Hidden in plain sound: the scientific potential of house mouse squeaks

Abstract

The house mouse (Mus musculus) is an emerging model organism for the study of vocal communication. While mice emit a diversity of calls, most publications on adult mouse vocalizations primarily focus on ultrasonic vocalizations and only a small proportion include other vocalizations, like squeaks. The representation of squeaks in the literature is not an accurate reflection of their behavioural prevalence, however. Squeaks are common features of the mouse vocal repertoire, emitted under a range of circumstances. In this review, we synthesize the available evidence on mouse squeaks, demonstrating that squeaks are social vocalizations. Although their presence in social situations is evident, the extent to which squeaks convey information about the vocalizer and affect listener behaviour across different social contexts has yet to be thoroughly studied. Exploring the nuanced social functions of squeaks and correcting the publication bias that favours ultrasonic vocalizations will require a coordinated research effort, and we provide several recommendations for meeting these goals. Finally, we highlight the potential of the mouse squeak as an instrument for research beyond ethology, including to investigate the neural basis of vocal communication and conditions that impact communication in humans.

Keywords: Mus musculus; autism spectrum disorder; squeak; ultrasonic vocalization; vocal communication.

Figure 1.

(a) Spectrograms of squeaks depicting the presence or absence of nonlinear phenomena: subharmonics and deterministic chaos. Arrows indicate nonlinearities (adapted from [10]). (b) Spectrogram of mid-frequency vocalizations [11]. (c) Spectrograms of ultrasonic vocalizations (USVs) showing harmonic and non-harmonic USVs (adapted from [12] and used with permission). (d) The relative prevalence of publications on the different adult house mouse vocalizations are depicted in panels (a–c). (e) The number of publications (per year) that include USVs (blue line) and squeaks (orange) over time, illustrating an increase in USV-focused publications after 2005 (arrow).

Figure 2.

(a) Female squeak production is higher at the beginning of mixed-sex interactions in which mounting did not occur (black bars) compared to interactions in which mounting did occur (open bars) (adapted from [10]). (b) USV emission by male mice is significantly lower during female squeak playback compared to the preceding baseline period with no playback [59]. (c) USV emission by male mice (black line) is quickly suppressed by female squeak playback (grey shading), but rapidly recovers during silent periods (adapted from [59]). (d) Female squeaking rate is significantly greater in time-bins surrounding mounting incidences (peri-mounting) compared to non-mounting time-bins (adapted from [10]). (e) Female squeak structure changes across the oestrous cycle. Unlike linear portions of squeaks (left panel), nonlinear segment duration significantly increases during oestrus compared to dioestrus (right panel) [10].

Figure 3.

Conceptual diagram depicting functional hypotheses for mouse squeaks.