AsianScientist (Aug. 23, 2012) – Researchers in Japan have discovered that singing gibbons use the same vocal techniques that take professional soprano singers years to master, revealing a physiological similarity between primate singing and human voices.
A gibbon’s song is acoustically unique among primates, with a loud melody which can be heard over three kilometers away. In the wild, gibbons use their songs to communicate with neighboring pairs, strangers and potential mates through impenetrable jungle where visibility is poor.
The study, published in the American Journal of Physical Anthropology, studied the singing of a white-handed gibbon (Hylobates lar) at Fukuchiyama City Zoo, in northern Kyoto.
“The complexity of human speech is unique among primates as it requires varied soft sounds made by the rapid movements of vocal tracts,” said Dr. Takeshi Nishimura, the leader of the research team at Kyoto University.
“Our speech was thought to have evolved through specific modifications in our vocal anatomy. However, we’ve shown how the gibbons’ distinctive song uses the same vocal mechanics as soprano singers, revealing a fundamental similarity with humans.”
To explore these similarities the team conducted an acoustic investigation using helium gas, which is for making human voices appear high pitched. The gas is useful for studying animal vocal mechanisms as it increases sound velocity and resonance frequencies in the vocal tract.
The team recorded 20 gibbon calls in normal air atmosphere, before recording 37 calls in a helium-enriched atmosphere. The resulting sounds reveal how gibbons can consciously manipulate their vocal cords and tract to make their distinctive sound.
“This is the first evidence that gibbons always sing using soprano techniques, a difficult vocalisation ability for humans which is only mastered by professional opera singers,” concluded Nishimura.
The discovery also suggests that the development of complex vocal abilities in humans was not due to unique evolutionary modifications. Instead, it shows that humans share the biological fundamentals of vocalisation with other primates, but in speech have simply acquired another of its most sophisticated forms.
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Source: American Journal of Physical Anthropology (Wiley); Photo: Getty Images.
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