Flightless birds evolved from flying ancestors; there are about forty species in existence today. The best-known flightless birds are the ostrich, emu, cassowary, rhea and penguins. It is believed by some that most flightless birds evolved in the absence of predators, on islands, and lost the power of flight because they had few enemies--although this likely not the case for the ratites; the ostrich, emu and cassowary, as all have claws on their feet/birds to use as a weapon against predators. Binomial name Struthio camelus Linnaeus, 1758 The present-day distribution of ostriches. ... Binomial name Dromaius novaehollandiae (Latham, 1790) The Emu has been recorded in the areas shown in black. ... Species Casuarius casuarius Casuarius unappendiculatus Casuarius bennetti Cassowaries (genus Casuarius) are very large flightless birds native to the tropical forests of New Guinea and northeastern Australia. ... Species R. americana R. pennata The Rhea, also known as ñandú (pronounced ) in Spanish, or ema in Portuguese, is a large flightless ratite bird native to South America. ... Modern genera Aptenodytes Eudyptes Eudyptula Megadyptes Pygoscelis Spheniscus For prehistoric genera, see Systematics Some penguins are curious. ... For other meanings of bird, see bird (disambiguation). ... Families Struthionidae Casuariidae Dinornithidae Apterygidae Rheidae A ratite is any of a diverse group of large, flightless birds of Gondwanian origin, most of them now extinct. ... Binomial name Struthio camelus Linnaeus, 1758 The present-day distribution of ostriches. ... Binomial name Dromaius novaehollandiae (Latham, 1790) The Emu has been recorded in the areas shown in black. ... Species Casuarius casuarius Casuarius unappendiculatus Casuarius bennetti Cassowaries (genus Casuarius) are very large flightless birds native to the tropical forests of New Guinea and northeastern Australia. ...

Two key differences between flying and flightless birds are the smaller wing bones of flightless birds and the absent (or greatly reduced) keel on their breastbone. The keel anchors muscles needed for wing movement[1]. Flightless birds also have more feathers than flying birds.

New Zealand has more species of flightless birds (including the kiwis, several species of penguins, and the takahe) than any other country. One reason is that until the arrival of humans roughly 1000 years ago, there were no large land predators in New Zealand; the main predators of flightless birds were larger birds[2]. Species See text. ... Modern genera Aptenodytes Eudyptes Eudyptula Megadyptes Pygoscelis Spheniscus For prehistoric genera, see Systematics Some penguins are curious. ... Binomial name Porphyrio mantelli Owen, 1848 The Takahē, Porphyrio mantelli is a flightless bird native to New Zealand which belongs to the rail family. ...

Some flightless varieties of island birds are closely related to flying varieties, implying flight is a significant biological cost.

With the introduction of mammals (among them humans) to the habitats of flightless birds, many have become extinct, including the Great Auk, the Dodo, and the Moa. Binomial name Pinguinus impennis (Linnaeus, 1758) The Great Auk (Pinguinus impennis) is an extinct bird. ... Binomial name Raphus cucullatus Linnaeus, 1758 Former range (in red) Synonyms Didus ineptus The Mauritius Dodo (Raphus cucullatus), more commonly just dodo, was a metre-high (three-foot) flightless bird related to the pigeons that lived on the islands of Mauritius. ... Genera Anomalopteryx (bush moa) Euryapteryx Megalapteryx (upland moa) Dinornis (giant moa) Emeus Pachyornis Moa were giant flightless birds native to New Zealand. ...

The smallest flightless bird is the Inaccessible Island Rail (length 12.5 cm, weight 34.7 g). The largest (both heaviest and tallest) flightless bird, which is also the largest living bird, is the Ostrich (2.7 m, 156 kg)[3] (although the largest moas where up to 13 feet tall and could have weighed around 400kg). Binomial name Atlantisia rogersi Lowe, 1923 The Inaccessible Island Rail, Atlantisia rogersi, is a small bird of the rail family, Rallidae. ... Genera Anomalopteryx (bush moa) Euryapteryx Megalapteryx (upland moa) Dinornis (giant moa) Emeus Pachyornis Moa were giant flightless birds native to New Zealand. ...

Flightless birds are the easiest to take care of in captivity because they do not have to be caged. Ostriches were once farmed for their decorative feathers. Today they are raised for meat and for their skins, which are used to make leather.

There were also other families of flightless birds, such as the now extinct Phorusrhacidae, that evolved to be very powerful terrestrial predators. Synonyms Phororhacosidae Ameghino, 1889 Phororhacidae Lydekker, 1893 Brontornithidae Moreno & Mercerat, 1891 Darwinornithidae Moreno & Mercerat, 1891 Stereornithidae Moreno & Mercerat, 1891 Patagornithidae Mercerat, 1897 Devincenziidae Kraglievich, 1932 Mesembriorniidae Kraglievich, 1932 Phorusrhacidae Brodkorb, 1963 Phorusrhacoids, or Terror Birds, were large carnivorous flightless birds that were the dominant predators in South America during the...

==See also==

• Extinct birds
• Ratite
• Phorusrhacidae
• Dinosaur-bird connection: Are some dinosaurs secondarily flightless ?

'Italic text'Italic text'Italic text'Italic text'Italic text'Italic text'Italic text'Italic text'Italic text'Italic text'Italic text'Italic text''''''''''''''''''' Since 1500, over 100 species of birds have become extinct, and this rate of extinction seems to be increasing. ... Families Struthionidae (ostriches) Rheidae (rheas) Casuariidae (emus etc. ... Synonyms Phororhacosidae Ameghino, 1889 Phororhacidae Lydekker, 1893 Brontornithidae Moreno & Mercerat, 1891 Darwinornithidae Moreno & Mercerat, 1891 Stereornithidae Moreno & Mercerat, 1891 Patagornithidae Mercerat, 1897 Devincenziidae Kraglievich, 1932 Mesembriorniidae Kraglievich, 1932 Phorusrhacidae Brodkorb, 1963 Phorusrhacoids, or Terror Birds, were large carnivorous flightless birds that were the dominant predators in South America during the... The current scientific consensus holds that birds evolved from theropod dinosaurs. ...

Reference

Taylor, Barry (1998). Rails: A Guide to the Rails, Crakes, Gallinules and Coots of the World. Yale University Press. ISBN 0-300-07758-0. 

External links

• TerraNature pages on New Zealand flightless birds