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This is Scientific American's 60-second Science, I'm Christopher Intagliata.

这里是科学美国人——60秒科学系列，我是克里斯托弗·因塔格里塔。

The animal kingdom is a noisy place. There's bird song...

动物王国是个喧闹的地方。这里有鸟鸣……

(CLIP: Bird whistle)

（音频剪辑：鸟鸣）

...choruses of frogs...

蛙声……

(CLIP: Frog chorus)

（音频剪辑：蛙声）

...and lots of lesser¹ known sounds, like the ray gun–like sounds of baby alligators³ hatching and calling for Mom.

……还有许多鲜为人知的声音，比如小短吻鳄被孵化和呼唤妈妈时发出的射线枪般的声音。

(CLIP: Baby alligator² sound)

（音频剪辑：短吻鳄宝宝的声音）

There's lots of videos of them doing this on YouTube if you're curious.

如果你感到好奇，YouTube网站上有许多这类视频。

"When I was a kid g?rowing up, I had a pet alligator. It vocalized a lot."

“我小时候养过短吻鳄当宠物，它总是叫。”

John Wiens, an evolutionary⁴ ecologist at the University of Arizona.

亚利桑那大学的进化生态学家约翰·维恩斯说到。

"So I had this baby alligator when I was a teenager. Sometimes I could hear 'Urh urh urh urh.' And when they grow up, they do bellows⁵ and slaps and all sorts of sounds."

“我是在十几岁的时候养的那只小短吻鳄。有时我能听到‘呃呃呃’的声音。它们在成长过程中会发出吼叫和‘啪啪'等各种声音。”

Wiens and his collaborator⁶ Zhuo Chen wondered: Why did animals start vocalizing in the first place? Well, one hypothesis was that the ability originated in nocturnal animals—cause, you know, sound works a lot better than colors or horns or other visual cues when you can't see.

维恩斯及其合作者卓晨想知道：动物最初发出叫声的原因是什么？一种假设认为，这种能力源于夜间行动物，因为在看不见的情况下，声音比颜色、角或其他视觉提示的效果要好得多。

Wiens and Chen built an evolutionary tree of nearly 1,800 vertebrate species and mapped onto it information on whether each lived by day or night and whether they made sound.

维恩斯和Chen为近1800种脊椎动物建立了进化树，并标注了每种动物是日行还是夜行，以及是否发声的信息。

"So one of the things we did then was to do a statistical⁷ correlation⁸ between the evolution of acoustic⁹ communication and whether they were active by day or by night. And we found a very strong relationship. Those that are active at night tend to evolve acoustic communication."

“因此，我们之后所做的，就是在声通讯进化与它们是日间活跃还是夜间活跃这二者之间做统计相关性。我们发现二者间存在非常紧密的关系。在夜间活动的动物往往会进化出声通讯。”

Suggesting that the nocturnal notion was more than just a shot in the dark.

这表明夜行概念不仅仅是在黑暗中活动。

The findings are in the journal Nature Communications.

这项研究发表在《自然·通讯》期刊上。

This ability to vocalize likely arose independently, multiple times, hundreds of millions of years ago—in frogs, mammals, geckos, and birds and crocodilians. And though vocalization might have originated with nocturnal animals, some night dwellers¹⁰ seem to have lost the ability—like pangolins—while others, which evolved to be active by day, retained it—like, of course, you and me.

这种发声能力很可能在数亿年前独立且多次在青蛙、哺乳动物、壁虎、鸟类和鳄鱼身上产生。虽然最早发声的可能是夜行动物，但穿山甲等夜行动物似乎已经失去了这一能力，而其它进化为日间活跃的动物，依旧保留着发声能力，当然，就像你我一样。

Thanks for listening for Scientific American's 60-second Science. I'm Christopher Intagliata.

谢谢大家收听科学美国人——60秒科学。我是克里斯托弗·因塔利亚塔。