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Subglottal pressure and fundamental frequency control in contact calls of juvenile Alligator mississippiensis

Vocalization is rare among non-avian reptiles, with the exception of the crocodilians, the sister taxon of birds. Crocodilians have a complex vocal repertoire. Their vocal and respiratory system is not well understood but appears to consist of a combination of features that are also found in the ext...

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Autores principales: Riede, Tobias, Tokuda, Isao T., Farmer, C. G.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Company of Biologists 2011
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3160820/
https://www.ncbi.nlm.nih.gov/pubmed/21865521
http://dx.doi.org/10.1242/jeb.051110
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author Riede, Tobias
Tokuda, Isao T.
Farmer, C. G.
author_facet Riede, Tobias
Tokuda, Isao T.
Farmer, C. G.
author_sort Riede, Tobias
collection PubMed
description Vocalization is rare among non-avian reptiles, with the exception of the crocodilians, the sister taxon of birds. Crocodilians have a complex vocal repertoire. Their vocal and respiratory system is not well understood but appears to consist of a combination of features that are also found in the extremely vocal avian and mammalian taxa. Anatomical studies suggest that the alligator larynx is able to abduct and adduct the vocal folds, but not to elongate or shorten them, and is therefore lacking a key regulator of frequency, yet alligators can modulate fundamental frequency remarkably well. We investigated the morphological and physiological features of sound production in alligators. Vocal fold length scales isometrically across a wide range of alligator body sizes. The relationship between fundamental frequency and subglottal pressure is significant in some individuals at some isolated points, such as call onset and position of maximum fundamental frequency. The relationship is not consistent over large segments of the call. Fundamental frequency can change faster than expected by pressure changes alone, suggesting an active motor pattern controls frequency and is intrinsic to the larynx. We utilized a two-mass vocal fold model to test whether abduction and adduction could generate this motor pattern. The fine-tuned interplay between subglottal pressure and glottal adduction can achieve frequency modulations much larger than those resulting from subglottal pressure variations alone and of similar magnitude, as observed in alligator calls. We conclude that the alligator larynx represents a sound source with only two control parameters (subglottal pressure and vocal fold adduction) in contrast to the mammalian larynx in which three parameters can be altered to modulate frequency (subglottal pressure, vocal fold adduction and length/tension).
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spelling pubmed-31608202011-09-15 Subglottal pressure and fundamental frequency control in contact calls of juvenile Alligator mississippiensis Riede, Tobias Tokuda, Isao T. Farmer, C. G. J Exp Biol Research Articles Vocalization is rare among non-avian reptiles, with the exception of the crocodilians, the sister taxon of birds. Crocodilians have a complex vocal repertoire. Their vocal and respiratory system is not well understood but appears to consist of a combination of features that are also found in the extremely vocal avian and mammalian taxa. Anatomical studies suggest that the alligator larynx is able to abduct and adduct the vocal folds, but not to elongate or shorten them, and is therefore lacking a key regulator of frequency, yet alligators can modulate fundamental frequency remarkably well. We investigated the morphological and physiological features of sound production in alligators. Vocal fold length scales isometrically across a wide range of alligator body sizes. The relationship between fundamental frequency and subglottal pressure is significant in some individuals at some isolated points, such as call onset and position of maximum fundamental frequency. The relationship is not consistent over large segments of the call. Fundamental frequency can change faster than expected by pressure changes alone, suggesting an active motor pattern controls frequency and is intrinsic to the larynx. We utilized a two-mass vocal fold model to test whether abduction and adduction could generate this motor pattern. The fine-tuned interplay between subglottal pressure and glottal adduction can achieve frequency modulations much larger than those resulting from subglottal pressure variations alone and of similar magnitude, as observed in alligator calls. We conclude that the alligator larynx represents a sound source with only two control parameters (subglottal pressure and vocal fold adduction) in contrast to the mammalian larynx in which three parameters can be altered to modulate frequency (subglottal pressure, vocal fold adduction and length/tension). Company of Biologists 2011-09-15 /pmc/articles/PMC3160820/ /pubmed/21865521 http://dx.doi.org/10.1242/jeb.051110 Text en © 2011. http://creativecommons.org/licenses/by-nc-sa/3.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial Share Alike License, which permits unrestricted non-commercial use, distribution and reproduction in any medium provided that the original work is properly cited and all further distributions of the work or adaptation are subject to the same Creative Commons License terms.
spellingShingle Research Articles
Riede, Tobias
Tokuda, Isao T.
Farmer, C. G.
Subglottal pressure and fundamental frequency control in contact calls of juvenile Alligator mississippiensis
title Subglottal pressure and fundamental frequency control in contact calls of juvenile Alligator mississippiensis
title_full Subglottal pressure and fundamental frequency control in contact calls of juvenile Alligator mississippiensis
title_fullStr Subglottal pressure and fundamental frequency control in contact calls of juvenile Alligator mississippiensis
title_full_unstemmed Subglottal pressure and fundamental frequency control in contact calls of juvenile Alligator mississippiensis
title_short Subglottal pressure and fundamental frequency control in contact calls of juvenile Alligator mississippiensis
title_sort subglottal pressure and fundamental frequency control in contact calls of juvenile alligator mississippiensis
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3160820/
https://www.ncbi.nlm.nih.gov/pubmed/21865521
http://dx.doi.org/10.1242/jeb.051110
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