听力文摘：蛇的视力

SnakeVision

蛇的视力

Snakes have heat-vision that allows them to catch their dinners in the dark. True or false?

蛇靠着它们的“热视力”能力来在夜晚捕捉猎物。是对还是错？

True! It isn’t quite right to call it “vision,” though–more accurate would be to say that certain species, such as rattlers, have pits just under their eyes that contain specialized¹ heat-sensing organs.

答案当然是正确的！但是把蛇的这种能力说成是“视力”好像不是很准确。更准确地说，应该是某些蛇类，如响尾蛇，在它们眼睛的下面部位有专门的呈凹陷状的热感应器官——颊窝。

This ability to spot heat comes in handy in the desert, especially if you’re out looking for a quick-moving mouse to make into a snack and there isn’t enough light to see by. Rattlers are amazingly good at catching² prey³ because of their heat-seeking ability.

在沙漠当中，蛇的这一能力可谓是方便之极。特别是当蛇在周围光线不足的情况下，想要抓只小老鼠当点心的时候，更能体现其方便之处。响尾蛇是响当当的捕猎好手，当然，这基本上是得益于它的热感应能力。

New studies have actually shown that the same sense organs are used for seeking cold as well. This is just as important when you live in a desert; overheating is always a possibility. Two researchers at Indiana State University in Terre Haute found this out by covering some rattlers’ facial pits with little plastic balls temporarily glued in place.

新的研究表明，颊窝还可以用来做冷感应器。生活在沙漠中，找出较凉爽的地方也是很重要的；毕竟，在沙漠中过热现象是家常便饭。两名印第安纳州立大学的研究人员在Terre Haute得出了这一结论。他们暂时用胶水把塑料小球固定在一些响尾蛇的颊窝上，以此将它们的颊窝堵住。

With these organsblocked, the rattlers were no better at finding the cool spot in a maze⁴ than if they had been moving around by chance. They were “cool-blind.” Take the balls out and the rattlers quickly found their way to the cooler spot. Their thermal⁵ vision, so to speak, had been restored.

在颊窝被堵住的情况下，响尾蛇便无法从一个迷宫中找出“温度较低的地方”，相比，它只会在四处乱转。此时此刻的它们是“冷盲”。取出小塑料球，响尾蛇便能迅速地找出较冷的地方。也可以说是，他们的热视力已经恢复了。

Now researchers debate this, but it’s possible that the ability to find a cool spot in a desert actually came first, in terms of evolutionary⁶ history. Get that, and the ability to snag a hot mouse might come as a tasty bonus.

目前，科学家们正就此展开讨论。但是，从演化历史来看，凭借这一能力在沙漠中找到一个较凉爽的地方确实是至关重要的。满足这一点之后，再靠热感应能力去抓一只活生生的老鼠也算是美味的奖励啦。

1 specialized   

adj.专门的，专业化的

参考例句：

• There are many specialized agencies in the United Nations.联合国有许多专门机构。
• These tools are very specialized.这些是专用工具。

2 catching   

adj.易传染的，有魅力的，迷人的，接住

参考例句：

• There are those who think eczema is catching.有人就是认为湿疹会传染。
• Enthusiasm is very catching.热情非常富有感染力。

3 prey   

n.被掠食者，牺牲者，掠食；v.捕食，掠夺，折磨

参考例句：

• Stronger animals prey on weaker ones.弱肉强食。
• The lion was hunting for its prey.狮子在寻找猎物。

4 maze   

n.迷宫，八阵图，混乱，迷惑

参考例句：

• He found his way through the complex maze of corridors.他穿过了迷宮一样的走廊。
• She was lost in the maze for several hours.一连几小时，她的头脑处于一片糊涂状态。

5 thermal   

adj.热的，由热造成的；保暖的

参考例句：

• They will build another thermal power station.他们要另外建一座热能发电站。
• Volcanic activity has created thermal springs and boiling mud pools.火山活动产生了温泉和沸腾的泥浆池。

6 evolutionary   

adj.进化的；演化的，演变的；[生]进化论的

参考例句：

• Life has its own evolutionary process.生命有其自身的进化过程。
• These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。