Hissing and spitting (the more intense variation) are involuntary reactions to when a cat is surprised by an (apparent) enemy. The cat changes position with a startle and breath is being forced rapidly through the slightly open mouth before stopping suddenly; [fft], [ɧ] or [ç]. Hissing and spitting are agonistic (aggressive and defensive) sounds produced with the mouth wide open and the teeth exposed. They sound a bit like a long exhalations. The spit sounds similar to a hiss, but sometimes can begin with a t-like sound, e.g. [tʃ].

The image to the right shows the phonetic characteristics (waveform, spectrogram and pitch contour) and gives an audio example of a domestic cat hiss.