2020托福听力练习：老鼠用唱歌吸引异性（下载）

　　How do you attract a mate?

　　If you're a male mouse, you take the Frank Sinatra approach—you sing.

　　Scientists have known about crooning male mice for years.

　　And past experiments showed that if you leave male mice alone with an unconscious female or even with just a trace of her urine, the males will sing.

　　If you reverse roles, the females do not sing.

　　So scientists believed that in courtship, males made all the noise.

　　Until now.

　　“The problem with the field is that we've never had a way to figure out who's vocalizing.”

　　Neuroscientist Josh Neunuebel at University of Delaware.

　　He realized that researchers needed better listening tools.

　　So Neunuebel built a mouse sized recording studio.

　　His team lined a small closet with nylon mesh and foam, which absorb sound rather than reflect it.

　　And they installed ultrasonic microphones, because mice make sounds at a frequency that's above the range of human hearing.

　　That's some mouse singing slowed down so we can hear it.

　　Neunuebel's set-up made it possible for the researchers to determine that some songs were in fact coming from female mice.

　　The gals that sang back to the males pursuing them also slowed down their pace, as if to say:

　　“Hey! I'm interested in you. Catch me if you can.”

　　The study is in the journal eLife.

　　Neunuebel still wants to work out more details about how these interactions occur.

　　But with improved technology, maybe the researchers can pick out pick-up lines.

　　At least the ones that sound nice…to mice.