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J Exp Biol. 2015 Dec;218(Pt 23):3836-44. doi: 10.1242/jeb.126193.

Guineafowl with a twist: asymmetric limb control in steady bipedal locomotion.

Author information

1
Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA rkambic@fas.harvard.edu.
2
Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA.

Abstract

In avian bipeds performing steady locomotion, right and left limbs are typically assumed to act out of phase, but with little kinematic disparity. However, outwardly appearing steadiness may harbor previously unrecognized asymmetries. Here, we present marker-based XROMM data showing that guineafowl on a treadmill routinely yaw away from their direction of travel using asymmetrical limb kinematics. Variation is most strongly reflected at the hip joints, where patterns of femoral long-axis rotation closely correlate to degree of yaw divergence. As yaw deviations increase, hip long-axis rotation angles undergo larger excursions and shift from biphasic to monophasic patterns. At large yaw angles, the alternately striding limbs exhibit synchronous external and internal femoral rotations of substantial magnitude. Hip coordination patterns resembling those used during sidestep maneuvers allow birds to asymmetrically modulate their mediolateral limb trajectories and thereby advance using a range of body orientations.

KEYWORDS:

Animation; Avian; Bipedalism; Kinematics; Locomotion; Numida meleagris; Three-dimensional; X-ray; XROMM

PMID:
26632457
DOI:
10.1242/jeb.126193
[Indexed for MEDLINE]
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