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Anatomy and histochemistry of spread‐wing posture in birds. 4. Eagles soar with fast, not slow muscle fibres
Author(s) -
Meyers Ron A.,
McFarland Joshua C.
Publication year - 2016
Publication title -
acta zoologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.414
H-Index - 37
eISSN - 1463-6395
pISSN - 0001-7272
DOI - 10.1111/azo.12125
Subject(s) - anatomy , biology , isometric exercise , wing , physiology , physics , thermodynamics
Slow fibres are typically characterized as functioning in avian postural behaviours such as soaring flight and are described for a number of elite soarers such as vultures, pelicans and albatrosses. Golden Eagles and Bald Eagles also display soaring behaviour, and we examined their flight muscles for the presence of slow fibres. Surprisingly, eagles lack a deep layer to the pectoralis found in other soaring species. Additionally, the pectoralis as well as other shoulder muscles had few to no slow muscle fibres. The lack of functionally meaningful numbers of slow muscle fibres in eagle flight muscles indicates that they must rely on fast fibres for posture; these can function in that role due to their high aerobic capacity and also perhaps a ‘tuning’ of muscle contraction frequency to function more efficiently at isometric contractions.