What is Rhea (bird)?
{{Taxobox | name = ''Rhea'' | image = greater rhea pair arp.jpg | image_width = 250px | image_caption = [[American rhea]], ''Rhea americana'' | regnum = [[Animal]]ia | phylum = [[Chordate|Chordata]] | classis = [[bird|Aves]] | ordo = [[Rheiformes]] | familia = '''Rheidae''' | genus = '''''Rhea''''' | subdivision_ranks = [[Species]] | subdivision = * ''Rhea americana'' * ''Rhea pennata'' (Darwin's rhea) }} The '''rheas''' are [[flightless birds]] of the genus ''Rhea'', native to [[South America]]. They are [[ratites]], which means they are large flightless birds with no keel to their breastbone or [[sternum]]. == Description == The greater or American rhea (also called the 'Nandu') is a large, flightless bird from forests of South America. This [[ratite]] is the largest bird in the Americas. It is a fast runner; and when it runs, its neck is almost horizontal to the ground. Rheas congregate in flocks of 20 to 30 birds. The lesser or Darwin's rhea, ''Rhea pennata'', is mostly found in the southern part of South America. == Diet == Rheas eat mostly plants, fruits, seeds, and nuts, but also will also eat insects and other small animals (like [[lizard]]s).<ref>Davies S.J.J.F. 2003. Rheas. In Hutchins, Michael (ed). ''Grzimek's Animal Life Encyclopedia'', volume 8: Birds I Tinamous and Ratites to Hoatzins. 2nd ed, Farmington Hills, MI: Gale Group. pp. 69–71. {{ISBN|0787657840}}</ref> == Reproduction == The female rhea lays 12-30 yellow-cream eggs in a clutch. The male digs the nest (a simple scrape in the ground), incubates the eggs (for 6 weeks), and raises the chicks. Rheas are mature at 2 years of age. == Evolution == It was once thought that ratites were all one [[monophyletic]] group, which evolved together in Gondwana in the [[Upper Cretaceous]]. Then they evolved in their separate ways as Gondwana split up, and the parts drifted apart. The parts became the modern southern continents, plus [[Africa]] and the [[Indian subcontinent]]. However, modern [[sequence analysis|genetic analysis]] conflicts with this.