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Spinning makes safe dive: cape gannet

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Northern Gannet / Andreas Trep.. / LicenseCC-by-sa - Attribution Share Alike

The body of a diving gannet enters the water safely at 100 km/h by spinning.

BIOMIMICRY TAXONOMY
Summary
"Depending on the altitude of the attack and on the wing effort during the first phase of the nosedive, gannets hit the water with speeds of 40-120 kilometers per hour… How does the gannet avoid veering off course and tumbling over during the dive and the dangerous moment of penetration? At 100 km/h, a slight gust, one wrong move, or rough seas could seal its fate. The secret was revealed by slow-motion photography: While diving, the gannet puts itself into a spin with a deliberate tail movement. The spin increases toward the point of impact as the bird lays back its wings like a figure skater bringing her arms close to her body. In a fast dive, this movement usually turns the body once or twice around its axis, acting like a gyroscopic stabilizer in a rocket. In the language of physics, the bird is kept on course by the conservation of angular momentum. This elegant mechanical stabilization notwithstanding, the moment of impact on the water surface is critical because of the powerful forces involved. But the gannet has been well primed by nature for this moment. Its body can stretch into an ideally streamlined spindle. Any unevenness about the head is eliminated. At the moment of immersion, the gannet draws in its neck slightly so that the pointed beak and the flat top of the head form a straight continuous line with the body, creating a cone which combines low resistance with high stability. The maze of air cells between the skin and the muscles, directly or indirectly connected with the lungs, receive and distribute whatever pressures occur." (Tributsch 1984: 88-89)

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About the inspiring organism
Cape Gannet
Morus capensis (Lichtenstein, 1823)

Habitat(s): Marine Coastal/Supratidal, Marine Neritic, Marine Oceanic
Learn more at EOL.org
Some organism data provided by: ITIS: The Integrated Taxonomic Information System
Organism/taxonomy data provided by:
Species 2000 & ITIS Catalogue of Life: 2008 Annual Checklist

Threat Categories LONG_VU IUCN Red List Status: Vulnerable

Bioinspired products and application ideas

Application Ideas: Increased aerodynamics for vehicles or other machines that move at high speeds, especially from one medium into a thicker one (e.g., air into water).

Industrial Sector(s) interested in this strategy: Transportation, manufacturing

References
Tributsch, H. 1984. How life learned to live. Cambridge, MA: The MIT Press. 218 p.
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