科学美国人60秒 SSS 听不见我的声音?!

This Frog Can't Hear Its Own Calls

In the frog world, romance is often accompanied by a song. "It's the norm. The vast majority of frogs have males calling to attract females."

在青蛙的世界，浪漫总与歌声相随。“这是一种常态。绝大多数的雄性青蛙通过叫声来吸引雌性青蛙。”

Sandra Goutte is an evolutionary biologist and herpetologist at the University of Campinas, in Brazil. And she studies frogs called 'pumpkin toadlets' from the cloud forests of coastal Brazil. "They're extremely cool, they're teeny tiny." They're neon orange, and they wave their arms around when they feel threatened, "by either predator or herpetologist."

Goutte是巴西卡达纳斯大学的进化生物学家和爬虫学者。她研究了巴西沿海温带雨林里一种名为“南瓜角蛙”的青蛙。“这种青蛙及其孤傲，并且非常的小。呈霓虹色，当受到来自捕食者或者爬虫学者的威胁时，它们就会四处挥舞胳膊。”

And, true to frog form, "they make this slow call that sounds like a cricket, like "che che."

而对于青蛙来说，“它们发出的这种缓慢的声音听起来就像蟋蟀的叫声。”

But here's the weird part: it appears the pumpkin toadlets are not able to hear the sounds they make. Goutte and her colleagues playing recordings of the calls to the frogs to look for reactions. The researchers also traced electrical impulses from the frogs' ears to their brains, and even dissected the frog inner ear.

但是奇怪的是：南瓜蛙似乎听不到自己发出的声音。 Goutte 和她的同事们播放了它们的叫声以探寻南瓜蛙的反应。研究人员还追踪研究了从南瓜蛙耳朵到大脑的电脉冲信号，甚至还分析了青蛙的内耳。

And it turns out, the frogs just don't have the equipment to hear their own voices. The study is in the journal Scientific Reports.

结果表明，南瓜蛙并不具有能识别自己声音的器官。该研究结果发表在《科学报告》杂志上。

"Why would they call if they cannot hear their own calls, right?" Goutte does have a few theories. Perhaps, she says, the bulging throat movement associated with calling is a sexual signal, with the sound an inadvertent accompaniment—perhaps the frogs lost the ability to hear the calls at some point in their evolutionary history, when the displays did the job well enough on their own. After all, they're a highly visual species—out during the day, brightly colored, do the hand-waving thing.

“如果听不见自己的叫声，那为什么南瓜蛙还要叫呢?”Goutte 阐述了自己的一些观点。她说道，喉咙的鼓胀伴随发出的声音其实是一种性信号，同时伴着无意的节奏——或许南瓜蛙在进化的过程中失去了听到自己叫声的能力，因为那样的“演奏”已经能独当一面了。毕竟，它们很招摇啊——长相光鲜亮丽，白天大胆外出，甚至还挥手示意。

Pumpkin toadlets are the only species unable to hear themselves. At least, as far as we know. "The thing is, it was really hard to convince even some of the co-authors to do the experiments, because they were like, 'Why would you test their hearing?

南瓜蛙是唯一不能听到自己声音的物种。至少，在我们目前看来是这样的。“因为现在的问题在于，很难说服一些合作人员去做实验，因为这些人会问“为什么要测试它们的听力呢?”

If they're calling, they hear, they must hear, right?' So I think it's also the way we're doing science—we're not testing these obvious things. So maybe there are more examples out there but we don't know any yet." One can only hope that future research proposals will get a fair hearing.

如果自己发出叫声，它们应该听到的，必须能听到，对吧?所以，这就是我们做实验的方式——我们并不去测试那些显而易见的事物。“也许还会有其他一些类似的物种，但是我们现在尚无可知。”只希望未来的研究内容会还南瓜蛙一个公道。