Orangutan gives clues to the origins of human speech

An orangutan called Rocky could provide the key to understanding how speech in humans evolved from the time of the ancestral great apes, according to a study led by Dr Adriano Lameira of Durham University and published in the journal Scientific Reports . Learned behaviour Dr Lameira , a Junior Research Fellow in the Department of Anthropology led a research project to look at whether an orangutan could demonstrate the ability to learn new sounds and control its voice. Previously it was thought that great apes, our closest evolutionary relatives, could not learn to produce new sounds. As the human ability to speak is a learned behaviour it was therefore thought that this could not have originated from the great apes. It was also believed that control over the voice, or vocal fold action, which would give them the capacity to learn vowel-like sounds, was not an ability the great apes had. New sounds However, the research team found that Rocky, an orangutan living at Indianapolis Zoo in the USA, was able to copy the pitch and tone of sounds made by researchers to make vowel-like calls. The research team compared these sounds against the largest available database of orangutan calls collected from over 12,000 hours of observations of more than 120 orangutans from 15 wild and captive populations.