AskDefine | Define flightless

Dictionary Definition

flightless adj : incapable of flying

User Contributed Dictionary



  • AHD: flīt'lĭs


  1. Unable to fly. Usually used with birds such as the penguin, ostrich, and emu.


unable to flight

Extensive Definition

Flightless birds are birds which have lost 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. 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 is likely not the case for the ratites; the ostrich, emu and cassowary, as all have claws on their feet to use as a weapon against predators.
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.
Some flightless varieties of island birds are closely related to flying varieties, implying flight is a significant biological cost.
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) (although some extinct species grew to larger sizes).
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.

List of recent flightless birds

The following are flightless birds during or after the Holocene period.


Podicipediformes (Grebes)

Pelicaniformes (Pelicans, Cormorants, et al)

Sphenisciformes (Penguins)

Coraciiformes (Kingfishers, Hornbills, et al)

Ciconiiformes (Herons, Ibis)

Charadriiformes (Gulls, Terns, Auks)

Psitticiformes (Parrots)

Columbiformes (Pigeons, Doves)

Caprimulgiformes (Nightjars)

Passeriformes (Perching Birds)


  • Rails: A Guide to the Rails, Crakes, Gallinules and Coots of the World
flightless in Bosnian: Ptice neletačice
flightless in German: Flugunfähiger Vogel
flightless in Korean: 날지 못하는 새
flightless in Polish: Nielot
flightless in Russian: Нелетающие птицы
flightless in Serbian: Тркачице
flightless in Tamil: பறக்காத பறவைகள்
Privacy Policy, About Us, Terms and Conditions, Contact Us
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2
Material from Wikipedia, Wiktionary, Dict
Valid HTML 4.01 Strict, Valid CSS Level 2.1