Rhea (bird)

Rheas Temporal range: Pleistocene-Holocene 0.126–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Two greater rheas
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Infraclass:	Palaeognathae
Order:	Rheiformes
Family:	Rheidae
Genus:	Rhea Brisson, 1760
Type species
Struthio americanus Linnaeus, 1758
Species
†R. anchorenense †R. fossilis †R. mesopotamica †R. subpampeana R. americana American rhea R. pennata Darwin's rhea R. tarapacensis Puna rhea (disputed)
Synonyms
Rhea Moehring 1758 nomen dubium Pterocnemia Gray 1870 Toujou Lacépède 1801 Tujus Rafinesque 1815

Rheas (/ˈriːəz/ REE-əz), also known as ñandus^[a] (/ˈnænduːz/ NYAN-dooz) or South American ostrich,^[1][2] are moderately sized South American ratites (flightless birds without a keel on their sternum bone) of the order Rheiformes. They are distantly related to the African ostriches and Australia's emu (the largest and second-largest living ratites, respectively), with rheas placing just behind the emu in height and overall size.

Most taxonomic authorities recognize two extant species: the greater or American rhea (Rhea americana), and the lesser or Darwin's rhea (Rhea pennata). The International Union for Conservation of Nature (IUCN) classifies the puna rhea as another species instead of a subspecies of the lesser rhea. The IUCN currently rates the greater and puna rheas as near-threatened in their native ranges, while Darwin's rhea is of least concern, having recovered from past threats to its survival. In addition, a feral population of the greater rhea in Germany appears to be growing, though control efforts are underway, and seem to be succeeding in controlling the birds' population growth. Similarly to ostriches and emus, rheas are fairly popular livestock and pets, regularly kept and bred on farms, ranches, private parks and by aviculturists, mainly in North and South America, and Europe.

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