From screams to whistles: audible and ultrasonic vocal repertoire from an endangered rodent species, the goytaca-rat Cerradomys goytaca

Here we describe the vocal repertoire of goytaca-rat, Cerradomys goytaca, an endangered Neotropical species, and present the first record of ultrasonic vocalisations for the Sigmodontinae subfamily. We recorded captive individuals housed at the Universidade Federal do Rio de Janeiro, Brazil. We tested several stimuli to elicit vocalisations, and the best configuration was when individuals were in pairs. Thus, recordings were separated into homo- and heterosexual dyads of related and unrelated individuals, as well as one mother and her offspring. We identified six vocal types, spanning a wide frequency spectrum from audible to ultrasonic ranges. Mathematical classification identified three to four vocal types, with some classes, such as ‘quaver’ and ‘sweep calls’, showing high classification accuracy, while others, such as ‘squeak’, exhibiting low accuracy. Hierarchical clustering analysis revealed significant overlap between certain vocalisation classes, suggesting the possibility of a continuum vocal repertoire in the species. We also identified that the emission of different vocalisation types varied across pairing settings, such as quavers, which was the most frequent in unrelated male-female pairing recordings. The vocal repertoire of this species is surprisingly rich and may give future insights into their socio-ecology requirements.