“蛇爲什麼沒有腳”真相大白

The Mystery Of Why Crafty Snakes Shed Their Legs Is Finally Solved

“蛇爲什麼沒有腳”真相大白

Mention snakes and the image that comes to mind is that of a stealthily gliding reptile. Turns out that this was not always the case. Ancient snake fossils indicate that the reptiles once had legs, just like the rest of us. So why did snakes decide to shed them in favor of the slither that sends chills down our spines? That is a mystery researchers have been trying to solve for some time.

一提到蛇，大家就會想起它神出鬼沒快速爬行的樣子。事實證明，它並非一直如此行進。古代蛇類化石證明，它曾經和人類一樣是有腳的。那爲什麼蛇會放棄進化它的腳，用如此讓人毛骨悚然的方式爬行呢？科學家們一直在努力調查其中的奧祕。

There are currently two schools of thought. Some scientists believe that the reptiles dispensed with their legs to enable them to dwell in water. Others think that the reptiles evolved from burrowing lizards and shed their limbs over time, as they stretched and became longer.

對此，現在主要有兩種假說。有些科學家認爲蛇放棄進化自己的腳是爲了更好的在水中生存。另一些科學家則認爲蛇是由穴居蜥蜴進化而來的，它們慢慢伸展變長，逐漸放棄了自己的腳。

The first proof that the second theory is more likely came in July 2015. David Martill paleobiologist at the University of Portsmouth was leading a field trip at Germany's Museum Solnhofen when he stumbled upon a rare fossil of a four-legged snake that inhabited the planet 113-million years ago.

第二種假說的證據是在2015年7月發現的。Portsmouth大學的古生物學家David Martill在德國Solnhofen博物館帶隊考察時，無意間看到了大約生活在1.13億以前的稀有四腳蛇化石。

Now a new study conducted by a group of Scottish and American scientists further validates that snakes probably ditched their legs to slither through underground burrows, allowing them to avoid predators and pounce upon unsuspecting prey.

最近，蘇格蘭和美國科學家聯手進行的一項新研究進一步證明了蛇也許是爲更靈活的在地下洞穴穿梭，躲避捕食者突如其來的襲擊，才放棄進化自己的腳。

The team led by Hongyu Yi at Edinburgh’s School of GeoSciences reached the conclusion after studying a 90 million-year-old skull of the Dinilysia patagonica an ancient reptile that is closely related to the modern-day snake. The discovery was possible thanks to new CT scan technology that allowed them to create 3D models of the skull and compare them to that of modern snakes and lizards.

愛丁堡地學院Hongyu Yi帶領的團隊，通過研究的一塊被稱爲Dinilysia patagonica的古代爬行生物頭骨才得出了結論。這種生物與當代蛇類有很大關聯，大概存在於9億年前。新的CT掃描技術使他們能夠創建頭骨的3D模型來與現代的蛇類和蜥蜴作比較，才得出此發現。

The researchers were looking to see if the reptiles shared the same unique ear structure that is found in burrowing animals. Sure enough, though the ear canals and cavities have adapted further in modern-day burrowing snakes and lizards, there remains a substantial similarity. Snakes that currently live in water or above ground do not have the same adaptations.

研究者想查眀這種爬行生物是否與穴居動物有一樣的耳部結構。可以確定的是，雖然今天的穴居蛇類和蜥蜴的耳道和耳腔已有很大的改變，它們之間還是存在着某種潛在相似性。而生活在水中和陸地上的蛇類卻沒有這樣的改變。

The evidence was enough for the scientists who published their findings in the online journal Science, to conclude that snakes had evolved on land. They believe that as the reptile's hearing sharpened and became accustomed to their subterranean habitat, its limbs began to recede, until they disappeared altogether.

此研究結果，足以讓科學家在在線科學期刊上公佈“曾經的水生蛇類有些進化上岸”這一發現。他們認爲，爬行生物隨着聽覺的進化，慢慢適應陸地上的生存環境，它們的腳就也隨之慢慢蛻化，直至消失。

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