1 minute read

Rheas: Rheidae

Behavior And Reproduction

Rheas are the largest birds in South America. They are extremely friendly and sociable. In the non-breeding season, the lesser rhea usually live in flocks of five to thirty birds, while the greater rhea live in flocks of ten to one hundred individuals. They are often found grazing alongside herbivorous (plant eating) mammals, such as deer and alpacas. They are fast runners and can reach speeds of up to 37 miles (60 kilometers) per hour, usually running in a zigzag pattern.

Rheas belong to a group of birds called ratites, which are flightless birds that have a flat breastbone rather than a keeled, or curved breastbone like birds of flight. They have a simplified wing bone structure, strong legs, and no feather vanes, making it unnecessary to oil the feathers.

They are polygamous (puh-LIH-guh-mus), meaning they have more than one mate during the breeding season. During breeding season, the male rhea builds a nest in which between two and fifteen females lay their eggs. Nests contain ten to sixty eggs. The male cares for the chicks for about thirty-six hours after they hatch.

During the winter, the flocks split into three groups: single adult males, flocks of two to fifteen females, and yearlings two-years-old and younger. Males challenge each other and try to attract females. This behavior intensifies as the spring and summer breeding season approaches.


Rheas are raised commercially in the United States for their meat. However, although rheas are poultry, their meat is classified as red rather than white. Raw rhea meat is a dark cherry red. After it's cooked, it looks and tastes similar to beef, except it is a little sweeter. Rhea meat is sold as steaks, fillets, medallions (small coin-shaped pieces of meat), roasts, and ground meat. Rhea meat is lower in cholesterol and fat than beef and lower in calories than beef, chicken, and turkey, according to the United States Department of Agriculture (USDA). In 2002, the USDA instituted mandatory inspection of rhea meat in places where the birds are slaughtered.

Additional topics

Animal Life ResourceBirdsRheas: Rheidae - Physical Characteristics, Behavior And Reproduction, Lesser Rhea (pterocnemia Pennata): Species Account - GEOGRAPHIC RANGE, HABITAT, DIET, RHEAS AND PEOPLE, CONSERVATION STATUS