Swimming kinematics in the axolotl (Ambystmoma mexicanum): do they reflect the same mechanism as in fishes?
D'Août, K.; Aerts, P.; De Vree, F. (1993). Swimming kinematics in the axolotl (Ambystmoma mexicanum): do they reflect the same mechanism as in fishes?, in: Chardon, M. et al. Third Belgian Congress of Zoology, 5-6 November 1993. Belgian Journal of Zoology, 123(Suppl. 1): pp. 13-14 In: Chardon, M.; Goffinet, G. (Ed.) (1993). Third Belgian Congress of Zoology, 5-6 November 1993. Belgian Journal of Zoology, 123(Suppl. 1). University of Liège: Liège. 109 pp., more In: Belgian Journal of Zoology. Koninklijke Belgische Vereniging voor Dierkunde = Société royale zoologique de Belgique: Gent. ISSN 0777-6276; e-ISSN 2295-0451, more |   |
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| Abstract | The kinematics of straight forward swimming at a constant speed was studied in.the neotenic salamander Ambystoma mexicanum by means of high-speed video. Ambystoma mexicanum has an undulatory, anguilliform (eel-like) swimming mode. Important parameters of the propulsive wave (wavelength, frequency, speed and amplitude), and two measures for the mechanical swimming efficiency were calculated: the propeller efficiency (dimensionless) and the specific stride length (body lengths per swimming cycle). Swimming speed was found to be frequency-regulated, while the wavelength of the propulsive wave appeared to be constant. Hence, the speed of the propulsive wave increases with increasing swimming speed. The amplitude of the propulsive wave is minimal just posteriorly to the head and increases considerably to reach a maximum at the tail tip. The mechanical efficiency was found to increase in a hyperbolical manner with increasing swimming speed. Both the propeller efficiency and the specific stride length are thus maximal at high swimming speeds (more than 2.5 body lengths per second), with values of about 0.67 and 0.38 respectively. These characteristics are also typical for anguilliform swimmers among fishes. For the eel (Anguilla anguilla), comparable propulsion wave characteristics have since long been described (1). A propeller efficiency of 0.65 (2) and a stride length of 0.49-0.55 body lengths per second (1, 3) were calculated. Despite the striking analogy in swimming kinematics for the axolotl and the eel, the considerable difference in stride length might reflect a different underlying swimming mechanism. This can be due to a different muscle activation pattern, but to morphological differences as well. For instance, the more homogeneous cross-sectional shape and mass distribution over the eel body when compared to the axolotl, might be related to the observed difference in stride length and reflect a different swimming mechanism. Supported by I.W.O.N.L. grant 920137 (K.D.) and F.K.F.O. grant 2.9005.90 (F.D.V.).(1) I. GRAY (1933). J. Exp. Biol. 10: 88-104.(2) T.L. WILLIAMS (1986). Werner-Gren Int.Symp. Ser. 45: 141-155.(3) 1.1. VIDELER (1993). Fish swimming. Fish and Fisheries Series 10, Chapman &Hall. |
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