幾百年來，人們一直習慣用「鱷魚的眼淚」來比喻虛假的同情和偽裝的悔過，為什麼鱷魚的眼淚就是虛偽的呢？鱷魚真的會在進食的時候為口中的獵物哭泣嗎？來看科學家為你解密。
If someone is crying in an attempt to fake remorse or empathy, we say they are shedding 「crocodile tears.」 But how and why did we start pegging insincere displays of emotion to the toothy reptiles?如果某人哭泣是為了裝出悔過或同情的樣子，我們就說他們掉的是「鱷魚的眼淚」。但是我們是怎樣又是為何會把不真誠的感情流露和鱷魚聯繫在一起的呢？
The origin may have become popular around the 14th century when a bestselling memoir, The Voyage and Travel of Sir John Mandeville, referenced serpents who sob while eating their human victims.這個說法大約是在14世紀開始流行起來的，當時有一本暢銷的回憶錄叫《約翰·曼德維爾爵士的航海旅行》，裡面提到蛇在吃人的時候會流淚。
In the centuries since, crying crocodiles have become a metaphor for superficial remorse. The expression has been used as a fable to teach sincere repentance, by Shakespeare to convey false grief, and, more recently, by media mocking tearful politicians or murder suspects.從那以後的數個世紀以來，哭泣的鱷魚便被用來比喻虛偽的悔恨。這個表達曾作為寓言用來告誡人們要真心悔悟，也曾被莎士比亞用來指代假意的悲傷，到了現代，則被媒體用於嘲諷流淚的政客或謀殺嫌疑犯。
In 2007, University of Florida zoologist Kent Vliet actually proved that the animals do sob while snacking. But because crocodiles eat while in the water—making a study of their meal-time tears difficult—he studied their close relatives, caimans and alligators, who might dine on dry land. Out of the seven he filmed eating at a Florida alligator park, five teared up before, during, and after eating.2007年，佛羅裡達大學的動物學家肯特·弗利特證明了動物在進食的時候確實會哭泣。但因為鱷魚是在水中進食的，研究它們進食期間是否會落淚比較困難，所以弗利特就研究了鱷魚的近親凱門鱷和短吻鱷，它們會在旱地上進食。他在佛羅裡達短吻鱷公園拍攝的七隻鱷魚中，有五隻在進食前、進食期間或進食後都會流淚。
Vliet's theory is that when the animals enthusiastically smack their jaws, the movement forces air through the crocodiles』 sinuses and ultimately empties tears into their eyes. Their eyes not only water but can froth and bubble, as Vliet witnessed at the alligator park, where some even teared up in anticipation of their meal of chicks, quail, and feed biscuits.弗利特的理論是，當動物用力地咀嚼食物時，咀嚼的動作會迫使空氣流經鼻竇，從而讓眼淚湧出來。據弗利特在短吻鱷公園親眼目睹，它們的眼睛不但會流淚，還會冒出泡沫，一些鱷魚甚至在準備吃雞、鵪鶉和餅乾的時候就流下了眼淚。
Vliet was asked to investigate the biology behind the 「crocodilian metaphor」 by Malcolm Shaner, a UCLA neurologist researching a phenomenon in which some facial palsy sufferers cry when they chew. Doctors often refer to this eye-watering condition as 「crocodile tears,」 and a 1920s Russian scientist once suggested that such weakened facial muscles allowed "older, possibly crocodilian neurological pathways to emerge" in humans.弗利特是受加州大學洛杉磯分校的神經學家馬爾科姆·沙納之託來研究「鱷魚比喻」背後的生物學原理。沙納正在研究某些面癱患者在咀嚼時會流淚的現象。醫生們通常把這種流淚症狀稱為「鱷魚的眼淚」。20世紀20年代的一位俄羅斯科學家曾指出，這種面部肌肉衰弱可能導致人體起用「更古老的或許是鱷魚式的神經通路」。
由此看來，鱷魚流淚只是進食時身體產生的一種自然生理現象，和同情悔過毫無關係，難怪人們會將虛偽的哭泣比作鱷魚的眼淚了。