DOI: 10.5061/dryad.d51c5b0dr
title: The “silent” half: diversity, function, and the critical knowledge gap on female frog vocalizations

description: Anuran vocalizations are crucial for species recognition and social
 interactions, particularly in reproduction. Historically, research has
 focused almost exclusively on male calls, leading to a male-biased
 perspective in anuran bioacoustics. Female calls have often been neglected
 due to their softness, making them difficult to detect. This review
 provides an overview of female calling behavior in anurans, addressing a
 critical gap in frog bioacoustics and sexual selection. Specifically, we
 aim to 1) provide an overview of the current state of knowledge of female
 calling in frogs; 2) propose a standardized classification for anuran call
 types; 3) identify general patterns and challenges; 4) recommend best
 practices; and 5) highlight areas for further exploration. Our literature
 review indicates that female calls have been documented in 112 species
 across 53 genera and 29 families, representing approximately 1.43% of all
 described anuran species. However, most descriptions are anecdotal or
 purely descriptive, with few functional analyses. Our findings underscore
 the widespread but largely overlooked presence of calling females in
 anurans. Expanding our research efforts on female vocalizations will
 improve our understanding of anuran communication. We hope this review
 motivates researchers to consider female frogs in future behavioral,
 ecological, and evolutionary studies.
description: (a) Literature review We conducted a
 systematic literature review to identify studies on female calling
 behavior in amphibians beginning in July 2023 (Supplementary Material S1).
 We included peer-reviewed documents, including journal articles, theses,
 and conference abstracts (excluding preprints). Our search strategy
 included initial broad exploratory searches with subsequent targeted
 searches to maximize coverage while filtering irrelevant results. We used
 two primary databases: Google Scholar and Web of Science (WOS). Initial
 searches combined the term ‘amphibia’ with one or more of the following:
 ‘female vocalization,’ ‘female courtship call,’ ‘female reciprocal call,’
 ‘female acoustic response,’ ‘female vocal interaction,’ ‘female mating
 vocalization,’ or ‘female call’. These returned 435 results in Google
 Scholar and 25,280 in WOS.  Next, we conducted a more
 targeted search within WOS, adding the terms: ‘Anura’ OR ‘amphibian’
 combined with ‘calling female’ OR ‘female acoustic response’ OR ‘female
 vocal interaction’ OR ‘female mating vocalization.’ To reduce irrelevant
 results, we excluded the terms ‘mammal’ and ‘bird.’ We also applied
 subject area exclusionary filters (i.e., subject categories not related to
 Zoology, Animal Ecology, Behavioral Sciences, Ecology, Biology,
 Evolutionary Biology, Neuroscience, and Reproductive Biology). This
 yielded 2,271 documents as of November 2024. We
 supplemented these results by conducting backward and forward citation
 searches in Google Scholar using three key review papers on female anuran
 vocalizations (references [40,46,47]). Forward citation searches involved
 screening all articles citing these reviews. Backward citation searching
 involved examining the reference lists of the reviews to identify earlier
 relevant studies. Combining these results with those from the initial
 Google Scholar and WOS searches yielded 2,919 documents. We screened the
 titles and abstracts of all retrieved documents to assess relevance.
 Studies that explicitly mentioned female calls or showed potential to
 include relevant information (e.g., focusing on amphibian ecology,
 behavior, physiology, or bioacoustics) were read in full. To be included
 in our dataset, a source had to contain direct observations, spectrograms,
 or detailed descriptions of female vocalizations. We also included sources
 in French, German, Portuguese, and Spanish. This process yielded 90
 records. For relevant cases within this set, we conducted additional
 backward and forward citation searches and identified 18 studies not
 captured by the initial search. Our final dataset comprised 108 documents.
 Data were compiled in a standardized spreadsheet with taxonomic names
 checked and duplicates removed (Supplementary Material S2). The search
 concluded in November 2024. (b) Data extraction and
 family-level mapping We compiled the data on female
 calls from the publications that specifically reported females calling.
 For each study, we extracted the species name, the type of call as defined
 by the authors, the description of the female call (if available), and any
 ecological or behavioral contextual information about the vocalization. We
 also recorded whether the authors conducted experiments or behavioral
 assays to test the function of the female call. Then, we compared the
 female call definitions from the original studies to our proposed
 definitions. Whenever our classification differed from the reported one,
 we emphasized that our assignments relied solely on the authors'
 information, without making any inferences beyond what was explicitly
 stated To standardize the data, we coded instances of
 spontaneous calling, researcher manipulation (i.e., handling or physical
 restraint), and tests of functional significance as binary variables (yes
 = 1, no = 0). When information was unavailable, we designated it as NA
 (Not Available). All extracted information was then organized and
 summarized in a table (Supplementary Material S2). We mapped the different
 types of female calls onto a consensus amphibian phylogenetic tree [48],
 which includes 54 extant anuran families. To account for cases where
 female calling was reported but lacked sufficient detail to classify the
 call type, we included a 'No detail' category.
 We recorded 132 instances of female calling behavior across 112
 species (53 genera, 29 families) from all the studies examined for this
 review. This represents approximately 1.43% of all described anuran
 species. Female calling behavior in frogs is widespread across the
 phylogeny (Figure 3), occurring in both deeply divergent families like
 Bombinatoridae and Leiopelmatidae, as well as in more recently diverged
 families such as Craugastoridae and Rhacophoridae. Ranidae is the family
 with the greatest number of species (18 species), followed by Hylidae (15
 species), Leptodactylidae (14 species), and Eleutherodactylidae (10
 species). At the genus level, Leptodactylus has the highest number of
 species with female calls, with 12 species, followed closely by
 Eleutherodactylus with 10 species, and Xenopus with eight species reported
 to produce female calls. We want to emphasize that the lack of records of
 female calls in certain families or genera does not necessarily indicate
 the absence of this behavior. Instead, it reflects the insufficient
 knowledge of basic natural history and the lack of efforts in
 investigating female calling behavior in frogs.
description: # The “silent” half: diversity, function, and the critical knowledge gap
 on female frog vocalizations ## Provenance for this README * File name:
 README.md * Authors: Erika M. Santana, Angela M Mendoza-Henao, and Johana
 Goyes Vallejos * Date created: 2024-02-17 * Date modified: 2024-04-28 ##
 Dataset Version and Release History * Current Version: * Number: 1.0.0 *
 Date: 2024-04-28 ## Dataset Attribution and Usage * Dataset Title: Data
 for the article "The “silent” half: diversity, function, and the
 critical knowledge gap on female frog vocalizations" * Persistent
 Identifier: [https://doi.org/10.5061/dryad.d51c5b0dr](https://doi.org/10.5061/dryad.d51c5b0dr) * License: Use of these data is covered by the following license: * Title: CC0 1.0 Universal (CC0 1.0) * Specification: [Https://Creativecommons.Org/Publicdomain/Zero/1.0/](Https://Creativecommons.Org/Publicdomain/Zero/1.0/) * Suggested Citations: * Dataset citation: Santana, Erika M.; Mendoza-Henao, Angela M.; Goyes Vallejos, Johana (Forthcoming 2025). The “silent” half: diversity, function, and the critical knowledge gap on female frog vocalizations [Dataset]. Dryad. [https://doi.org/10.5061/dryad.d51c5b0dr](https://doi.org/10.5061/dryad.d51c5b0dr) * Corresponding publication: Santana Erika Marques, Mendoza-Henao Angela M. and Goyes Vallejos Johana. 2025. The “silent” half: diversity, function, and the critical knowledge gap on female frog vocalizations. *Proc. R. Soc. B.* [https://doi.org/10.1098/rspb.2025.0454](https://doi.org/10.1098/rspb.2025.0454) ## Contact Information * Name: Erika M. Santana * Affiliations: Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil * Email: [erika.ms@gmail.com](mailto:erika.ms@gmail.com) * Alternate Email: [erika.ms@alumni.usp.br](mailto:erika.ms@alumni.usp.br) --- # Additional Dataset Metadata ## Acknowledgements * Funding sources: EMS is currently supported by a Postdoctoral Fellowship Grant from the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, grant number 2024/12435-6) as part of the São Paulo Excellence Chair Project (SPEC) entitled “Innovations in Human and Non-Human Communities” (FAPESP grant number 2018/18900-1). JGV was supported by the Division of Biological Sciences at the University of Missouri-Columbia. ## Dates and Locations * Data has been compiled from previously published sources that are cited in the data file. Please see "Supplementary_Material_S2b_references.csv" --- # Data and File Overview We have submitted the currently available data on female frog vocalizations reported in the literature. The file *Supplementary_Material_S2a_dataset.csv* contains 132 instances of female calling behavior. The file *Supplementary_Material_S2b_references.csv* lists the literature sources from which each instance was collected. # Descriptions #### *Supplementary\_Material\_S2a\_dataset.csv* * *family*: Taxonomic family of the species. * *genus*: Taxonomic genus of the species.  * *species*: Species name * *spontaneous*: Classification of call spontaneity, coded as 1 when the call is emitted spontaneously, 0 when the call is emitted following any type of stimulus, and NA when no information is available. * *researcher_manipulation*: Classification of calls according to the type of research manipulation (including handling, restraint, hormone induction, and more brutal methods like shaking the plastic bags or smacking the frog’s headt), coded as 1 when the call is emitted after research manipulation, 0 when the call is emitted without research manipulation, and NA when no information is available. * *type_(original)*: Call type classification according to the original paper from which the data were collected. * *type_(this_study)*: Call type classification according to the system we propose in the current paper. * *match*: Comparison between the call type attributed by the original source and our classification, coded as 1 when there was a match, 0 when the call type attributed by the original source differed from our classification, and NA when there was not enough information to classify one of the call types. * *function_tested*: Classification of calls based on the presence or absence of any experimental assessment of function (e.g., behavioral experiments or playback tests), coded as 1 when functional tests were conducted, 0 when no functional tests were conducted, and NA when there was not enough information to assign a classification. * *references*: Citation of the literature source from which the information was collected. #### *Supplementary\_Material\_S2b\_references.csv* List of full bibliographic references corresponding to the citations provided in the "references" column of the dataset *Supplementary_Material_S2a_dataset.csv*. --- END OF README