Journal of Ornithology

, Volume 153, Supplement 1, pp 193–198 | Cite as

The legs: a key to bird evolutionary success

  • Anick Abourachid
  • Elizabeth Höfling


Birds are the most diverse and largest group of extant tetrapods. They show marked variability, yet much of this variation is superficial and due to feather and bill color and shape. Under the feathers, the skeleto-muscular system is rather constant throughout the bird group. The adaptation to flight is the explanation for this uniformity. The more obvious morphological adaptations for flight are the wings, but the trunk is always rigid, the tail is short and the neck is flexible, since all these features are correlated with flying behaviour. Unrelated to the exigencies of flight, the legs always have three long bones, and all the birds walk on their toes. This leg structure is a striking plesiomorphic feature that was already present in related dinosaurs. The multi-purpose potential of the legs is the result of the skeletal architecture of a body with three segmented flexed legs. This configuration provides mechanical properties that allow the use of the legs as propulsive, paddling, foraging or grooming tools. It is the association of diverse modes of locomotion—walking, running, hopping, flying and swimming—that have enabled the birds to colonize almost all the environments on Earth.


Locomotion Adaptations Behaviour Hindlimbs Functional morphology 



We are grateful to Pauline Provini and Astrid Willener for providing films and images used for the drawings; to Peter Gibbs (St. Andrews University, Scotland) for linguistic revision of the manuscript; and an anonymous referee for improvements to the text. This contribution was supported by grants from the Unité Mixte de Recherches 7179 Centre national de la recherche scientifique (CNRS) et Muséum National d’Histoire Naturelle, Paris, and Action Transversale Muséum «Formes», France, and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq: Proc. 307542/2006-8) Brazil.


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Copyright information

© Dt. Ornithologen-Gesellschaft e.V. 2012

Authors and Affiliations

  1. 1.Département d’Ecologie et Gestion de la Biodiversité, UMR 7179 CNRSMuséum National d’Histoire Naturelle de ParisParisFrance
  2. 2.Departamento de Zoologia, Instituto de BiociênciasUniversidade de São PauloSão PauloBrazil

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