Pika’s research (2008) revealed that monkeys are able to notify fellow members in the family. This was determined when one monkey had eye-to-eye close contact with another monkey before moving onto another task. It is possible that the first monkey was emphasizing a point to the other monkey. The research also revealed that monkeys were able to attract a fellow monkey’s attention by conducting the action of slapping the ground. Different species of monkeys have also been found to use different varieties of manual gestures and postures, varying as a function of social rank and contexts (Maestripieri, 1999).
Pika (2008) also showed that apes produced communicative gestures that were specific to its species. Ogden & Schildkraut (1991) suggested that gorillas are able to produce a combination of auditory and visual gestures. Some specific gestures include the splash display (Parnell & Buchanan-Smith, 2001) and the hand clapping (Fay, 1989). Arbib et al. (2008) revealed that gorillas in captive are able to utilize a variety of at least 30 different tactile, visual and auditory gestures.
A recent study conducted by the University of St Andrews also records up to 66 different gestures that show how chimpanzees communicate, such as the tapping of another chimpanzee to indicate ‘stop that’ and the raising of an arm to indicate ‘give me that’ (Brooks-Pollock, 2014). Even with such a “gestural lexicon” on chimpanzees created, many variances were observed in the communication of a certain meaning, suggesting that different groups of monkeys develop their respective sets of gestural repertoires. Nonetheless, Hobaiter & Bryne (2014) explained that just with human words, some gestures by the chimpanzees have several senses, but the meanings remain the same irrespective of who uses them.
This information on the gestural system in non-human primates suggests the primitive origins of gestures as a form of communication even with the absence of speech, providing additional insight to the gestural-first theory in the study of evolutionary linguistics, particularly in the recent years.
Here’s a video that shows how the “chest beat” (as performed innocently by the little girl) has agitated a gorilla, due to the gesture signifying an act of dominance and aggression: