Darwin's rhea or the lesser rhea (Rhea pennata) is a large flightless bird, the smaller of the two extant species of rheas. It is found in the Altiplano and Patagonia in South America. Description The lesser rhea stands at tall. Length is and weight is . Like most ratites, it has a small head and a small bill, the latter measuring , 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 long and has 18 horizontal plates on the front. Etymology It is known as ñandú petiso, or ñandú del norte, in Argentina, where the majority live. Other names are suri and choique. The name ñandú comes from the greater rhea's name in Guaraní, ñandu guazu, meaning big spider, possibly in relation to their habit of alternately opening and lowering their wings when they run. In English, Darwin's rhea gets its scientific name from Rhea, a Greek goddess, and pennata, meaning winged. The specific name was bestowed in 1834 by Darwin's contemporary and rival Alcide d'Orbigny, who first described the bird to Europeans from a specimen from the lower Río Negro south of Buenos Aires, Argentina. As late as 2008, it was classified in the monotypic genus Pterocnemia. This word is formed from two Greek words pteron, meaning feathers, and knēmē, meaning the leg between the knee and the ankle, hence feather-legged, alluding to their feathers that cover the top part of the leg. In 2008, the SACC subsumed Pterocnemia into the genus Rhea. Taxonomy Three subspecies have traditionally been recognized: R. p. garleppi is found in the puna of southeastern Peru, southwestern Bolivia, and northwestern Argentina. R. p. pennata is found in the Patagonian steppes of Argentina and Chile. The IUCN considers the former two northern taxa R. p. tarapacensis and R. p. garleppi as a separate species, the puna rhea (R. tarapacensis). Both garleppi and tarapacensis were described by Charles Chubb in 1913. It is possible garleppi should be considered a junior synonym of tarapacensis. Behavior The lesser rhea