The Muscovy duck (Cairina moschata) is a large duck native to Mexico, Central, and South America. They are large ducks, with the males about 76 cm (30 in) long, and weighing up to 7 kg (15 lb). Females are considerably smaller, and only grow to 3 kg (6.6 lb), roughly half the males’ size. The bird is predominantly black and white, with the back feathers being iridescent and glossy in males, while the females are more drab. The amount of white on the neck and head is variable, as well as the bill, which can be yellow, pink, black, or any mixture of these. The Muscovy duck’s diet consists of plant material obtained by grazing or dabbling in shallow water, and small fish, amphibians, reptiles, crustaceans, insects, and millipedes. This is a somewhat aggressive duck; males often fight over food, territory or mates. The females fight with each other less often. Some adults will peck at the ducklings if they are eating at the same food source.