Structure, function, and mechanism of Rodentia vocalizations across the lifespan.

Vocalizations are an integral way that rodents and many other mammals communicate. Historically, research on rodent vocalizations focused on laboratory-derived strains of two species, house mice (Mus musculus), and brown rats (Rattus norvegicus). However, with over 2,000 species, Rodentia is one of the largest vertebrate orders with many other species available for communication research. In this review, we synthesize recent findings on lesser-studied species spanning five Rodentia families: Muridae, Caviidae, Cricetidae, Bathyergidae (includes Heterocephalidae), and Sciuridae. First, we take an evolutionary perspective to compare adult vocalizations within and across these five Rodentia families. Then, we take a developmental perspective to characterize immature vocalizations and how they transition to mature vocalizations. Next, we survey the potential functions of rodent by examining the behavioural contexts in which they occur. Finally, we summarize findings on the physiological mechanisms that underpin rodent vocalizations, from biomechanics to neuromodulator systems and neural circuits. Together, this research shows that Rodentia is an excellent taxonomic group for exploring the diversity and evolution of vertebrate acoustic communication.