Multi-Modal Use of a Socially Directed Call in Bonobos

Abstract

‘Contest hoots’ are acoustically complex vocalisations produced by adult and subadult male bonobos (Pan paniscus). These calls are often directed at specific individuals and regularly combined with gestures and other body signals. The aim of our study was to describe the multi-modal use of this call type and to clarify its communicative and social function. To this end, we observed two large groups of bonobos, which generated a sample of 585 communicative interactions initiated by 10 different males. We found that contest hooting, with or without other associated signals, was produced to challenge and provoke a social reaction in the targeted individual, usually agonistic chase. Interestingly, ‘contest hoots’ were sometimes also used during friendly play. In both contexts, males were highly selective in whom they targeted by preferentially choosing individuals of equal or higher social rank, suggesting that the calls functioned to assert social status. Multi-modal sequences were not more successful in eliciting reactions than contest hoots given alone, but we found a significant difference in the choice of associated gestures between playful and agonistic contexts. During friendly play, contest hoots were significantly more often combined with soft than rough gestures compared to agonistic challenges, while the calls' acoustic structure remained the same. We conclude that contest hoots indicate the signaller's intention to interact socially with important group members, while the gestures provide additional cues concerning the nature of the desired interaction.

Social play as joint action: A framework to study the evolution of shared intentionality as an interactional achievement

“…Indeed, apes seem to possess some abilities necessary for understanding shared intentionality, like reading others' attention (Tomasello, Call, & Hare, 1998) and intentions (Call, Hare, Carpenter, & Tomasello, 2004;Call & Tomasello, 1998). They are also capable of communicating multi-modally to convey meaning (Genty, Clay, Hobaiter, & Zuberbühler, 2014;Hobaiter, Byrne, & Zuberbühler, 2017) and engaging in gestural turn-taking (Fröhlich et al, 2016a;Rossano, 2013). But they have difficulties participating in activities involving shared attention (Melis & Tomasello, 2013;Tomasello & Carpenter, 2005;Tomasello et al, 2005a).…”

The origin of meaning in animal signals

“…There is now an active area of research that examines the role of visual signals in primate social interactions (e.g. Genty, Clay, Hobaiter, & Zuberbühler, 2014), as well as a number of studies that examine the use of call combinations, particularly in forest monkeys (e.g. Arnold & Zuberbühler, 2012;Schlenker et al, in press).…”

Wild chimpanzees’ use of single and combined vocal and gestural signals

“…In great apes, this was largely done with captive groups (Leavens and Hopkins 2005; Pollick and de Waal 2007; Pollick et al 2008; Leavens et al 2010; Genty et al 2014). One common conclusion from this research has been that ‘multimodal’ signals in primates evolved not to enlarge the range of information that could be communicated, but simply to enhance detection (Pollick and de Waal 2007; Leavens et al 2010; Micheletta et al 2012; although c.f.…”