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Osiecka AN, Briefer EF, Kidawa D, Żurawska F, Wojczulanis-Jakubas K. Calls of the little auk (Alle alle) chicks reflect their behavioural contexts. PLoS One 2024; 19:e0299033. [PMID: 38394184 PMCID: PMC10889865 DOI: 10.1371/journal.pone.0299033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 02/02/2024] [Indexed: 02/25/2024] Open
Abstract
Animal vocalisations can often inform conspecifics about the behavioural context of production and the underlying affective states, hence revealing whether a situation should be approached or avoided. While this is particularly important for socially complex species, little is known about affective expression in wild colonial animals, and even less to about their young. We studied vocalisations of the little auk (Alle alle) chicks in the Hornsund breeding colony, Svalbard. Little auks are highly colonial seabirds, and adults convey complex behavioural contexts through their calls. We recorded chick calls during two contexts of opposite affective valence: handing by a human, and while they interact with their parents inside the nest. Using permuted discriminant function analysis and a series of linear mixed models, we examined the effect of the production context/associated affective valence on the acoustic parameters of those calls. Calls were reliably classified to their context, with over 97% accuracy. Calls uttered during handling had higher mean entropy, fundamental frequency, as well as lower spectral centre of gravity and a less steep spectral slope compared to calls produced during interactions with a parent inside the nest. The individuality of handling calls, assessed by information content, was lower than the individuality of calls uttered in the nest. These findings suggest that seabird chicks can effectively communicate behavioural/affective contexts through calls, conveying socially important messages early in development. Our results are mostly in line with emotional expression patterns observed across taxa, supporting their evolutionary continuity.
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Affiliation(s)
- Anna N. Osiecka
- Department of Vertebrate Ecology and Zoology, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
- Behavioural Ecology Group, Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Elodie F. Briefer
- Behavioural Ecology Group, Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Dorota Kidawa
- Department of Vertebrate Ecology and Zoology, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Feliksa Żurawska
- Department of Vertebrate Ecology and Zoology, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
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2
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Martin K, Cornero FM, Clayton NS, Adam O, Obin N, Dufour V. Vocal complexity in a socially complex corvid: gradation, diversity and lack of common call repertoire in male rooks. ROYAL SOCIETY OPEN SCIENCE 2024; 11:231713. [PMID: 38204786 PMCID: PMC10776222 DOI: 10.1098/rsos.231713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 12/08/2023] [Indexed: 01/12/2024]
Abstract
Vocal communication is widespread in animals, with vocal repertoires of varying complexity. The social complexity hypothesis predicts that species may need high vocal complexity to deal with complex social organization (e.g. have a variety of different interindividual relations). We quantified the vocal complexity of two geographically distant captive colonies of rooks, a corvid species with complex social organization and cognitive performances, but understudied vocal abilities. We quantified the diversity and gradation of their repertoire, as well as the inter-individual similarity at the vocal unit level. We found that males produced call units with lower diversity and gradation than females, while song units did not differ between sexes. Surprisingly, while females produced highly similar call repertoires, even between colonies, each individual male produced almost completely different call repertoires from any other individual. These findings question the way male rooks communicate with their social partners. We suggest that each male may actively seek to remain vocally distinct, which could be an asset in their frequently changing social environment. We conclude that inter-individual similarity, an understudied aspect of vocal repertoires, should also be considered as a measure of vocal complexity.
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Affiliation(s)
- Killian Martin
- PRC, UMR 7247, Ethologie Cognitive et Sociale, CNRS-IFCE-INRAE-Université de Tours, Strasbourg, France
| | | | | | - Olivier Adam
- Institut Jean Le Rond d'Alembert, UMR 7190, CNRS-Sorbonne Université, 75005 Paris, France
- Institut des Neurosciences Paris-Saclay, UMR 9197, CNRS-Université Paris Sud, Orsay, France
| | - Nicolas Obin
- STMS Lab, IRCAM, CNRS-Sorbonne Université, Paris, France
| | - Valérie Dufour
- PRC, UMR 7247, Ethologie Cognitive et Sociale, CNRS-IFCE-INRAE-Université de Tours, Strasbourg, France
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3
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Smeele SQ, Senar JC, Aplin LM, McElreath MB. Evidence for vocal signatures and voice-prints in a wild parrot. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230835. [PMID: 37800160 PMCID: PMC10548090 DOI: 10.1098/rsos.230835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 09/04/2023] [Indexed: 10/07/2023]
Abstract
In humans, identity is partly encoded in a voice-print that is carried across multiple vocalizations. Other species also signal vocal identity in calls, such as shown in the contact call of parrots. However, it remains unclear to what extent other call types in parrots are individually distinct, and whether there is an analogous voice-print across calls. Here we test if an individual signature is present in other call types, how stable this signature is, and if parrots exhibit voice-prints across call types. We recorded 5599 vocalizations from 229 individually marked monk parakeets (Myiopsitta monachus) over a 2-year period in Barcelona, Spain. We examined five distinct call types, finding evidence for an individual signature in three. We further show that in the contact call, while birds are individually distinct, the calls are more variable than previously assumed, changing over short time scales (seconds to minutes). Finally, we provide evidence for voice-prints across multiple call types, with a discriminant function being able to predict caller identity across call types. This suggests that monk parakeets may be able to use vocal cues to recognize conspecifics, even across vocalization types and without necessarily needing active vocal signatures of identity.
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Affiliation(s)
- Simeon Q. Smeele
- Cognitive and Cultural Ecology Research Group, Max Planck Institute of Animal Behavior, Radolfzell, Germany
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Department of Biology, University of Konstanz, Konstanz, Germany
| | | | - Lucy M. Aplin
- Cognitive and Cultural Ecology Research Group, Max Planck Institute of Animal Behavior, Radolfzell, Germany
- Department of Evolutionary Biology and Environmental Science, University of Zurich, Zurich, Switzerland
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, Australia
| | - Mary Brooke McElreath
- Cognitive and Cultural Ecology Research Group, Max Planck Institute of Animal Behavior, Radolfzell, Germany
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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4
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Freiler MK, Smith GT. Neuroendocrine mechanisms contributing to the coevolution of sociality and communication. Front Neuroendocrinol 2023; 70:101077. [PMID: 37217079 PMCID: PMC10527162 DOI: 10.1016/j.yfrne.2023.101077] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 04/19/2023] [Accepted: 05/15/2023] [Indexed: 05/24/2023]
Abstract
Communication is inherently social, so signaling systems should evolve with social systems. The 'social complexity hypothesis' posits that social complexity necessitates communicative complexity and is generally supported in vocalizing mammals. This hypothesis, however, has seldom been tested outside the acoustic modality, and comparisons across studies are confounded by varying definitions of complexity. Moreover, proximate mechanisms underlying coevolution of sociality and communication remain largely unexamined. In this review, we argue that to uncover how sociality and communication coevolve, we need to examine variation in the neuroendocrine mechanisms that coregulate social behavior and signal production and perception. Specifically, we focus on steroid hormones, monoamines, and nonapeptides, which modulate both social behavior and sensorimotor circuits and are likely targets of selection during social evolution. Lastly, we highlight weakly electric fishes as an ideal system in which to comparatively address the proximate mechanisms underlying relationships between social and signal diversity in a novel modality.
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Affiliation(s)
- Megan K Freiler
- Department of Biology, Indiana University, Bloomington, IN, United States; Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN, United States.
| | - G Troy Smith
- Department of Biology, Indiana University, Bloomington, IN, United States; Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN, United States
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5
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Arnaud V, Pellegrino F, Keenan S, St-Gelais X, Mathevon N, Levréro F, Coupé C. Improving the workflow to crack Small, Unbalanced, Noisy, but Genuine (SUNG) datasets in bioacoustics: The case of bonobo calls. PLoS Comput Biol 2023; 19:e1010325. [PMID: 37053268 PMCID: PMC10129004 DOI: 10.1371/journal.pcbi.1010325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 04/25/2023] [Accepted: 03/01/2023] [Indexed: 04/15/2023] Open
Abstract
Despite the accumulation of data and studies, deciphering animal vocal communication remains challenging. In most cases, researchers must deal with the sparse recordings composing Small, Unbalanced, Noisy, but Genuine (SUNG) datasets. SUNG datasets are characterized by a limited number of recordings, most often noisy, and unbalanced in number between the individuals or categories of vocalizations. SUNG datasets therefore offer a valuable but inevitably distorted vision of communication systems. Adopting the best practices in their analysis is essential to effectively extract the available information and draw reliable conclusions. Here we show that the most recent advances in machine learning applied to a SUNG dataset succeed in unraveling the complex vocal repertoire of the bonobo, and we propose a workflow that can be effective with other animal species. We implement acoustic parameterization in three feature spaces and run a Supervised Uniform Manifold Approximation and Projection (S-UMAP) to evaluate how call types and individual signatures cluster in the bonobo acoustic space. We then implement three classification algorithms (Support Vector Machine, xgboost, neural networks) and their combination to explore the structure and variability of bonobo calls, as well as the robustness of the individual signature they encode. We underscore how classification performance is affected by the feature set and identify the most informative features. In addition, we highlight the need to address data leakage in the evaluation of classification performance to avoid misleading interpretations. Our results lead to identifying several practical approaches that are generalizable to any other animal communication system. To improve the reliability and replicability of vocal communication studies with SUNG datasets, we thus recommend: i) comparing several acoustic parameterizations; ii) visualizing the dataset with supervised UMAP to examine the species acoustic space; iii) adopting Support Vector Machines as the baseline classification approach; iv) explicitly evaluating data leakage and possibly implementing a mitigation strategy.
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Affiliation(s)
- Vincent Arnaud
- Département des arts, des lettres et du langage, Université du Québec à Chicoutimi, Chicoutimi, Canada
- Laboratoire Dynamique Du Langage, UMR 5596, Université de Lyon, CNRS, Lyon, France
| | - François Pellegrino
- Laboratoire Dynamique Du Langage, UMR 5596, Université de Lyon, CNRS, Lyon, France
| | - Sumir Keenan
- ENES Bioacoustics Research Laboratory, University of Saint Étienne, CRNL, CNRS UMR 5292, Inserm UMR_S 1028, Saint-Étienne, France
| | - Xavier St-Gelais
- Département des arts, des lettres et du langage, Université du Québec à Chicoutimi, Chicoutimi, Canada
| | - Nicolas Mathevon
- ENES Bioacoustics Research Laboratory, University of Saint Étienne, CRNL, CNRS UMR 5292, Inserm UMR_S 1028, Saint-Étienne, France
| | - Florence Levréro
- ENES Bioacoustics Research Laboratory, University of Saint Étienne, CRNL, CNRS UMR 5292, Inserm UMR_S 1028, Saint-Étienne, France
| | - Christophe Coupé
- Laboratoire Dynamique Du Langage, UMR 5596, Université de Lyon, CNRS, Lyon, France
- Department of Linguistics, The University of Hong Kong, Hong Kong, China
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6
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Rookognise: Acoustic detection and identification of individual rooks in field recordings using multi-task neural networks. ECOL INFORM 2022. [DOI: 10.1016/j.ecoinf.2022.101818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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7
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Selection levels on vocal individuality: strategic use or byproduct. Curr Opin Behav Sci 2022. [DOI: 10.1016/j.cobeha.2022.101140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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8
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Individuality in Roars of Black-and-Gold Howler Monkeys (Alouatta caraya). INT J PRIMATOL 2022. [DOI: 10.1007/s10764-022-00290-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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9
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Cornec C, Ngofuna M, Lemasson A, Monghiemo C, Narat V, Levréro F. A pilot study of calling patterns and vocal turn-taking in wild bonobos Pan paniscus. ETHOL ECOL EVOL 2022. [DOI: 10.1080/03949370.2022.2044387] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Clément Cornec
- Université Jean Monnet de Saint Étienne, CNRS, Équipe Neuro-Éthologie Sensorielle, ENES/CRNL UMR 5292, INSERM UMR_S 1028, Saint-Étienne, France
| | | | - Alban Lemasson
- Éthologie Animale et Humaine, Université de Rennes/Université de Normandie, CNRS, EthoS – UMR 6552, Rennes, France
- Institut Universitaire de France, Paris, France
| | | | - Victor Narat
- Éco-Anthropologie, CNRS/MNHN/Université de Paris, France
| | - Florence Levréro
- Université Jean Monnet de Saint Étienne, CNRS, Équipe Neuro-Éthologie Sensorielle, ENES/CRNL UMR 5292, INSERM UMR_S 1028, Saint-Étienne, France
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10
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Pougnault L, Levréro F, Leroux M, Paulet J, Bombani P, Dentressangle F, Deruti L, Mulot B, Lemasson A. Social pressure drives "conversational rules" in great apes. Biol Rev Camb Philos Soc 2021; 97:749-765. [PMID: 34873806 DOI: 10.1111/brv.12821] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 11/19/2021] [Accepted: 11/25/2021] [Indexed: 01/07/2023]
Abstract
In the last decade, two hypotheses, one on the evolution of animal vocal communication in general and the other on the origins of human language, have gained ground. The first hypothesis argues that the complexity of communication co-evolved with the complexity of sociality. Species forming larger groups with complex social networks have more elaborate vocal repertoires. The second hypothesis posits that the core of communication is represented not only by what can be expressed by an isolated caller, but also by the way that vocal interactions are structured, language being above all a social act. Primitive forms of conversational rules based on a vocal turn-taking principle are thought to exist in primates. To support and bring together these hypotheses, more comparative studies of socially diverse species at different levels of the primate phylogeny are needed. However, the majority of available studies focus on monkeys, primates that are distant from the human lineage. Great apes represent excellent candidates for such comparative studies because of their phylogenetic proximity to humans and their varied social lives. We propose that studying vocal turn-taking in apes could address several major gaps regarding the social relevance of vocal turn-taking and the evolutionary trajectory of this behaviour among anthropoids. Indeed, how the social structure of a species may influence the vocal interaction patterns observed among group members remains an open question. We gathered data from the literature as well as original unpublished data (where absent in the literature) on four great ape species: chimpanzees Pan troglodytes, bonobos Pan paniscus, western lowland gorillas Gorilla gorilla gorilla and Bornean orang-utans Pongo pygmaeus. We found no clear-cut relationship between classical social complexity metrics (e.g. number of group members, interaction rates) and vocal complexity parameters (e.g. repertoire size, call rates). Nevertheless, the nature of the society (i.e. group composition, diversity and valence of social bonds) and the type of vocal interaction patterns (isolated calling, call overlap, turn-taking-based vocal exchanges) do appear to be related. Isolated calling is the main vocal pattern found in the species with the smallest social networks (orang-utan), while the other species show vocal interactions that are structured according to temporal rules. A high proportion of overlapping vocalisations is found in the most competitive species (chimpanzee), while vocal turn-taking predominates in more tolerant bonobos and gorillas. Also, preferentially interacting individuals and call types used to interact are not randomly distributed. Vocal overlap ('chorusing') and vocal exchange ('conversing') appear as possible social strategies used to advertise/strengthen social bonds. Our analyses highlight that: (i) vocal turn-taking is also observed in non-human great apes, revealing universal rules for conversing that may be deeply rooted in the primate lineage; (ii) vocal interaction patterns match the species' social lifestyle; (iii) although limited to four species here, adopting a targeted comparative approach could help to identify the multiple and subtle factors underlying social and vocal complexity. We believe that vocal interaction patterns form the basis of a promising field of investigation that may ultimately improve our understanding of the socially driven evolution of communication.
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Affiliation(s)
- Loïc Pougnault
- Univ Rennes, Normandie Univ, CNRS, EthoS (Éthologie animale et humaine) - UMR 6552, 263 avenue du Général Leclerc, Rennes, 35042, France.,Université de Lyon/Saint-Etienne, CNRS, Equipe Neuro-Ethologie Sensorielle, ENES/CRNL, UMR5292, INSERM UMR_S 1028, 23 rue Paul Michelon, Saint-Etienne, 42023, France.,ZooParc de Beauval & Beauval Nature, Avenue du Blanc, Saint Aignan, 41110, France
| | - Florence Levréro
- Université de Lyon/Saint-Etienne, CNRS, Equipe Neuro-Ethologie Sensorielle, ENES/CRNL, UMR5292, INSERM UMR_S 1028, 23 rue Paul Michelon, Saint-Etienne, 42023, France
| | - Maël Leroux
- Department of Comparative Linguistics, University of Zürich, Thurgauerstrasse 30, Zürich-Oerlikon, 8050, Switzerland.,Budongo Conservation Field Station, Masindi, Uganda.,Center for the Interdisciplinary Study of Language Evolution (ISLE), University of Zürich, Plattenstrasse 54, Zürich, 8032, Switzerland
| | - Julien Paulet
- Univ Rennes, Normandie Univ, CNRS, EthoS (Éthologie animale et humaine) - UMR 6552, 263 avenue du Général Leclerc, Rennes, 35042, France
| | - Pablo Bombani
- NGO Mbou-Mon-Tour, Nkala, Territoire de Bolodo, Maï-Ndombe, Democratic Republic of the Congo
| | - Fabrice Dentressangle
- Université de Lyon/Saint-Etienne, CNRS, Equipe Neuro-Ethologie Sensorielle, ENES/CRNL, UMR5292, INSERM UMR_S 1028, 23 rue Paul Michelon, Saint-Etienne, 42023, France
| | - Laure Deruti
- Université de Lyon/Saint-Etienne, CNRS, Equipe Neuro-Ethologie Sensorielle, ENES/CRNL, UMR5292, INSERM UMR_S 1028, 23 rue Paul Michelon, Saint-Etienne, 42023, France
| | - Baptiste Mulot
- ZooParc de Beauval & Beauval Nature, Avenue du Blanc, Saint Aignan, 41110, France
| | - Alban Lemasson
- Univ Rennes, Normandie Univ, CNRS, EthoS (Éthologie animale et humaine) - UMR 6552, 263 avenue du Général Leclerc, Rennes, 35042, France.,Institut Universitaire de France, 1 rue Descartes, Paris, 75231, France
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11
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Mercado E, Perazio CE. All units are equal in humpback whale songs, but some are more equal than others. Anim Cogn 2021; 25:149-177. [PMID: 34363127 DOI: 10.1007/s10071-021-01539-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 07/13/2021] [Accepted: 07/21/2021] [Indexed: 11/28/2022]
Abstract
Flexible production and perception of vocalizations is linked to an impressive array of cognitive capacities including language acquisition by humans, song learning by birds, biosonar in bats, and vocal imitation by cetaceans. Here, we characterize a portion of the repertoire of one of the most impressive vocalizers in nature: the humpback whale. Qualitative and quantitative analyses of sounds (units) produced by humpback whales revealed that singers gradually morphed streams of units along multiple acoustic dimensions within songs, maintaining the continuity of spectral content across subjectively dissimilar unit "types." Singers consistently produced some unit forms more frequently and intensely than others, suggesting that units are functionally heterogeneous. The precision with which singing humpback whales continuously adjusted the acoustic characteristics of units shows that they possess exquisite vocal control mechanisms and vocal flexibility beyond what is seen in most animals other than humans. The gradual morphing of units within songs that we observed is inconsistent with past claims that humpback whales construct songs from a fixed repertoire of discrete unit types. These findings challenge the results of past studies based on fixed-unit classification methods and argue for the development of new metrics for characterizing the graded structure of units. The specific vocal variations that singers produced suggest that humpback whale songs are unlikely to provide detailed information about a singer's reproductive fitness, but can reveal the precise locations and movements of singers from long distances and may enhance the effectiveness of units as sonar signals.
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Affiliation(s)
- Eduardo Mercado
- Department of Psychology, University at Buffalo, The State University of New York, Park Hall, Buffalo, NY, 14260, USA.
| | - Christina E Perazio
- Department of Psychology, University at Buffalo, The State University of New York, Park Hall, Buffalo, NY, 14260, USA.,School of Social and Behavioral Sciences, University of New England, Biddeford, ME, USA
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12
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Lesser spot-nosed monkeys coordinate alarm call production with associated Campbell’s monkeys. Behav Ecol Sociobiol 2021. [DOI: 10.1007/s00265-021-03053-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Abstract
Forest monkeys often form semi-permanent mixed-species associations to increase group-size related anti-predator benefits without corresponding increases in resource competition. In this study, we analysed the alarm call system of lesser spot-nosed monkeys, a primate that spends most of its time in mixed-species groups while occupying the lowest and presumably most dangerous part of the forest canopy. In contrast to other primate species, we found no evidence for predator-specific alarm calls. Instead, males gave one general alarm call type (‘kroo’) to three main dangers (i.e., crowned eagles, leopards and falling trees) and a second call type (‘tcha-kow’) as a coordinated response to calls produced in non-predatory contexts (‘boom’) by associated male Campbell’s monkeys. Production of ‘kroo’ calls was also strongly affected by the alarm calling behaviour of male Campbell’s monkeys, suggesting that male lesser spot-nosed monkeys adjust their alarm call production to another species’ vocal behaviour. We discuss different hypotheses for this unusual phenomenon and propose that high predation pressure can lead to reliance on other species vocal behaviour to minimise predation.
Significance statement
Predation can lead to the evolution of acoustically distinct, predator-specific alarm calls. However, there are occasional reports of species lacking such abilities, despite diverse predation pressure, suggesting that evolutionary mechanisms are more complex. We conducted field experiments to systematically describe the alarm calling behaviour of lesser spot-nosed monkeys, an arboreal primate living in the lower forest strata where pressure from different predators is high. We found evidence for two acoustically distinct calls but, contrary to other primates in the same habitat, no evidence for predator-specific alarms. Instead, callers produced one alarm call type (‘kroo’) to all predator classes and another call type (‘tcha-kow’) to non-predatory dangers, but only as a response to a specific vocalisation of Campbell’s monkeys (‘boom’). The production of both calls was affected by the calling behaviour of Campbell’s monkeys, suggesting that lesser spot-nosed monkey vocal behaviour is dependent on the antipredator behaviour of other species. Our study advances the theory of interspecies interactions and evolution of alarm calls.
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13
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Tokuyama N, Toda K, Poiret ML, Iyokango B, Bakaa B, Ishizuka S. Two wild female bonobos adopted infants from a different social group at Wamba. Sci Rep 2021; 11:4967. [PMID: 33737517 PMCID: PMC7973529 DOI: 10.1038/s41598-021-83667-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 02/05/2021] [Indexed: 11/09/2022] Open
Abstract
Adoption, the act of taking another individual's offspring and treating it as one's own, is rare but widely observed in various mammal species and may increase the survival of adoptees. Adoption may also benefit adoptive mothers, for example they might care for close kin to gain indirect fitness or to learn caregiving behaviours. Here, we report two cases of a wild bonobo adopting an infant from a different social group, the first report of cross-group adoption in great apes. In one case, the adoptive mother was already a mother of two dependent offspring. In the other case, the adoptive mother was an old parous female whose own offspring had already emigrated into a different social group. The adoptive mothers provided various maternal care to the adoptees, such as carrying, grooming, nursing, and sharing food. No aggression was observed by group members towards the out-group adoptees. In both cases, adoptees had no maternal kin-relationship with their adoptive mothers. Both adoptive mothers already had experience of rearing their own offspring. Instead, these cases of adoption may have been driven by other evolutionary adaptive traits of bonobos, such as their strong attraction to infants and high tolerance towards immatures and out-group individuals.
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Affiliation(s)
- Nahoko Tokuyama
- Primate Research Institute, Kyoto University, Kanrin 41, Inuyama, Aichi, 484-8506, Japan.
- Wildlife Research Center, Kyoto University, Kyoto, Japan.
| | - Kazuya Toda
- Primate Research Institute, Kyoto University, Kanrin 41, Inuyama, Aichi, 484-8506, Japan
| | | | - Bahanande Iyokango
- Research Center for Ecology and Forestry, Mabali, Mbandaka, Democratic Republic of the Congo
| | - Batuafe Bakaa
- Research Center for Ecology and Forestry, Mabali, Mbandaka, Democratic Republic of the Congo
| | - Shintaro Ishizuka
- Primate Research Institute, Kyoto University, Kanrin 41, Inuyama, Aichi, 484-8506, Japan
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