鳥蛋

胡楊

Scientists believe they know why birds eggs are in different shapes. Some eggs are quite round； some are kind of potato-shaped； and others are longer and pointy1. Two thousand years ago， the Greek philosopher Aristotle said flatter2 eggs had female chicks inside them and rounder eggs contained male chicks. But he was wrong. A new study from Princeton University in the USA suggests that the shape of the egg depends on how well and how fast the female bird flies. Professor Mary Stoddard said， “It has not gone unnoticed that birds have evolved to（lay eggs with） shapes that are quite different in form—everything from a spherical3 owl4 egg to a pointy sandpiper5 egg.”

科學(xué)家相信他們知道了為什么鳥類的蛋形狀不同。有些蛋是圓形的，有些是馬鈴薯形的，有些是長而尖的。兩千年前，希臘哲學(xué)家亞里士多德說過，形狀扁一些的鳥蛋可以孵化出雌性小鳥，而圓些的蛋則一般孵化出雄性小鳥。但是他錯了。美國普林斯頓大學(xué)的一項(xiàng)新研究表明，鳥蛋的形狀取決于雌鳥飛行的能力和速度?，旣悺に雇羞_(dá)德教授說：“人類還是注意到了，鳥類下的蛋進(jìn)化出了各種各樣不同的形狀，從球形的貓頭鷹蛋到尖尖的鷸鳥蛋?！?/p>

Professor Stoddard and her colleagues created a mathematical6 formula7 to map the shape of different eggs. They looked at almost 50，000 eggs from 1，400 different bird species. The researchers put the shape， length and height of the eggs into a computer database. They also looked at how oval8 the eggs were. The researchers found that the birds that laid the most-oval-shaped eggs were the best fliers9. Professor Stoddard said： “We were shocked to see that one of the best explanations for egg shape variation was flight ability.” The researchers found that hummingbirds10 and sandpipers laid the most-oval-shaped eggs； owls laid the roundest eggs； and sea birds laid the pointiest eggs.

斯托達(dá)德教授和她的同事們創(chuàng)建了一個數(shù)學(xué)公式來繪制不同的蛋的形狀。他們觀察了來自1400種不同的鳥類的近5萬個蛋。研究人員將蛋的形狀、長度和高度輸入計算機(jī)數(shù)據(jù)庫中。他們還研究了蛋的卵形。研究人員發(fā)現(xiàn)，那些飛行能力最強(qiáng)的鳥類產(chǎn)出來的蛋最為橢圓。斯托達(dá)德教授說：“我們很震驚地發(fā)現(xiàn)，最能解釋蛋形變化的因素之一居然是不同的鳥的飛行能力?！毖芯咳藛T發(fā)現(xiàn)，蜂鳥和鷸鳥的蛋最為橢圓；貓頭鷹的蛋則是最圓的蛋；海鳥產(chǎn)的蛋則是最尖的蛋。endprint