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By Maija K. Schommer
Geographic Range
The common rhea lives in south-eastern part of South America.
Biogeographic Regions:
neotropical 
(native ).
Habitat
Rheas live in pampas, campos, cerrado and open chaco woodland of South America. They avoid open grassland. Rheas live in areas with at least some tall vegatation. During the breeding season, they stay near rivers, lakes, or marshes.
Terrestrial Biomes:
desert or dune ; savanna or grassland ; chaparral ; scrub forest .
Physical Description
(50.6 lbs)
Largest South American bird, flightless, unmistakeable due to its great height, massive legs, and terrestrial habits.
Some key physical features:
endothermic ; bilateral symmetry .
Reproduction
Their breeding season is from August to January, depending on the region. Males court two to twelve females. Once mating has occurred, the males build nests, which are shallow holes in the ground with a rim that is surrounded by twigs and vegatation. Each of the females lay one egg in the male's nest every other day for a period of seven to ten days. After the first two or three days of egg laying, the male stays with his nest and eggs and begins incubating them. A male usually incubates ten to sixty eggs. The chicks hatch within thirty-six hours of each other. The male takes care of the chicks by himself. Female rheas move from male to male throughout the breeding season.
Key reproductive features:
iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous .
Behavior
During the spring, male rheas are solitary, and females form into small groups. Yearlings form a flock until they are two years old, which is when they are ready to breed. At the end of the summer males, females, and chicks come together to form large flocks for the winter months. The flocks formed after the breeding season contain twenty to thirty and sometimes as many as one hundred rheas.
Key behaviors:
motile .
Food Habits
Rheas are omnivorous, preferring broad-leaved plants and clover. However, they eat a variety of seeds, roots and fruits. They also eat insects, including grasshoppers; small vertebrates, such as lizards, frogs, small birds and snakes. Rheas continuously move as they feed.
Economic Importance for Humans: Negative
Rheas are a pest to farmers because they will eat almost any agricultural crop.
Economic Importance for Humans: Positive
Rhea feathers are used to make feather dusters in South America. Their skins are used for leather, their meat and eggs are consumed by man and dogs.
Conservation Status
The rhea population has declined considerably and is considered to be near threatened. In 1980, over 50,000 skins were traded; however a permit is now needed for their export and import. Rheas and their eggs are eaten by local people. They are also killed to be used as dog food. Rhea chicks are threatened by many predators. The rhea's habitat has become limited due to agricultural progress. Rheas are eliminated near agricultural areas, because they will eat almost any crop.
Other Comments
Rheas cannot fly. However, they have unusually long wings for flightless birds. They use their wings like an airplane rudder, in order to help them dodge predators. When male rheas are taking care of their young, they will charge at female rheas and humans who come to close to the chicks. Cowboys working near rheas take dogs with them to divert or discourage the male's charge.
Contributors
Maija K. Schommer (author), University of Michigan.
