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Formants provide honest acoustic cues to body size in American alligators

Reber, Stephan Alexander LU ; Janisch, Judith ; Torregrosa, Kevin ; Darlington, Jim ; Vliet, Kent A. and Fitch, W. Tecumseh (2017) In Scientific Reports 7(1).
Abstract
In many vertebrates, acoustic cues to body size are encoded in resonance frequencies of the vocal tract (“formants”), rather than in the rate of tissue vibration in the sound source (“pitch”). Anatomical constraints on the vocal tract’s size render formants honest cues to size in many bird and mammal species, but it is not clear whether this correlation evolved convergently in these two clades, or whether it is widespread among amniotes (mammals, birds, and non-avian reptiles). We investigated the potential for honest acoustic cues in the bellows of adult American alligators and found that formant spacing provided highly reliable cues to body size, while presumed correlates of the source signal did not. These findings held true for both... (More)
In many vertebrates, acoustic cues to body size are encoded in resonance frequencies of the vocal tract (“formants”), rather than in the rate of tissue vibration in the sound source (“pitch”). Anatomical constraints on the vocal tract’s size render formants honest cues to size in many bird and mammal species, but it is not clear whether this correlation evolved convergently in these two clades, or whether it is widespread among amniotes (mammals, birds, and non-avian reptiles). We investigated the potential for honest acoustic cues in the bellows of adult American alligators and found that formant spacing provided highly reliable cues to body size, while presumed correlates of the source signal did not. These findings held true for both sexes and for all bellows whether produced in or out of water. Because birds and crocodilians are the last extant Archosaurians and share common ancestry with all extinct dinosaurs, our findings support the hypothesis that dinosaurs used formants as cues to body size. The description of formants as honest signals in a non-avian reptile combined with previous evidence from birds and mammals strongly suggests that the principle of honest signalling via vocal tract resonances may be a broadly shared trait among amniotes. (Less)
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author
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publishing date
type
Contribution to journal
publication status
published
subject
in
Scientific Reports
volume
7
issue
1
article number
1816
publisher
Nature Publishing Group
external identifiers
  • scopus:85019257819
ISSN
2045-2322
DOI
10.1038/s41598-017-01948-1
language
English
LU publication?
no
id
10209a99-a316-46d1-a89f-8b72cd922a40
date added to LUP
2018-10-03 00:05:17
date last changed
2022-04-25 17:32:34
@article{10209a99-a316-46d1-a89f-8b72cd922a40,
  abstract     = {{In many vertebrates, acoustic cues to body size are encoded in resonance frequencies of the vocal tract (“formants”), rather than in the rate of tissue vibration in the sound source (“pitch”). Anatomical constraints on the vocal tract’s size render formants honest cues to size in many bird and mammal species, but it is not clear whether this correlation evolved convergently in these two clades, or whether it is widespread among amniotes (mammals, birds, and non-avian reptiles). We investigated the potential for honest acoustic cues in the bellows of adult American alligators and found that formant spacing provided highly reliable cues to body size, while presumed correlates of the source signal did not. These findings held true for both sexes and for all bellows whether produced in or out of water. Because birds and crocodilians are the last extant Archosaurians and share common ancestry with all extinct dinosaurs, our findings support the hypothesis that dinosaurs used formants as cues to body size. The description of formants as honest signals in a non-avian reptile combined with previous evidence from birds and mammals strongly suggests that the principle of honest signalling via vocal tract resonances may be a broadly shared trait among amniotes.}},
  author       = {{Reber, Stephan Alexander and Janisch, Judith and Torregrosa, Kevin and Darlington, Jim and Vliet, Kent A. and Fitch, W. Tecumseh}},
  issn         = {{2045-2322}},
  language     = {{eng}},
  number       = {{1}},
  publisher    = {{Nature Publishing Group}},
  series       = {{Scientific Reports}},
  title        = {{Formants provide honest acoustic cues to body size in American alligators}},
  url          = {{http://dx.doi.org/10.1038/s41598-017-01948-1}},
  doi          = {{10.1038/s41598-017-01948-1}},
  volume       = {{7}},
  year         = {{2017}},
}