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Kelley DB. Convergent and divergent neural circuit architectures that support acoustic communication. Front Neural Circuits 2022; 16:976789. [PMID: 36466364 PMCID: PMC9712726 DOI: 10.3389/fncir.2022.976789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 10/19/2022] [Indexed: 11/18/2022] Open
Abstract
Vocal communication is used across extant vertebrates, is evolutionarily ancient, and been maintained, in many lineages. Here I review the neural circuit architectures that support intraspecific acoustic signaling in representative anuran, mammalian and avian species as well as two invertebrates, fruit flies and Hawaiian crickets. I focus on hindbrain motor control motifs and their ties to respiratory circuits, expression of receptors for gonadal steroids in motor, sensory, and limbic neurons as well as divergent modalities that evoke vocal responses. Hindbrain and limbic participants in acoustic communication are highly conserved, while forebrain participants have diverged between anurans and mammals, as well as songbirds and rodents. I discuss the roles of natural and sexual selection in driving speciation, as well as exaptation of circuit elements with ancestral roles in respiration, for producing sounds and driving rhythmic vocal features. Recent technical advances in whole brain fMRI across species will enable real time imaging of acoustic signaling partners, tying auditory perception to vocal production.
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Redaelli L, Galimberti F, Sanvito S. Phenotype constrains the vocal tract in the most dimorphic mammal, the southern elephant seal. CAN J ZOOL 2022. [DOI: 10.1139/cjz-2021-0188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The study of mammal acoustic communication was revolutionized by the application of the source-filter theory, originally developed for human speech. The theory states that the vocal tract is constrained by body anatomy and, therefore, creates a structural link between phenotype and acoustic formants, providing a basis for honest signalling. The phenotype-formants link was validated in many species, but the phenotype-vocal tract link was rarely assessed. We used 2D videogrammetry to estimate the vocal tract length of wild southern elephant seal males (Mirounga leonina Linnaeus, 1758) during their normal vocalization behaviour. We showed that: 1) the vocal tract can be measured non-invasively in a wild large mammal; 2) the vocal tract depends on the structural phenotype (age, body length, and skull size); 3) the nasal tract is more related to the structural phenotype than the buccal tract; 4) the dependence on size, and body length in particular, is stronger than the dependence on age. All together, the phenotypic constraint on vocal tract provides the anatomical basis for honest signalling in elephant seals.
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Affiliation(s)
- Laura Redaelli
- Università degli Studi di Milano, 9304, Dipartimento di Scienze Naturali, Milano, Italy, 20122
| | - Filippo Galimberti
- Elephant Seal Research Group, 263286, Sea Lion Island, FALKLAND, Falkland Islands [Malvinas]
| | - Simona Sanvito
- Elephant Seal Research Group, 263286, Sea Lion Island, FALKLAND, Falkland Islands [Malvinas]
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Beeck VC, Heilmann G, Kerscher M, Stoeger AS. A novel theory of Asian elephant high-frequency squeak production. BMC Biol 2021; 19:121. [PMID: 34134675 PMCID: PMC8210382 DOI: 10.1186/s12915-021-01026-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 04/14/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Anatomical and cognitive adaptations to overcome morpho-mechanical limitations of laryngeal sound production, where body size and the related vocal apparatus dimensions determine the fundamental frequency, increase vocal diversity across taxa. Elephants flexibly use laryngeal and trunk-based vocalizations to form a repertoire ranging from infrasonic rumbles to higher-pitched trumpets. Moreover, they are among the few evolutionarily distantly related animals (humans, pinnipeds, cetaceans, birds) capable of imitating species-atypical sounds. Yet, their vocal plasticity has so far not been related to functions within their natural communicative system, in part because not all call types have been systematically studied. Here, we reveal how Asian elephants (Elephas maximus) produce species-specific squeaks (F0 300-2300 Hz) by using acoustic camera recordings to visualize sound emission and examining this alongside acoustic, behavioral, and morphological data across seven captive groups. RESULTS We found that squeaks were emitted through the closed mouth in synchrony with cheek depression and retraction of the labial angles. The simultaneous emission of squeaks with nasal snorts (biphonation) in one individual confirmed that squeak production was independent of nasal passage involvement and this implicated oral sound production. The squeaks' spectral structure is incongruent with laryngeal sound production and aerodynamic whistles, pointing to tissue vibration as the sound source. Anatomical considerations suggest that the longitudinal closed lips function as the vibrators. Acoustic and temporal parameters exhibit high intra- and inter-individual variability that enables individual but no call-subtype classification. Only 19 of 56 study subjects were recorded to squeak, mostly during alarming contexts and social arousal but some also on command. CONCLUSION Our results strongly suggest that Asian elephants force air from the small oral cavity through the tensed lips, inducing self-sustained lip vibration. Besides human brass players, lip buzzing is not described elsewhere in the animal kingdom. Given the complexity of the proposed mechanism, the surprising absence of squeaking in most of the unrelated subjects and the indication for volitional control, we hypothesize that squeak production involves social learning. Our study offers new insights into how vocal and cognitive flexibility enables mammals to overcome size-related limitations of laryngeal sound production. This flexibility enables Asian elephants to exploit a frequency range spanning seven octaves within their communicative system.
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Affiliation(s)
- Veronika C Beeck
- Department of Behavioural and Cognitive Biology, Mammal Communication Lab, University of Vienna, Vienna, Austria.
| | | | | | - Angela S Stoeger
- Department of Behavioural and Cognitive Biology, Mammal Communication Lab, University of Vienna, Vienna, Austria.
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Nowak LJ. Observations on mechanisms and phenomena underlying underwater and surface vocalisations of grey seals. BIOACOUSTICS 2020. [DOI: 10.1080/09524622.2020.1851298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Lukasz J. Nowak
- Biomedical Photonic Imaging Group, University of Twente, Enschede, The Netherlands
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Boë LJ, Sawallis TR, Fagot J, Badin P, Barbier G, Captier G, Ménard L, Heim JL, Schwartz JL. Which way to the dawn of speech?: Reanalyzing half a century of debates and data in light of speech science. SCIENCE ADVANCES 2019; 5:eaaw3916. [PMID: 32076631 PMCID: PMC7000245 DOI: 10.1126/sciadv.aaw3916] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Accepted: 10/10/2019] [Indexed: 06/10/2023]
Abstract
Recent articles on primate articulatory abilities are revolutionary regarding speech emergence, a crucial aspect of language evolution, by revealing a human-like system of proto-vowels in nonhuman primates and implicitly throughout our hominid ancestry. This article presents both a schematic history and the state of the art in primate vocalization research and its importance for speech emergence. Recent speech research advances allow more incisive comparison of phylogeny and ontogeny and also an illuminating reinterpretation of vintage primate vocalization data. This review produces three major findings. First, even among primates, laryngeal descent is not uniquely human. Second, laryngeal descent is not required to produce contrasting formant patterns in vocalizations. Third, living nonhuman primates produce vocalizations with contrasting formant patterns. Thus, evidence now overwhelmingly refutes the long-standing laryngeal descent theory, which pushes back "the dawn of speech" beyond ~200 ka ago to over ~20 Ma ago, a difference of two orders of magnitude.
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Affiliation(s)
- Louis-Jean Boë
- Université Grenoble Alpes, CNRS, Grenoble INP, Institute of Engineering Univ. Grenoble Alpes, GIPSA-lab, Grenoble, France
| | | | - Joël Fagot
- Brain and Language Research Institute, Aix-Marseille University, Aix-en-Provence, France
- Cognitive Psychology Laboratory, Centre National de la Recherche Scientifique and Aix-Marseille University, Marseille, France
| | - Pierre Badin
- Université Grenoble Alpes, CNRS, Grenoble INP, Institute of Engineering Univ. Grenoble Alpes, GIPSA-lab, Grenoble, France
| | - Guillaume Barbier
- Université Grenoble Alpes, CNRS, Grenoble INP, Institute of Engineering Univ. Grenoble Alpes, GIPSA-lab, Grenoble, France
- School of Speech Pathology and Audiology, Université de Montréal, Montréal, Québec, Canada
| | | | - Lucie Ménard
- Laboratoire de Phonétique, Université du Québec à Montréal, Montréal, Québec, Canada
- Center for Research on Brain, Language, and Music, Montréal, Québec, Canada
| | - Jean-Louis Heim
- Muséum National d'Histoire Naturelle, Paris, France
- Institut de Paléontologie Humaine, Paris, France
| | - Jean-Luc Schwartz
- Université Grenoble Alpes, CNRS, Grenoble INP, Institute of Engineering Univ. Grenoble Alpes, GIPSA-lab, Grenoble, France
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Demartsev V, Gordon N, Barocas A, Bar-Ziv E, Ilany T, Goll Y, Ilany A, Geffen E. The "Law of Brevity" in animal communication: Sex-specific signaling optimization is determined by call amplitude rather than duration. Evol Lett 2019; 3:623-634. [PMID: 31867122 PMCID: PMC6906988 DOI: 10.1002/evl3.147] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 10/10/2019] [Accepted: 10/22/2019] [Indexed: 11/25/2022] Open
Abstract
The efficiency of informational transfer is one of the key aspects of any communication system. The informational coding economy of human languages is often demonstrated by their almost universal fit to Zipf's “Law of Brevity,” expressing negative relationship between word length and its usage frequency. Animal vocal systems, however, provided mixed results in their adherence to this relationship, potentially due to conflicting evolutionary pressures related to differences in signaling range and communicational needs. To examine this potential parallel between human and animal vocal communication, and also to explore how divergent, sex‐specific, communicational settings affect signaling efficiency within a species, we examined the complete vocal repertoire of rock hyraxes (Procavia capensis). As male and female hyraxes differ in their sociality levels and male hyraxes vocal repertoire is dominated by sexual advertisement songs, we hypothesized that sex‐specific vocal repertoires could be subjected to different signaling optimization pressures. Our results show that the sexes differ in repertoire size, call usage, and adherence to coding efficiency principles. Interestingly, the classic call length/call usage relationship is not consistently found in rock hyraxes. Rather, a negative relationship between call amplitude and call usage is found, suggesting that the efficiency of the vocal repertoire is driven by call amplitude rather than duration. We hypothesize that, in contrast to human speech that is mainly intended for short distance, the need for frequent long‐range signaling shapes an animal's vocal repertoire efficiency according to the cost of call amplitude rather than call length. However, call duration may be a secondary factor affecting signaling efficiency, in cases where amplitude is under specific selection pressures, such as sexual selection.
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Affiliation(s)
- Vlad Demartsev
- Department of Biology University of Konstanz Konstanz 78464 Germany.,School of Zoology Tel Aviv University Tel Aviv 6997801 Israel
| | - Naomi Gordon
- School of Zoology Tel Aviv University Tel Aviv 6997801 Israel
| | - Adi Barocas
- San Diego Zoo's Institute for Conservation Research Escondido California 92027.,Wildlife Conservation Research Unit Department of Zoology University of Oxford Abingdon OX13 5QL United Kingdom
| | - Einat Bar-Ziv
- Mitrani Department of Desert Ecology Ben-Gurion University Midreshet Ben-Gurion 8499000 Israel
| | | | - Yael Goll
- School of Zoology Tel Aviv University Tel Aviv 6997801 Israel
| | - Amiyaal Ilany
- Faculty of Life Sciences Bar-Ilan University Ramat-Gan 5290002 Israel
| | - Eli Geffen
- School of Zoology Tel Aviv University Tel Aviv 6997801 Israel
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Ladich F, Winkler H. Acoustic communication in terrestrial and aquatic vertebrates. J Exp Biol 2017; 220:2306-2317. [DOI: 10.1242/jeb.132944] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
ABSTRACT
Sound propagates much faster and over larger distances in water than in air, mainly because of differences in the density of these media. This raises the question of whether terrestrial (land mammals, birds) and (semi-)aquatic animals (frogs, fishes, cetaceans) differ fundamentally in the way they communicate acoustically. Terrestrial vertebrates primarily produce sounds by vibrating vocal tissue (folds) directly in an airflow. This mechanism has been modified in frogs and cetaceans, whereas fishes generate sounds in quite different ways mainly by utilizing the swimbladder or pectoral fins. On land, vertebrates pick up sounds with light tympana, whereas other mechanisms have had to evolve underwater. Furthermore, fishes differ from all other vertebrates by not having an inner ear end organ devoted exclusively to hearing. Comparing acoustic communication within and between aquatic and terrestrial vertebrates reveals that there is no ‘aquatic way’ of sound communication, as compared with a more uniform terrestrial one. Birds and mammals display rich acoustic communication behaviour, which reflects their highly developed cognitive and social capabilities. In contrast, acoustic signaling seems to be the exception in fishes, and is obviously limited to short distances and to substrate-breeding species, whereas all cetaceans communicate acoustically and, because of their predominantly pelagic lifestyle, exploit the benefits of sound propagation in a dense, obstacle-free medium that provides fast and almost lossless signal transmission.
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Affiliation(s)
- Friedrich Ladich
- Department of Behavioural Biology, University of Vienna, Althanstrasse 14, Vienna 1090, Austria
| | - Hans Winkler
- Konrad Lorenz-Institute of Comparative Ethology, Department of Integrative Biology and Evolution, University of Veterinary Medicine, Vienna 1160, Austria
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