The Darwin's rhea (Rhea pennata), also known as the lesser rhea, is a large flightless bird, but the smaller of the two extant species of rheas. It is found in the Altiplano and Patagonia in South America.
The lesser rhea stands at 90 to 100 cm (35–39 in) tall. Length is 92 to 100 cm (36–39 in) and weight is 15 to 28.6 kg (33–63 lb).Like most ratites, it has a small head and a small bill, the latter measuring 6.2 to 9.2 cm (2.4 to 3.6 in), but has long legs and a long neck. It has relatively larger wings than other ratites, enabling it to run particularly well. It can reach speeds of 60 km/h (37 mph), enabling it to outrun predators. The sharp claws on the toes are effective weapons. Their feathers are similar to those of ostriches, in that they have no aftershaft. Their plumage is spotted brown and white, and the upper part of their tarsus is feathered.The tarsus is 28 to 32 cm (11 to 13 in) long and has 18 horizontal plates on the front.