The
rheas are species of ratites (
flightless birdFlightless birds are birds which lack the ability to fly, relying instead on their ability to run or swim, and are thought to have evolved from their flying ancestors. There are about forty species in existence today, the best known being the ostrich, emu, cassowary, rhea, kiwi, and penguins...
s, with unkeeled sterna) in the genus
Rhea, native to
South AmericaSouth America is the southern continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere...
. There are two existing species: the Greater or American Rhea and the
Lesser or Darwin's RheaDarwin'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.-Description:...
. The genus name was given in 1752 by
Paul MohringPaul Heinrich Gerhard Möhring AKA Paul Mohr was a German physician, botanist and zoologist.Möhring was physician to the Prince of Anhalt. In 1752 he published Avium Genera, an early attempt to classify bird species, which divided birds into four classes and shows the beginnings of the modern...
and adopted as the English common name. Mohring's reason for choosing this name, from the
RheaThis page is about the Greek mythological figure. For the bird, see Rhea .Rhea was the Titaness daughter of Ouranos, the sky, and Gaia, the earth, in classical Greek mythology...
of classical mythology, is not known.
Rheas are large, flightless birds with gray-brown plumage, long legs and long necks, similar to an
ostrichThe ostrich, Struthio camelus, is a large flightless bird native to Africa. It is the only living species of its family, Struthionidae and its genus, Struthio. Ostriches share the order Struthioniformes with the kiwis, and other ratites...
.
The
rheas are species of ratites (
flightless birdFlightless birds are birds which lack the ability to fly, relying instead on their ability to run or swim, and are thought to have evolved from their flying ancestors. There are about forty species in existence today, the best known being the ostrich, emu, cassowary, rhea, kiwi, and penguins...
s, with unkeeled sterna) in the genus
Rhea, native to
South AmericaSouth America is the southern continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere...
. There are two existing species: the Greater or American Rhea and the
Lesser or Darwin's RheaDarwin'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.-Description:...
. The genus name was given in 1752 by
Paul MohringPaul Heinrich Gerhard Möhring AKA Paul Mohr was a German physician, botanist and zoologist.Möhring was physician to the Prince of Anhalt. In 1752 he published Avium Genera, an early attempt to classify bird species, which divided birds into four classes and shows the beginnings of the modern...
and adopted as the English common name. Mohring's reason for choosing this name, from the
RheaThis page is about the Greek mythological figure. For the bird, see Rhea .Rhea was the Titaness daughter of Ouranos, the sky, and Gaia, the earth, in classical Greek mythology...
of classical mythology, is not known.
Description
Rheas are large, flightless birds with gray-brown plumage, long legs and long necks, similar to an
ostrichThe ostrich, Struthio camelus, is a large flightless bird native to Africa. It is the only living species of its family, Struthionidae and its genus, Struthio. Ostriches share the order Struthioniformes with the kiwis, and other ratites...
. These birds can reach , and weigh up to . Their wings are large for a flightless bird and are spread while running, to act like sails. Unlike most birds, rheas have only three toes. Their
tarsusIn tetrapods, the tarsus are the cluster of bones in the foot between the tibia and fibula and the metatarsus. The bones of the tarsus do not belong to individual toes, whereas those of the metatarsus do...
has horizontal plates on the front of it. They also store urine separately in an expansion of the
cloacaIn zoological anatomy, a cloaca is the posterior opening that serves as the only such opening for the intestinal, reproductive and urinary tracts of certain animal species. The word comes from Latin, and means sewer...
.
Taxonomy
The recognized extant species are:
- Greater Rhea Rhea americana
- R. a. americana, found in campos
Campos is a popular surname in Portuguese speaking countries including Brazil. It may refer to different things:-Portugal:*Campos , parish in Póvoa de Lanhoso...
of northern and eastern BrazilBrazil , officially the Federative Republic of Brazil , is a country in South America. It is the fifth largest country by geographical area, occupying nearly half of South America, the fifth most populous country, and the fourth most populous democracy in the world. Bounded by the Atlantic Ocean...
.
- R. a. intermedia, southeastern Brazil
Brazil , officially the Federative Republic of Brazil , is a country in South America. It is the fifth largest country by geographical area, occupying nearly half of South America, the fifth most populous country, and the fourth most populous democracy in the world. Bounded by the Atlantic Ocean...
in Rio Grande do SulRio Grande do Sul is the southernmost State of Brazil, and the State with the fourth highest Human Development Index in the country. In Rio Grande do Sul we can find the most southern city of the country, Chuí, on the border with Uruguay...
and UruguayUruguay , is a country located in the southeastern part of South America. It is home to 3.46 million people, of whom 1.1 million live in the capital Montevideo and its metropolitan area. An estimated 88–94% of the population are of mostly European and/or mixed descent.Uruguay's only land border is...
.
- R. a. nobilis, eastern Paraguay
Paraguay, officially the Republic of Paraguay , is one of the two landlocked countries which lie entirely within the Western Hemisphere, the other being Bolivia, both in South America....
, east of Rio Paraguay.
- R. a. araneipes, chaco of Paraguay to Bolivia
Bolivia, officially Plurinational State of Bolivia , is a landlocked country in central South America. It is bordered by Brazil to the north and east, Paraguay and Argentina to the south, and Chile and Peru to the west....
and Mato GrossoMato Grosso is one of the states of Brazil, the third largest in area, located in the western part of the country....
in Brazil.
- R. a. albescens, plains of Argentina
Argentina, officially the Argentine Republic , is the second largest country in South America, constituted as a federation of 23 provinces and an autonomous city, Buenos Aires. It is the eighth largest country in the world by land area and the largest among Spanish-speaking nations, though Mexico,...
south to Rio NegroRío Negro is a province of Argentina, located at the northern edge of Patagonia. Neighboring provinces are from the south clockwise Chubut, Neuquén, Mendoza, La Pampa and Buenos Aires. To the east lies the Atlantic Ocean.Its capital is Viedma...
.
- Lesser Rhea Rhea pennata
- R. p. garleppi, puna
Puna is a type of montane grassland found in the central Andes Mountains of South America. It is considered one of the eight Natural Regions in Peru, but extends south as far as northern Argentina and Chile.-Setting:...
of southeastern PeruPeru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean.Peruvian territory was home to the Norte Chico...
, southwestern Bolivia, and northwestern Argentina.
- R. p. tarapacensis, northern Chile
Chile, officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...
from Atacama to TarapacáTarapacá may refer to:*Tarapacá Region, Chile*Tarapacá Department *Tarapacá Province...
.
- R. p. pennata, Patagonian steppes in southern Argentina and southern Chile.
Rhea pennata was not always in the
Rhea genus. In 2008 the
SACCThe American Ornithologists' Union is an ornithological organization in the USA. Unlike the National Audubon Society, its members are primarily professional ornithologists rather than amateur birders...
, the last holdout, approved the merging of the genera,
Rhea and
Pterocnemia on August 7, 2008. This merging of genera leaves only the
Rhea genus. A third species of rhea,
Rhea nana, was described by
LydekkerRichard Lydekker was an English naturalist, geologist and writer of numerous books on natural history.Lydekker was born in London, and educated at Trinity College, Cambridge, where he took a first-class in the Natural Science tripos...
in 1894 based on a single egg found in
PatagoniaPatagonia is a geographic region containing the southernmost portion of South America. Located in Argentina and Chile, it comprises the southernmost portion of the Andes mountains to the west and south, and plateaux and low plains to the east. The name Patagonia comes from the word patagón used by...
, but today no major authorities consider it valid.
Individual and flocking
Rheas tend to be silent birds with the exception being when they are chicks or when the male is seeking a mate. During the non-breeding season they may form flocks of between 10 and 100 birds, although the lesser rhea forms smaller flocks than this. When in danger they flee in a zigzag course, utilizing first one wing then the other, similar to a rudder. During breeding season the flocks break up.
Diet
They are
omnivorousOmnivores are species that eat both plants and animals as their primary food source...
, preferring broad-leafed plants, but also eating seeds, roots, fruit, lizards, beetles, grasshoppers, and carrion.
Reproduction
Rheas are polygamous, with males courting between two and twelve females. After mating, the male builds a nest, in which each female lays her eggs in turn. The nest consists of a simple scrape in the ground, lined with grass and leaves. The male incubates from ten to sixty eggs. The male will utilize a decoy system and place some eggs outside the nest and sacrifice these to predators, so that they won't attempt to get inside the nest. The male may utilize another subordinate male to incubate his eggs, while he finds another harem to start a second nest. The chicks hatch within 36 hours of each other. The females, meanwhile, may move on and mate with other males. While caring for the young, the males will charge at any perceived threat that approach the chicks including female rheas and humans. The young reach full adult size in about six months but do not breed until they reach two years of age..
Human interaction
Rheas have many uses in South America. Feathers are used for feather dusters, skins are used for cloaks or leather, and their meat is a staple to many people.
External links