The “silent” half: diversity, function, and the critical knowledge gap on female frog vocalizations

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.