Penguins are very agile swimmers and able to turn within one body length. Scientists from Tokyo Institute of Technology filmed Gentoo penguins swimming in an enclosure at Nagasaki Penguin Aquarium to see how they manoeuvre underwater. The researchers analysed the movement of the penguin wings and body and worked out the hydrodynamic forces involved.
They found that penguins turn with their belly facing the inside of the turn, unlike flying birds and aeroplanes, which turn with their bellies facing the outward side of the turn. They also use a combination of upward flapping and pronating (inward rotation) the inside wing, and asymmetrical movement of their two wings to generate centripetal force – the force that keeps an object moving in curve.
Reference: Inside JEB 22 December 2022; Journal of Experimental Biology 22 December 2022, doi: 10.1242/jeb.244124
Editorial Comment: The usual evolutionary story is that penguins use their wings in a flying movement like aerial flying birds they supposedly evolved from. However, moving in water is very different to moving in air, and the apparent similarities in wing movement of swimming penguins and flying birds are only superficially true. When penguins swim forwards the upstroke of their wings, rather than the downstroke, generates more forward propelling force than the downstroke.
This new study confirms that penguins also turn differently to aerial flying birds. The fact that penguins turn differently to aerial birds and aeroplanes may seem like a piece of useless trivia, but it is a good reminder that penguins were created to be fully functional penguins, designed to swim underwater and therefore to know how to use the appropriate hydrodynamic forces with their wings and bodies.
Creation Research News 31 January 2023
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