Biomechanics

Asymmetric toes aid underwater swimming

Abstract

The unique morphology of the toes of the great crested grebe (Podiceps cristatus), which are asymmetrically lobed with a narrower skin flap on the lateral side of the toe, enables these birds to swim very efficiently. Here we study video recordings of a diving grebe and stroboscopic pictures of its moving feet and conclude that the bird uses a hydrodynamically lift-based foot (power) stroke to propel itself underwater, with the separated toes functioning as multiple slots to increase the lift-to-drag ratio. The asymmetric lobes are an adaptation for self-stabilization of the toes during the power stroke, and the toes themselves act as separate hydrofoils, each producing lift and each being twistable individually under hydrodynamic load.

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Figure 1: The great crested grebe's separated toes produce lift.

References

  1. 1

    Webb, P. & Blake, R. W. in Functional Vertebrate Morphology (eds Hildebrand, M., Bramble, D. M., Liem, K. F. & Wake, D. B.) 110–128 (Harvard Univ. Press, Cambridge, MA, 1985).

    Google Scholar 

  2. 2

    Braun, J. & Reif, W.-E. N. Jb. Geol. Paläont. Abh. 169, 307–332 ( 1985).

    Google Scholar 

  3. 3

    Norberg, U. M. Vertebrate Flight (Springer, New York, 1990).

  4. 4

    Hofton, A. New Sci. 146–147 (20 April 1978).

  5. 5

    Norberg, R. Å. Biol. Rev. 48, 561–596 ( 1973).

    Article  Google Scholar 

  6. 6

    Smith, A. M. O. J. Aircraft 12, 501–530 (1975).

    Article  Google Scholar 

  7. 7

    Norberg, R. Å. in The Beginnings of Birds (eds Hecht, M. K., Ostrom, J. H., Viohl, G. & Wellnhofer, P.) (Proc. Int. Archaeopteryx Conf. Eichstätt, 1984, 1985).

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Johansson, L., Lindhe Norberg, U. Asymmetric toes aid underwater swimming. Nature 407, 582–583 (2000). https://doi.org/10.1038/35036689

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