A Rhea is a large South American flightless bird similar to an emu or ostrich.
Darwin’s Rhea is smaller, with denser feathers than the Grey, or Common Rhea due to its choice of a much harsher and colder habitat.
There are two sub-species of Darwin’s Rhea that live in South America. One favouring the high plains of the Andes (Chile north through Bolivia into Peru), and the other favouring the semi-desert grass and scrublands of Patagonia in Argentina. They have been long time natives of the region with fossilized Rheas dating back nearly two million years being found in parts of Argentina.
Because Rheas eat the same foods as sheep, they have long been considered competitors for precious grazing. However, it would appear that they eat most of the burr-like seeds that would otherwise foul the fleece of the sheep. They are increasingly being considered useful. Metabolism of these seeds, plus the juiciness of the plants, allow Rheas to live in areas with little water.