People may think they invented the “deaf” language from which hands hurt after a lively conversation. But the real discoverers of sign language speech are the orangutans of South Asia.
Two British scientists have announced that these great apes communicate with purposeful gestures that have a certain meaning.
Erica Cartmill and Richard Byrne noted the orangutans’ gestures, comparing the whistleblower’s alleged intent to the eventual satisfaction of the goal achieved. So they collected a dictionary of words or phrases expressed by gestures.
The researchers observed 28 orangutans at three European zoos for nine months. 64 types of gestures were identified, 40 of which were used frequently enough to achieve any of the following goals: to intercept interaction (contact, postage or play), to request objects, to share them, to start a joint movement, to force a partner to step down or to terminate any action.
The scientists also tracked what would happen if the “recipient” of the message did not respond to the gesture. It turned out that the reporter became more insistent in the expressions.