Newfound organ gives male koalas their low-Ditched voice

摘要

Koalas have a newly discovered extra set of vocal cords that allows males to hit notes 20 times lower than expected. The sizes of an animal's voice box and its flapping vocal cords dictate the range of pitches an animal can make, so a typical 8-kilogram koala should sit near the soprano section. But the male's mating call, which to humans sounds like a string of belches and snorts, dips to tones usually made only by elephant-sized mammals. Benjamin Charlton of England's University of Sussex and colleagues dissected the voice boxes of 10 male koalas.