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科学60秒:动物开始“说话”只因夜太黑?

时间: 2020年03月10日 | 作者: Admin | 来源: 领研网(linkresearcher.com)



 [听力全文]


The animal kingdom is a noisy place. There’s bird song ... [CLIP: Bird whistle] ... choruses of frogs ... [CLIP: Frog chorus] ... and lots of lesser known sounds, like the ray gun–like sounds of baby alligators hatching and calling for Mom. [CLIP: Baby alligator sound]


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


“When I was a kid growing up, I had a pet alligator. It vocalized a lot.”


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


“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 make bellows and slaps and all sorts of sounds.”


Wiens and his collaborator Zhuo Chen wondered: Why did animals start vocalizing in the first place? 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.


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.


“So one of the things we did then was to do a statistical correlation between the evolution of acoustic 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.”


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


The findings are in the journal Nature Communications. [Zhuo Chen and John J. Wiens, The origins of acoustic communication in vertebrates]


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 dwellers 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. 


—Christopher Intagliata



 [重难点词汇、短语]


vocalize: v. 发声;说话

nocturnal: adj. 夜间的;夜间活动的

bellow: n. 吼叫声;v. 吼叫

vertebrate: n. 脊椎动物;adj. 有脊椎的;脊椎动物的

a shot in the dark: 瞎猜;盲干

gecko: n. 壁虎

pangolin: n.穿山甲



 [参考译文]


动物王国从来都是一个喧嚣之地,充斥着鸟儿的鸣叫、蛙群的合唱,还有很多鲜为人知的声音,比如短吻鳄宝宝孵化出壳、呼唤妈妈时,会发出像镭射枪一样的声音。

 

如果你很感兴趣的话,油管上有很多动物发声的视频。

 

亚利桑那大学(University of Arizona)的演化生态学家约翰·韦恩斯(John Wiens)说:“我小时候养过一条短吻鳄当宠物,它可没少叫唤。”

 

“我养这条鳄鱼宝宝的时候只有十几岁。有时候我会听到‘呃,呃,呃,呃’的声音。长大后,它们还会吼叫、发出拍打声以及其他各种各样的声音。”

 

韦恩斯和同事陈卓(Zhuo Chen,音译)想搞清楚:动物最先开始能够发声是因为什么?有一种假设理论认为,发声能力始于夜行动物,因为要知道当你还看不见时,声音要比颜色、角、或者其他视觉线索更有效。

 

韦恩斯和陈创建了一棵包含将近1 800种脊椎动物的演化树,在树上标记清楚每一种动物是日行动物还是夜行动物,以及它们是否会发声。

 

“所以,我们做的其中一件事情就是找出动物声音交流和活动时间(白天或者夜晚)之间的统计学关系。结果我们发现两者之间有着很强的相关性。那些夜间活跃的动物更倾向于演化出声音交流能力。”

 

这表明夜间活动不仅仅是在黑暗中一顿抓瞎。

 

研究结果发表在《自然·通讯》(Nature Communications)杂志上。

 

动物发声能力很可能是独立、多次演化的,早在千百万年之前就出现在蛙类、哺乳动物、壁虎、鸟类和鳄鱼身上。虽然发声能力可能起源于夜行动物,但有些“夜行者”似乎丧失了这一能力,比如穿山甲;而其他白天活跃的动物则保留了这一能力,当然,这就包括你和我。


翻译 阿金