The production of sound in snakes through tail vibration is primarily known among rattlesnakes (Crotalus and Sistrurus). However, despite some species having their acoustic emissions described, many species remain unstudied, such as the South American Rattlesnake Crotalus durissus. In this work, we acoustically characterised the sounds produced by the rattle of the Brazilian Rattlesnake Crotalus durissus cascavella. Additionally, we evaluated the influence of anatomical and physiological attributes of individuals and morphological characteristics of the rattles on the acoustic parameters of the emissions. The rattle sounds produced by C. d. cascavella was not structured in notes, did not show harmonics, nor did it have frequency modulation. The snout-vent length of individuals negatively influenced the minimum and dominant frequencies of emissions. Body temperature positively influenced the minimum frequency. The height of the first lobe of the proximal rattle segment negatively influenced the dominant frequency, while its width negatively influenced both the minimum and dominant frequencies. These observed relationships are consistent with the patterns already reported in other congeners. This characterisation of the rattle sounds produced by C. d. cascavella expands the knowledge about the bioacoustics of the genus Crotalus, contributing to the understanding of the extent of sound emissions in snakes.
Acoustic communication, acoustic signal, defensive behaviour, rattling behaviour, sound production, snakes