The monotypic Torrent Duck is an Andean endemic and a specialist of cold fast-flowing mountain streams, a raucous and fairly unproductive environment to which only three other species of duck in the world that have been able to adapt. The Torrent Duck is highly sexually dimorphic. In contrast to most other ducks, the female is just as colorful as the male, but with an entirely different color scheme. Further, males show considerable geographic variation in head patterning and extend of black in the underparts whereas the female’s plumage remains the same throughout the range. Virtually sedentary, the Torrent Duck remains close to its mate throughout its reproductive life, but young birds will range widely before establishing a territory.