Scaling effects on cervical kinematics in drinking Anatidae
Van der Leeuw, A.H.J. (1992). Scaling effects on cervical kinematics in drinking Anatidae. Neth. J. Zool. 42(1): 23-59
In: Netherlands Journal of Zoology. E.J. Brill: Leiden. ISSN 0028-2960; e-ISSN 1568-542X, more
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| Abstract |
Scaling effects on cervical motion patterns during drinking examined in seven species of Antidae, ranging in body sizefrom small Common Teal to large Mute Swan. Cranio -cervical anantomy, head and body movements and representative cervical motion patterns were compared for the immersion, upstroke and tip up phases. Cranio-cervical anatomy is characterized by 5 functionally different regions in the neck (functional components) and it is modified by shorter vertebrae in smaller species while in larger species the number of vertebrae is increased, especially in the second functional component. A 'General Anatid' motion pattern was found in Mallard and White-fronted Goose, two intermediate sized species. The pattern comprises three synchronous waves of rotations runnig from caudal to rostral through three functional components, each starting from a different joint. Scalling effects were found in species smaller than the Mallard and in the much larger Swan. Modifications in Teal, Shoveler and Wigeon comprise extra rotations in the caudal part of the neck, since rotations of the relatively short vertebrae do not result in a sufficient head elevation and compensation. In Swans, the rostral wave of rotations of the "General Anatid" pattern is replaced by a "Bike Chain" pattern in which a wave of rotations to dorsal followed by rotations to ventral runs from rostral to caudal. This results in minimization of: 1) the large forces per joint which develop due to the relatively long rostral cervical region and 2) the amount of water expelled by gravity and centrifugal forces. Other factors influence the cervical motion patterns as well. The Tufted Duck shows a "Bike Chain" pattern along the whole cervical column, which can be explained es a trophic effect: the drinking mechanism is different, due to a modified mouth is an adaptation to the major type of food intake, so that different functional demands are put on the cervical motion pattern. |
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