Not here, there! Possible referential gesturing during allogrooming by wild bonnet macaques, Macaca radiata

Area of Science:

• Primate communication
• Animal behavior
• Evolution of language

Background:

• Intentional referential gestures are key to human language and observed in some primates.
• Apes use spontaneous gestures; only captive macaques show learned gestures.
• Referential gestures were previously only documented in chimpanzees.

Purpose of the Study:

• To investigate potentially referential and intentional gesturing in wild bonnet macaques (Macaca radiata).
• To expand the understanding of gestural communication in non-ape primates.
• To contribute to the evidence for early human language-like capacities in non-human species.

Main Methods:

• Observational study of wild bonnet macaques during allogrooming interactions.
• Documentation of distinct gestures used to indicate body parts for grooming.
• Analysis of gesture effectiveness in directing recipient's attention.

Main Results:

• Bonnet macaques were observed using four distinct intentional gestures during allogrooming.
• These gestures successfully directed the grooming partner's attention to specific body areas.
• Recipients subsequently groomed the indicated body part.

Conclusions:

• This study provides the first evidence of potentially referential and intentional gesturing in wild bonnet macaques.
• The findings broaden the scope of gestural communication in non-ape primates.
• This research supports the hypothesis of early language-like capacities in non-human species.