While they may not be as talkative as King Louie from Disney’s The Jungle Book, it turns out wild orangutans have some serious communication skills. Researchers at the University of Exeter have identified 11 vocal signals and 21 physical “gesture types” that the Great Apes use to communicate with one another.
The findings reveal orangutans are highly responsive to communication, reacting either before gesturing ended or in less than a second in 90 per cent of communications.
The team studied video footage of 16 orangutans consisting of seven mother-child pairs and a pair of siblings, noting a total of 1,299 communicative signals – 858 vocal signals and 441 gestures.
The sounds included the “kiss squeak” – a sharp kiss noise created while inhaling, the “grumph” – a low sound lasting one or two seconds made on the inhale, the “gorkum” – a kiss squeak followed by a series of multiple grumphs, and the self-explanatory “raspberry”.
Gestures included beckoning, stamping, pushing out a lower lip, shaking objects and “presenting” a body part.
They identified eight goals or requests of the communications: “acquire object”, “climb on me”, “climb on you”, “climb over”, “move away”, “decrease intensity”, “resume play” and “stop that”.
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“Orangutans are the most solitary of all the apes, which is why most studies have been done on African apes, and not much is known about wild orangutan gestures,” said University of Exeter scientist Dr Helen Morrogh-Bernard. “We spent two years filming more than 600 hours of footage of orangutans in the Sabangau peat swamp forest in Borneo, Indonesia. While some of our findings support what has been discovered by zoo-based studies, other aspects are new – and these highlight the importance of studying communication in its natural context.”
More signals are likely to be identified in the future, the researchers say.