How seabirds (Morus bassanus and Sula leucogaster) plunge-dive without injuries


Meeting Abstract

123-7  Sunday, Jan. 8 11:30 – 11:45  How seabirds (Morus bassanus and Sula leucogaster) plunge-dive without injuries JUNG, S*; CHANG, B; CROSON, M; STRAKER, L; GART, S; DOVE, C; GERWIN, J; Virginia Tech; Virginia Tech; Virginia Tech; Smithsonian Institution; Virginia Tech; Smithsonian Institution; North Carolina Museum of Natural Sciences sunnyjsh@vt.edu http://www.beam.vt.edu/sunnyjsh/

In nature, several seabirds (e.g. Gannets and Boobies) dive into water at up to 24 m/s as a hunting mechanism; furthermore, Gannets and Boobies have a slender neck, which is potentially the weakest part of the body under compression during high-speed impact. In this talk, we investigate the stability of the bird’s neck during plunge-diving by understanding the interaction between the fluid forces acting on the head and the flexibility of the neck. First, we use a salvaged bird to identify plunge-diving phases. Anatomical features of the skull and neck were acquired to quantify the effect of beak geometry and neck musculature on the stability during a plunge-dive. Secondly, physical experiments of an elastic beam as a model for the neck attached to a skull-like cone revealed the limits for the stability of the neck during the bird’s dive as a function of impact velocity and geometric factors. We find that the neck length, neck muscles, and diving speed of the bird predominantly reduce the likelihood of injury during the plunge-dive. Finally, we use our results to discuss maximum diving speeds for humans to avoid injury.

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