鸟蛋

胡杨

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.”

科学家相信他们知道了为什么鸟类的蛋形状不同。有些蛋是圆形的，有些是马铃薯形的，有些是长而尖的。两千年前，希腊哲学家亚里士多德说过，形状扁一些的鸟蛋可以孵化出雌性小鸟，而圆些的蛋则一般孵化出雄性小鸟。但是他错了。美国普林斯顿大学的一项新研究表明，鸟蛋的形状取决于雌鸟飞行的能力和速度。玛丽·斯托达德教授说：“人类还是注意到了，鸟类下的蛋进化出了各种各样不同的形状，从球形的猫头鹰蛋到尖尖的鹬鸟蛋。”

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.

斯托達德教授和她的同事们创建了一个数学公式来绘制不同的蛋的形状。他们观察了来自1400种不同的鸟类的近5万个蛋。研究人员将蛋的形状、长度和高度输入计算机数据库中。他们还研究了蛋的卵形。研究人员发现，那些飞行能力最强的鸟类产出来的蛋最为椭圆。斯托达德教授说：“我们很震惊地发现，最能解释蛋形变化的因素之一居然是不同的鸟的飞行能力。”研究人员发现，蜂鸟和鹬鸟的蛋最为椭圆；猫头鹰的蛋则是最圆的蛋；海鸟产的蛋则是最尖的蛋。endprint