All species of catfishes can generate sound through stridulation, and many produce sounds through . Stridulation consists of the clicking or grinding of bony parts on the fish's pectoral fins and pectoral girdle, and drumming consists of the contraction of specialized sonic muscles with subsequent reverberation through the swim bladder. Variability in the sound signals created by the channel catfish depends on the mechanism by which the sound is produced, the function of the resultant sound, and physical factors such as sex, age, and temperature. This variation may result in increased complexity of the outgoing signal and may allow for increased usefulness of the signal in interspecies communication. In the channel catfish, sounds are produced only by pectoral stridulation, as this species does not express sonic muscles. However, the swim bladder may still be used to help with audition.