Mechanisms of sound production in deer mice (Peromyscus spp.)

Abstract

Rodent diversification is associated with a large diversity of species-specific social vocalizations generated by two distinct laryngeal sound production mechanisms- whistling and airflow-induced vocal fold vibration. Understanding the relative importance of each modality to context-dependent acoustic interactions requires comparative analyses among closely related species. In this study, we used light gas experiments, acoustic analyses, and laryngeal morphometrics to identify the distribution of the two mechanisms among six species of deer mice (Peromyscus). We found that high frequency vocalizations (simple and complex sweeps) produced in close-distance contexts were generated by a whistle mechanism. In contrast, lower frequency sustained vocalizations (SVs) used in longer distance communication were produced by airflow-induced vocal fold vibrations. Pup isolation calls, which resemble adult SVs, were also produced by airflow-induced vocal fold vibrations. Nonlinear phenomena (NLP) were common in adult SVs and pup isolation calls, suggesting irregular vocal fold vibration characteristics. Both vocal production mechanisms were facilitated by a characteristic laryngeal morphology, including a two-layered vocal fold lamina propria, small vocal membrane-like extensions on the free edge of the vocal fold, and a singular ventral laryngeal air pocket known as the ventral pouch. The size and composition of vocal folds (rather than total laryngeal size) appears to contribute to species-specific acoustic properties. Our findings suggest that dual modes of sound production are more widespread among rodents than previously appreciated. Additionally, the common occurrence of NLP highlight the nonlinearity of the vocal apparatus, whereby small changes in anatomy or physiological control trigger large changes in behavioral output. Finally, consistency in mechanisms of sound production used by neonates and adults underscores the importance of considering vocal ontogeny in the diversification of species-specific acoustic signals.

Two pup vocalization types are genetically and functionally separable in deer mice

“…In comparisons of call types within species, we find that cries and USVs are produced with different temporal rhythms, suggesting at least partially distinct neural circuits pattern these behaviors (Zhang and Ghazanfar, 2020). Moreover, cries and USVs most likely arise from physically separate production mechanisms in the larynx, with the low frequency, tonal features of cries being typical of sound produced by laryngeal vocal fold vibration and high frequency sweeps of USVs likely produced by a separate mechanism (Riede et al, 2022). Taking these observations together, distinct Peromyscus call types appear largely unconstrained by one another, which may contribute to their functional specialization in eliciting behavioral responses from parents.…”

Acoustic features of long‐distance calls of wild cheetahs (Acinonyx jubatus) are linked to the caller age from newborns to adults

“…We conclude that vocal ontogeny of cheetahs and other investigated felid species follows a common rule for mammals, that calls of small offspring with their small vocal folds have a higher fundamental frequency than analogous calls of large adults with their large vocal folds (Ey et al, 2007; Fitch & Hauser, 2003; Matrosova et al, 2007), but see exclusions from this rule found in shrew (Schneiderová, 2014; Volodin et al, 2015), rodents (Matrosova et al, 2007, 2011), and artiodactyls (Padilla de la Torre et al, 2015; Volodin et al, 2016). However, in mammals, additionally to calls produced with phonation mechanism based on air flow‐induced vibrations of the vocal folds (Berke & Long, 2010; Herbst, 2014; Herbst et al, 2012) there are calls produced with another mechanism, the aerodynamic whistle, based on airflow vorticities in the vocal tract (Håkansson et al, 2022; Mahrt et al, 2016; Riede et al, 2017, 2022). Calls of the same individual animal produced with phonation mechanism have a substantially lower fundamental frequency than those produced with whistle mechanism (carnivores: Frey et al, 2016; Sibiryakova et al, 2021, artiodactyls: Reby et al, 2016; Volodin, Volodina, & Frey, 2017, rodents: Dymskaya et al, 2022; Fernández‐Vargas et al, 2022).…”

How to analyze and manipulate nonlinear phenomena in voice recordings

“…Sudden changes of f o , known as frequency jumps or pitch jumps, have primarily been researched in the context of human singing [29][30][31], but they are also found in a variety of animal calls [13,32,33] and in human nonverbal vocalizations such as screams [21,34] and baby cries [35]. Their possible causes include both conditions intrinsic to the vocal folds [36,37] and source-filter interaction with the resonances of either the supralaryngeal vocal tract or the tracheal vocal tract [38][39][40][41] ; see Herbst & Elemans in this issue for more details).…”