The Screamers are a small family of birds, the Anhimidae. For a long time they were thought to be related to the Galliformes because of similar bills, but they are truly related to ducks (family Anatidae), most closely to the Magpie-goose (which some DNA evidence suggests are closer to screamers than to ducks).
The three species occur only in South America, ranging from Venezuela to northern Argentina. They are large, bulky birds, with a small downy head, long legs and large feet which are only partially webbed. They have large spurs on their wings which are used in fights over mates and territorial disputes, these can break off in the breast of other screamers, and are regularly renewed. Unlike ducks they have a partial moult, and are able to fly throughout the year. They live in open areas and marshes with some grass and feed on water plants. One species, the Southern Screamer, is considered a pest as it raids crops and competes with farm birds.
Screamers lay between 2 to 7 white eggs, with four or five being typical. The young, like those of most Anseriformes, can run as soon as they are hatched. The chicks are usually raised in or near water as they can swim better than they can run. This helps them to avoid predators. Like ducks, screamer chicks imprint early in life. This, coupled with their unfussy diet makes them amenable to domestication. They make excellent watchdogs due to their loud screams when encountering anything new and potentially threatening.
It is uncertain whether the three screamer species are endangered or declining. They are seldom hunted, in spite of their conspicuous nature, because their flesh has a spongy texture and is riddled with air-sacs, making it highly unpalatable. The main threats are habitat destruction and increased intensification of agriculture, but the extent of this is unknown.