# Functionally Deceptive Behaviours Tonkean Macaques (Macaca tonkeana): Intentional Tactical Deception or Behavioural Inhibition?

Isis Poitrasson, Charlotte Canteloup, James R Anderson, Nicolas Poulin, Hélène Meunier

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Isis Poitrasson, Charlotte Canteloup, James R Anderson, Nicolas Poulin, Hélène Meunier. Functionally Deceptive Behaviours Tonkean Macaques (Macaca tonkeana): Intentional Tactical Deception or Behavioural Inhibition?. European Federation of Primatology conference, Jul 2017, Strasbourg, France. pp.83. hal-04758169

HAL Id: hal-04758169

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Submitted on 29 Oct 2024

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# Functionally Deceptive Behaviours in Tonkean Macaques (Macaca tonkeana):
Intentional Tactical Deception or Behavioural Inhibition?

Isis Poitrasson<sup>a</sup>, Charlotte Canteloup<sup>abcd</sup>, James R. Anderson<sup>e</sup>, Nicolas Poulin<sup>f</sup>, Hélène Meunier<sup>abc</sup>

<sup>a</sup> Centre de Primatologie de l'Universite Primatologie de libition? 67207 Niederhausbergen, France

<sup>b</sup> Laboratoire de Neurosciences Cognitives et Adaptatives, UMR 7364, CNRS et Université de Strasbourg, France

<sup>c</sup> University of Strasbourg Institute for Advanced Study, 5 allée du Général Rouvillois, 67083 Strasbourg, France

<sup>d</sup> University of Zürich, Anthropological Institute & Museum, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland

<sup>e</sup> Department of Psychology, Kyoto University Graduate. School of Letters, Yoshida15 honmachi, Sakyo, Kyoto 606-8501, Japan

<sup>f</sup> Centre Statistique de Strasbourg, IRMA, UMR 7501, 7, rue René Descartes, 67084 Strasbourg Cedex, France

E-Mail: isispoitrasson@hotmail.com

The complex social networks and competitive interactions of primates create abundant opportunities for engaging in deceptive behaviours. To examine such behaviours, we tested subordinate Tonkean macaques with dominant conspecifics in an experimental food competition context. The subordinate macaque could see two pieces of food whereas the dominant could only see one. The two individuals were released into the testing area at the same time or with the subordinate given a short head start on the dominant. Using detailed video analysis of the behaviours of both individuals, our goals were to: i) describe and classify functionally deceptive strategies displayed by subordinates; ii) determine factors influencing the use of these strategies, and iii) investigate whether subordinates adjusted their behaviour in response to the behaviour of the dominant. Our study revealed that subordinates could use different types of tactical deception, including concealment and distraction, and even combine more than one strategy. They resorted to deceptive behaviours especially when paired with competitors of much higher social rank but also against certain individuals, regardless of the hierarchical gap, leading us to believe some individual characteristics may also be taken into account. Finally, the video analysis revealed significant interactions between subordinate and dominant's behaviours, suggesting that subordinates tailored their behaviour to those of dominants. While this latter result does not allow us to conclude on the use of tactical deception by Tonkean macaques as an intentional strategy, it reveals that they are at least highly skillful behaviour-readers. This research meets with the European Directive 2010/63/EU and was approved by the Animal Experiment Committee of the Centre de Primatologie de l'Université de Strasbourg and by the CREMEAS Ethics Committee (Approval for conducting experiments on primates: AL/46/53/02/13).