Screamers are a unique group of three bird species found in South America, ranging from Colombia to northern Argentina. These species, which include the horned screamer (Anhima cornuta), the southern screamer or crested screamer (Chauna torquata), and the northern screamer or black-necked screamer (Chauna chavaria), were once thought to be similar to Galliformes due to their bill structure but are actually closer to ducks and specifically the magpie goose. Their skeletal structure is distinct among birds as they lack the uncinate processes of ribs. Screamers have sparse fossil records but are thought to have a potential Eocene ancestor and are historically related to the presbyornithids from which they may have evolved, changing from a filter-feeding to an herbivorous diet. These large, bulky birds with a small head and long legs inhabit marshes with some grass and are known for their spurs used in territorial and mating disputes, their ability to fly year-round, and their diet on water plants. While the southern and horned screamers are fairly common and not considered threatened, the northern screamer is rarer and near threatened. Screamers are not popular for hunting due to the unpleasant texture of their meat, facing habitat destruction and agriculture as their primary threats. They are also known for laying 2-7 white eggs and possessing a high capacity for domestication attributing to their adaptable diet and tendency to imprint on humans, which also makes them suitable as guard animals.