One of the world's more distinctive and widespread tropical ducks, the Comb Duck occurs throughout much of the world's tropical lowlands. In South America, the Comb Duck is widespread throughout slow-moving fresh water in the lowlands north of the Southern Cone. It occurs in every mainland country except Suriname and Chile, but is restricted in Argentina to the northeast, is a vagrant to French Guiana and Trinidad, and occurs locally in eastern Panama. The Comb Duck is large and very distinctive, and is unmistakable within the Neotropics. It can often be seen flying over water, and is eye-catching and distinctive, with its broad wings and striking black-and-white plumage, especially when seen against a background of green vegetation. Comb Ducks can also often be seen grazing on small fish and invertebrates by swimming slowly and dabbling on the surface. Comb Ducks are sexually dimorphic: the male is larger than the female and has a large, black, oblong crest above the bill. The Comb Duck is the only member of its genus.