Scientists from Durham University from the UK have followed an ape from the Indianapolis Zoo as they were trying to figure out how human speech evolved over time.
The research revealed the fact that the orangutans can control their voices to produce the same sounds as humans do. The orangutan Rocky, at eight years of age, was able to mimic the tone and the pitch made by the researchers.
In a previous study, the same author discovered that a female orangutan from Amsterdam was able to produce sounds that had the same pace and rhythm as human speech.
The experiments involved in this more recent study went on in 2012 when the researchers played a mime game with the orangutan. The biologists would make a random sound, and the ape would try to make the same sound.
Then, the researchers compared the sounds made by Rocky with the recordings of over 120 orangutans that were both in the wild and in captivity.
The conclusion was that none of the sounds produced by the ape while mimicking the researcher could be found in the recordings of the other orangutans. Therefore, Rocky was able to learn new sounds and to control his voice.
Voice control is thought to be critical to the evolution of spoken language as it implies the formation of the vocal systems. Until now, scientists believed that the great apes were not capable of vocal learning and to expand the vocal repertoire. However, the orangutans proved the capacity to control the oscillation of vocal fold.
As the great apes are also capable of being very sociable, they can also socially learn how to produce voiceless calls that resemble consonants and novel vowel calls, as pre-requisites of spoken language ability.
The study focused on a hot topic in the scientific world, as the researchers have long tried to figure out whether or not the early human ancestors could produce new noises.
Until now, the theory was that the sounds were produced by apes that were driven by arousal and that they had no control over the sounds they were emitting. The new study proves the theory wrong, and therefore it may be possible that the early hominids had vocal capacities.
The early hominids are the creatures living before the humans and the apes split in the evolution of the species.
The scientists want to investigate further how the vocal system evolved and got transformed in speech.
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