Female Putty-Nosed Monkeys Use Experimentally Altered Contextual Information to Disambiguate the Cause of Male Alarm Calls

Kate Arnold,Klaus Zuberbühler,Nicolas Mathevon

doi:10.1371/journal.pone.0065660

Kate Arnold, Klaus Zuberbühler + Show 1 more

Open Access

https://doi.org/10.1371/journal.pone.0065660

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Journal: PLoS ONE	Publication Date: Jun 5, 2013
Citations: 77	License type: CC BY 4.0

Affiliation: University of St Andrews, University of Neuchâtel

Abstract

Many animal vocal signals are given in a wide range of contexts which can sometimes have little in common. Yet, to respond adaptively, listeners must find ways to identify the cause of a signal, or at least rule out alternatives. Here, we investigate the nature of this process in putty-nosed monkeys, a forest primate. In this species, adult males have a very restricted repertoire of vocalizations which are given in response to a wide variety of events occurring under conditions of limited visibility. We carried out a series of field playback experiments on females (N = 6) in a habituated group in Gashaka Gumti National Park, Nigeria, in which male alarm/loud calls were presented either alone, or following acoustic information that simulated the occurrence of natural disturbances. We demonstrate that listeners appear to integrate contextual information in order to distinguish among possible causes of calls. We conclude that, in many cases, pragmatic aspects of communication play a crucial role in call interpretation and place a premium on listeners' abilities to integrate information from different sources.

Highlights

Behavioral research on free-ranging primates, while challenging, is the most ecologically valid way to explore the evolutionary origins of human cognitive abilities, including precursors to language
The alarm calls of some bird and mammal species are regarded as being amongst the most informative because they are considered to be given to a relatively narrow range of external events. This high degree of production specificity has led to the description of such signals as ‘functionally referential’ [6]
The ‘eagle’ alarm calls of vervet and Diana monkeys are reported to be given only when a predatory eagle has been detected

Summary

Introduction

Behavioral research on free-ranging primates, while challenging, is the most ecologically valid way to explore the evolutionary origins of human cognitive abilities, including precursors to language. The alarm calls of some bird and mammal species are regarded as being amongst the most informative because they are considered to be given to a relatively narrow range of external events This high degree of production specificity has led to the description of such signals as ‘functionally referential’ [6]. Various studies have shown that predator-specific alarm calls, i.e., acoustically distinct alarm call types that ‘stand for’ different predator classes, are not universally present in primates (e.g., [15], [16]), and some, ground living, species, have graded, i.e., indistinct, alarm calls with low context specificity (e.g., [17], [18]) In these cases, the informative value of calls is low and it is generally accepted that listeners must bear the cognitive burden of extracting information from calls in order to generate meaning [19]. A proper assessment of production specificity, which entails systematic recording of all contexts in which the call occurs, is crucial in determining the potential information value of calls, this has rarely been attempted

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