Prusten is a form of communicative behaviour exhibited by some members of the family Felidae. Prusten is also referred to as chuffing or chuffle (verb and noun). It is described as a short, low intensity, non-threatening vocalization. In order to vocalize a chuff, the animal's mouth is closed and air is blown through the nostrils, producing a breathy snort. It is typically accompanied by a head bobbing movement. It is often used between two cats as a greeting, during courting, or by a mother comforting her cubs. The vocalization is produced by tigers, jaguars, snow leopards and clouded leopards. Prusten has significance in both the fields of evolution and conservation. Mechanism In tigers, it has been found that low-pitched vocalizations, such as prusten, originate from vibrations of thick vocal folds in the larynx of the cat. Sound production is facilitated by the low threshold pressure required to oscillate the vocal folds, and low glottal resistance. The rough-sounding quality of the low-pitched vocalizations is likely generated by the complex pattern of vocal vibrations, caused by the excitation of multiple modes of oscillation simultaneously. Prusten also involves air being exhaled through the nose at the same time as through the mouth. This may represent an evolutionary shift from exclusively laryngeal vocalizations to mixed nasal and laryngeal sound production in the felid species that display the behaviour. Sound properties Phonetically, prusten varies by species, however the basic structural pattern remains constant. More structural similarities occur between the two leopard species, and also between the tiger and jaguar. Individual sound pulses are more separated in the leopards in comparison to the other species, in which they tend to be more closely merged. Pulses may occur in pairs, in which a basal pulse and an upper-range pulse are produced simultaneously. This may reflect both laryngeal and nasal contributions to the vocalization, with the upper-frequency pulses produced nasally prevailing in tigers and jaguars. The vocalization is produced by repeated, short pulses of air through the nose and mouth, each lasting an average of 0.37 seconds at an average frequency of 248 Hertz in tigers. Frequency compositions are similar throughout the four felid species, however they differ in intensity of low-frequency components. Total numbers of pulses produced per vocalization shows individual variation, but tend to fall in the range of 4-10 for all four species. Studies on tigers have shown that acoustic energy peaks in the low