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The Acoustic Structure and Information Content of Female Koala Vocal Signals

Determining the information content of animal vocalisations can give valuable insights into the potential functions of vocal signals. The source-filter theory of vocal production allows researchers to examine the information content of mammal vocalisations by linking variation in acoustic features w...

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Autor principal: Charlton, Benjamin D.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4605621/
https://www.ncbi.nlm.nih.gov/pubmed/26465340
http://dx.doi.org/10.1371/journal.pone.0138670
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author Charlton, Benjamin D.
author_facet Charlton, Benjamin D.
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description Determining the information content of animal vocalisations can give valuable insights into the potential functions of vocal signals. The source-filter theory of vocal production allows researchers to examine the information content of mammal vocalisations by linking variation in acoustic features with variation in relevant physical characteristics of the caller. Here I used a source-filter theory approach to classify female koala vocalisations into different call-types, and determine which acoustic features have the potential to convey important information about the caller to other conspecifics. A two-step cluster analysis classified female calls into bellows, snarls and tonal rejection calls. Additional results revealed that female koala vocalisations differed in their potential to provide information about a given caller’s phenotype that may be of importance to receivers. Female snarls did not contain reliable acoustic cues to the caller’s identity and age. In contrast, female bellows and tonal rejection calls were individually distinctive, and the tonal rejection calls of older female koalas had consistently lower mean, minimum and maximum fundamental frequency. In addition, female bellows were significantly shorter in duration and had higher fundamental frequency, formant frequencies, and formant frequency spacing than male bellows. These results indicate that female koala vocalisations have the potential to signal the caller’s identity, age and sex. I go on to discuss the anatomical basis for these findings, and consider the possible functional relevance of signalling this type of information in the koala’s natural habitat.
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spelling pubmed-46056212015-10-29 The Acoustic Structure and Information Content of Female Koala Vocal Signals Charlton, Benjamin D. PLoS One Research Article Determining the information content of animal vocalisations can give valuable insights into the potential functions of vocal signals. The source-filter theory of vocal production allows researchers to examine the information content of mammal vocalisations by linking variation in acoustic features with variation in relevant physical characteristics of the caller. Here I used a source-filter theory approach to classify female koala vocalisations into different call-types, and determine which acoustic features have the potential to convey important information about the caller to other conspecifics. A two-step cluster analysis classified female calls into bellows, snarls and tonal rejection calls. Additional results revealed that female koala vocalisations differed in their potential to provide information about a given caller’s phenotype that may be of importance to receivers. Female snarls did not contain reliable acoustic cues to the caller’s identity and age. In contrast, female bellows and tonal rejection calls were individually distinctive, and the tonal rejection calls of older female koalas had consistently lower mean, minimum and maximum fundamental frequency. In addition, female bellows were significantly shorter in duration and had higher fundamental frequency, formant frequencies, and formant frequency spacing than male bellows. These results indicate that female koala vocalisations have the potential to signal the caller’s identity, age and sex. I go on to discuss the anatomical basis for these findings, and consider the possible functional relevance of signalling this type of information in the koala’s natural habitat. Public Library of Science 2015-10-14 /pmc/articles/PMC4605621/ /pubmed/26465340 http://dx.doi.org/10.1371/journal.pone.0138670 Text en © 2015 Benjamin D. Charlton http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Charlton, Benjamin D.
The Acoustic Structure and Information Content of Female Koala Vocal Signals
title The Acoustic Structure and Information Content of Female Koala Vocal Signals
title_full The Acoustic Structure and Information Content of Female Koala Vocal Signals
title_fullStr The Acoustic Structure and Information Content of Female Koala Vocal Signals
title_full_unstemmed The Acoustic Structure and Information Content of Female Koala Vocal Signals
title_short The Acoustic Structure and Information Content of Female Koala Vocal Signals
title_sort acoustic structure and information content of female koala vocal signals
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4605621/
https://www.ncbi.nlm.nih.gov/pubmed/26465340
http://dx.doi.org/10.1371/journal.pone.0138670
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