Nonlinearities in Meerkat Alarm Calls Prevent Receivers from Habituating

Authors

  • Denise Karp,

    1. Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
    2. Kalahari Meerkat Project, Kuruman River Reserve, Vanzylrus, Northern Cape, South Africa
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  • Marta B. Manser,

    1. Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
    2. Kalahari Meerkat Project, Kuruman River Reserve, Vanzylrus, Northern Cape, South Africa
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  • Elizabeth M. Wiley,

    1. Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
    2. Kalahari Meerkat Project, Kuruman River Reserve, Vanzylrus, Northern Cape, South Africa
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  • Simon W. Townsend

    Corresponding author
    1. Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
    2. Kalahari Meerkat Project, Kuruman River Reserve, Vanzylrus, Northern Cape, South Africa
    • Correspondence

      Simon W. Townsend, Institute of Evolutionary Biology and Environmental Studies, Winterthurerstrasse 190, University of Zurich, 8057 Zurich, Switzerland.

      E-mail: simon.townsend@ieu.uzh.ch

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Abstract

Despite the fact that nonlinearities are present in the calls of a number of different species, their adaptive function has received little empirical investigation. Previous studies have demonstrated that playbacks of nonlinear calls evoke a more extreme behavioural response and lead to an increase in responsiveness compared with control playbacks without nonlinearities. Consequently, it has been suggested that nonlinearities might prevent receivers from habituating, by increasing the unpredictability of the call (‘unpredictability hypothesis’). In this study, we tested the unpredictability hypothesis, specifically whether nonlinearities prevent receivers from habituating, by means of a playback experiment using meerkat (Suricata suricatta) alarm calls. We found that in meerkats, playbacks of naturally occurring nonlinear alarm calls take longer to habituate to than alarm calls without any nonlinear intrusions. These data provide important empirical support for the hypothesis that nonlinearities are not just an irrelevant by-product of the vocal production system, but indeed function adaptively.

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