科学美国人60秒 SSS 蟋蟀什么都没做 却可以避免被蝙蝠吃掉

This is Scientific American's 60-second Science, I'm Emily Schwing.

这里是科学美国人——60秒科学系列，我是埃米莉·施温。

"So what you're listening to now, that's a recording¹ from the rain forest."

“现在你听到的是来自雨林的录音。”

That's Marc Holderied of the University of Bristol in the U.K.

英国布里斯托大学的马克·霍尔德里德说到。

He specializes in bioacoustics: how animals produce sound and communicate with the sounds they make.

他专门研究生物声学：动物如何发出声音并利用声音交流。

In the recording you just listened to, Holderied removed the sounds we humans can hear

在刚才听到的录音中，霍尔德里德删除了人类能听到的声音，

and reduced the frequencies of the sounds we normally wouldn't hear so that they're audible to our ears.

并降低了我们通常听不到的声音的频率，以便我们能听到这些声音。

"A rain forest is a very noisy environment. There's insect sounds, bird sounds; there's leaves rustling².

“雨林是非常嘈杂的环境。有昆虫叫声，鸟鸣声和树叶沙沙作响的声音。

And all of this makes it harder for you to detect something you want to hear."

所有这些都使我们更难发现我们想听到的声音。”

Holderied is particularly interested in sounds from the ultrasonic³ range—these are frequencies our ears can't detect.

霍尔德里德对超声波范围的声音特别感兴趣，而这些频率我们的耳朵无法探测到。

But they come in loud and clear for a sword-tailed cricket in Panama. Here's their home, slowed down so we can hear it.

但对巴拿马剑尾蟋蟀来说，这些声音会响亮且清晰地出现。这是它们的栖息地，声音频率被降低，因此我们能听到。

Holderied and colleagues at the Universities of Bristol and Graz in Austria,

霍尔德里德和他在奥地利布里斯托尔大学以及格拉兹大学的同事最近发现，

recently discovered the sword-tailed cricket has a novel survival strategy when it comes to life in their noisy environment.

剑尾蟋蟀在喧闹的环境中生活时，有一种新颖的生存策略。

"Up there, it's mainly other insects that produce noises that stop you from detecting what you really want to detect—and that is a predator⁴ that might attack you."

“在那里，主要是产生噪音的其他昆虫产生噪音会阻止你探听到你真正想要听到的东西——那是可能攻击你的捕食者。”

Every night, hundreds of species of hungry bats fly around the rain forest and use echolocation to hunt for their meals, which can include the cricket.

每天晚上，数百种饥饿的蝙蝠在雨林中飞来飞去，利用回声定位来觅食，它们的猎物可能包括蟋蟀。

"So we are talking neotropical rain forests, and they teem⁵ with different bat species. And most of them, or many of them, would be after insects.

“我们谈论的是新热带区雨林，那里到处都是各种种类的蝙蝠。其中大多数蝙蝠，或者说许多蝙蝠，都会追逐昆虫。

So the frequencies that they use to find the insect prey⁶ are covering pretty much a full echolocation-frequency range."

因此，它们用来发现昆虫猎物的频率几乎覆盖了回声定位的整个频率范围。”

Echolocation is great for hunting.

回声定位在狩猎中非常有用。

But Holderied says it's also a potential weakness for bats—because in the ultrasonic world, these calls are very, very loud.

但是霍尔德里德表示，这也是蝙蝠的潜在弱点，因为在超声世界，这些叫声非常非常响。

"And once you have cracked that, once you have evolved an ear that lets you hear these calls, you can simply fly away and escape into safety...."

“一旦你破解了它，一旦你进化出能让你听到这些叫声的耳朵，你就能飞离，逃到安全地带。”

Which the cricket has learned to do.

蟋蟀已经学会这样做了。

"Basically, they have a response threshold–that's what we call it. So they only respond to sounds that are very loud."

“基本上，它们拥有我们所说的反应阈值。因此它们只对非常响的声音有反应。”

And how do they respond? Well, they simply stop flying—and plummet⁷ toward the ground.

它们如何反应？它们只是停止飞行，然后突然降至地面。

"Sometimes they don't even drop all the way to the ground.

“有时它们甚至不会一直落到地面。

So if the calls are louder, they stop flying for a longer period of time–that means a longer drop.

如果声音比较响，它们会长时间停止飞行，这意味着长时间的停滞。

But if they stop for just a half a second, that might not be enough time for them to hit the ground.

但是如果它们只停下半秒种，那没有足够的时间让它们落到地面。

And after this half a second, they start flying again, but they're never actually crashing. But they drop out of the bat's approach vector."

半秒钟之后，它们会再次起飞，这不是真正的坠落，只是逃脱蝙蝠的追捕。”

The study of the crickets' novel survival strategy is in the journal Philosophical⁸ Transactions of the Royal Society B.

蟋蟀新奇生存策略的相关研究发表在《英国皇家学会哲学学报B》期刊上。

"It's a beautiful example of this predator-prey arms race."

“这是捕食者与猎物之间军备竞赛的漂亮例子。”

In this case, the passive prey has found a way to live, and listen for, another day.

在这个例子中，被动的猎物找到了一种生活方式，可以再活一天并再听一天。

Thanks for listening for Scientific American's 60-second Science. I'm Emily Schwing.

谢谢大家收听科学美国人——60秒科学。我是埃米莉·施温。

1 recording   

n.录音，记录

参考例句：

• How long will the recording of the song take?录下这首歌得花多少时间？
• I want to play you a recording of the rehearsal.我想给你放一下彩排的录像。

2 rustling   

n. 瑟瑟声，沙沙声 adj. 发沙沙声的

参考例句：

• the sound of the trees rustling in the breeze 树木在微风中发出的沙沙声
• the soft rustling of leaves 树叶柔和的沙沙声

3 ultrasonic   

adj.超声的；n.超声波

参考例句：

• It was very necessary for people to take type-B ultrasonic inspection regularly.定期进行B超检查是十分必要的。
• Sounds are classified into two kinds: sonic and ultrasonic.声波分为两类，即普通声波与超声波。

4 predator   

n.捕食其它动物的动物；捕食者

参考例句：

• The final part of this chapter was devoted to a brief summary of predator species.本章最后部分简要总结了食肉动物。
• Komodo dragon is the largest living lizard and a fearsome predator.科摩多龙是目前存在的最大蜥蜴，它是一种令人恐惧的捕食性动物。

5 teem   

vi.(with)充满，多产

参考例句：

• Good ideas teem in her head.她的头脑里好主意极多。
• Fish teem in the Chinese waters.中国近海鱼产丰富。

6 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。

7 plummet   

vi.(价格、水平等)骤然下跌；n.铅坠；重压物

参考例句：

• Mengniu and Yili have seen their shares plummet since the incident broke.自事件发生以来，蒙牛和伊利的股票大幅下跌。
• Even if rice prices were to plummet,other brakes on poverty alleviation remain.就算大米价格下跌，其它阻止导致贫困的因素仍然存在。

8 philosophical   

adj.哲学家的，哲学上的，达观的

参考例句：

• The teacher couldn't answer the philosophical problem.老师不能解答这个哲学问题。
• She is very philosophical about her bad luck.她对自己的不幸看得很开。