Sound production by the river bullhead, Cottus gobio (L). (Cottidae, Teleostei)

Cottus gobio is solitary, maintains territories, and defends them by threat display, seldom by biting and fighting. Threatening consists of spreading gill covers and fins, darkening, and sound production. Calling is accompanied by a nodding movement of the head, during which the pectoral girdle and the skull are moved rapidly against each other. Males emitted significantly more sounds than females. An increase in the number of encounters and calls was noted when temperatures were raised from 8°C to 13°C. -from Author