究人員發現一些樹蛇可滑翔24米。

　　The 3-D analysis showed the snakes take up a staggered posture when gliding, with theirbodies angled upwards at about 25 to the oncoming air and their heads slightly higher thantheir tails. Dr Socha says this orientation seems to provide the creatures with anaerodynamic advantage. As a result of it, the wake of air forced backwards by onesegment of the snake s undulating body may provide extra lift to the segment behind in thesidewinding glide. Flying fish rely on a similar flow of accelerated air from their pectoral finsto provide lift to their smaller pelvic fins. Indeed, it is possible that the effect works bothways, and that rearward segments provide lift to those in front.

　　對三維立體圖像的分析表明：樹蛇滑翔過程中擺動著身體，軀體向上抬，與迎面的空氣呈25度角，頭部稍微高于尾部。Socha博士表示在空氣動力學角度上來講，這樣的身體趨向可能會對飛行的樹蛇產生推助的作用。這樣，擺動樹蛇的身體的前半部分擦過的空氣尾流可對側風滑行的后半部分起到提升的作用。同樣，飛魚借助胸鰭所產生的加速氣流，就可以對較小的腹鰭產生一定的提升作用。事實上，反過來也可能產生這種效果，即后半部分可為前半部分起到提升作用。

　　The snakes are also surprisingly manoeuverable and have been seen to turn in mid-air. Tofind out if this might be deliberate, Dr Socha limited their view from the tower so that theycould see only straight ahead when they launched themselves. Once airborne, and thus ableto observe trees to the side of their glide-paths, some of the snakes turned towards them.

　　樹蛇的飛行技巧也也令人嘆為觀止。人研究人員觀察到它們在飛行途中可以變向。為了探明樹蛇是否故意發出這一行為，Socha博士限制了樹蛇在飛行時的視野，目的是讓他們在起飛時只能向前看。一起飛，這些樹蛇就可以看到滑行路徑兩旁的樹，一些就轉變方向朝樹木飛去。

　　Dr Socha, who studies the relationship between form and function in animals, was partlyfunded in his snake research by America s Defence Advanced Research Projects Agency,which said it was interested in the science but obviously wonders about military applications.

　　研究動物的構成和功能的Socha 博士在對蛇進行研究時得到了美國國防發展研究項目的資助，它稱它對這部分科學很感興趣，但也明顯質疑是否可以將這部分科學應用到軍事領域。

　　Dr Socha does not expect to see snakelike drones in the skies soon. However, the ability toslither through holes, to swim and to climb trees and rocks, as well as to glide betweenelevated features of the landscape, is an attractive mixture for designers of roboticvehicles. The staggered-wing effect, in which the front of the body helps to provide lift for theback, may also be of interest to aircraft engineers. In the long term, then, the world sbattlefields may see machines that resemble some people s worst nightmares, slithering asthey do towards the enemy both on the ground and through the air.

　　Socha博士并未預期蛇形般的遙控飛機即將騰空出世，然而，設計集各種功能于一身的交通工具-全部自動化，能夠滑穿孔洞，穿行在水中，爬得大樹和巖石，滑行在凹凸不平的風景中-對于設計師來說，很具吸引力。擺動的雙翼所產生的效果-機身的前半部分可為后半部分增加提升力，對飛機工程師來說也可能頗感興趣。從長遠來看，在世界戰場可以看到那些出現在一些人的噩夢里的飛機，在陸地和空中滑翔，攻打敵人。

　　Flying snakes Slithering through the air

　　飛蛇 空中滑行

　　Fancy aerodynamics explain why some snakes are good gliders

　　奇特的氣體力學解釋了為什么一些蛇善于飛行

　　MANY animals have mastered the trick of gliding through the forest canopy. Flying frogsstretch the webbing between the toes of their enlarged feet. Some lizards spread elongatedribs covered in flaps of skin. And the colugo, a strange South-East Asian mammal, can travelas much as 70 metres between trees by spreading a membrane of skin thatconnects its limbs. Despite a lack of obvious body parts that can double up as a decent pairof wings, some snakes, too, can glide for remarkable distances.

　　許多動物掌握在林冠中滑行的技巧。青蛙在飛行時展開它的腳蹼;一些蜥蜴展開皮膚軟組織下的細長肋骨;猴貓，一種生長在東南亞的哺乳動物，通過伸展連接四肢的薄膜在樹中滑行多達70米。盡管身體明顯缺少一部分，如一對能夠拍打且適于滑行的翅膀，一些蛇也能飛行很遠。

　　To discover how snakes manage it Jake Socha of Virginia Tech and his colleagues conducted aseries of test flights with paradise tree snakes, a mildly venomous variety found in parts ofAsia. They launched the snakes from the top of a 15-metre tower and used four videocameras to construct 3-D images of the animals trajectories. The results, just published inBioinspiration and Biomimetics, show not only that flying snakes are surprisingly goodaviators but also that they employ some complex aerodynamic tricks.

　　為了查明蛇類如何成功的飛行很遠，維吉尼亞理工學院的Jake Socha和其同事用一些天堂樹蛇做了一系列的飛行試驗，這是一種毒性適中的蛇，它生長在亞洲部分地區。研究人員使樹蛇從15米高的塔頂端飛行，過程中使用了4個攝影機拍攝蛇滑行的軌跡，以拍攝成三維立體圖像。不久前在生物靈感和仿生學上發布的結果顯示：飛蛇的飛行不僅令人嘆為觀止，并且飛行過程中使用了一些在空氣動力方面的很復雜的技巧。

　　A paradise tree snake flattens its body into an aerofoil-like shape that can provide a degree oflift before it takes off from a branch by jumping upwards. It then falls at a steep angle andstarts undulating from side to side. As it gains speed its glide path becomes shallower,allowing it to cover a greater distance. The researchers found some snakes could glide for 24metres.

　　天堂樹蛇展平它的軀體，使其形成機翼般的形狀，這可以使它在借助樹干彈跳前產生一定的提升力。然后它急劇下降并且不停地擺動身體。隨著下降速度的增加，下滑道變得越來越淺，這使樹蛇滑翔很長一段路程。研究人員發現一些樹蛇可滑翔24米。

　　The 3-D analysis showed the snakes take up a staggered posture when gliding, with theirbodies angled upwards at about 25 to the oncoming air and their heads slightly higher thantheir tails. Dr Socha says this orientation seems to provide the creatures with anaerodynamic advantage. As a result of it, the wake of air forced backwards by onesegment of the snake s undulating body may provide extra lift to the segment behind in thesidewinding glide. Flying fish rely on a similar flow of accelerated air from their pectoral finsto provide lift to their smaller pelvic fins. Indeed, it is possible that the effect works bothways, and that rearward segments provide lift to those in front.

　　對三維立體圖像的分析表明：樹蛇滑翔過程中擺動著身體，軀體向上抬，與迎面的空氣呈25度角，頭部稍微高于尾部。Socha博士表示在空氣動力學角度上來講，這樣的身體趨向可能會對飛行的樹蛇產生推助的作用。這樣，擺動樹蛇的身體的前半部分擦過的空氣尾流可對側風滑行的后半部分起到提升的作用。同樣，飛魚借助胸鰭所產生的加速氣流，就可以對較小的腹鰭產生一定的提升作用。事實上，反過來也可能產生這種效果，即后半部分可為前半部分起到提升作用。

　　The snakes are also surprisingly manoeuverable and have been seen to turn in mid-air. Tofind out if this might be deliberate, Dr Socha limited their view from the tower so that theycould see only straight ahead when they launched themselves. Once airborne, and thus ableto observe trees to the side of their glide-paths, some of the snakes turned towards them.

　　樹蛇的飛行技巧也也令人嘆為觀止。人研究人員觀察到它們在飛行途中可以變向。為了探明樹蛇是否故意發出這一行為，Socha博士限制了樹蛇在飛行時的視野，目的是讓他們在起飛時只能向前看。一起飛，這些樹蛇就可以看到滑行路徑兩旁的樹，一些就轉變方向朝樹木飛去。

　　Dr Socha, who studies the relationship between form and function in animals, was partlyfunded in his snake research by America s Defence Advanced Research Projects Agency,which said it was interested in the science but obviously wonders about military applications.

　　研究動物的構成和功能的Socha 博士在對蛇進行研究時得到了美國國防發展研究項目的資助，它稱它對這部分科學很感興趣，但也明顯質疑是否可以將這部分科學應用到軍事領域。

　　Dr Socha does not expect to see snakelike drones in the skies soon. However, the ability toslither through holes, to swim and to climb trees and rocks, as well as to glide betweenelevated features of the landscape, is an attractive mixture for designers of roboticvehicles. The staggered-wing effect, in which the front of the body helps to provide lift for theback, may also be of interest to aircraft engineers. In the long term, then, the world sbattlefields may see machines that resemble some people s worst nightmares, slithering asthey do towards the enemy both on the ground and through the air.

　　Socha博士并未預期蛇形般的遙控飛機即將騰空出世，然而，設計集各種功能于一身的交通工具-全部自動化，能夠滑穿孔洞，穿行在水中，爬得大樹和巖石，滑行在凹凸不平的風景中-對于設計師來說，很具吸引力。擺動的雙翼所產生的效果-機身的前半部分可為后半部分增加提升力，對飛機工程師來說也可能頗感興趣。從長遠來看，在世界戰場可以看到那些出現在一些人的噩夢里的飛機，在陸地和空中滑翔，攻打敵人。