Sea lion’s use their foreflippers as a static wing while maneuvering

California sea lions are one of most maneuverable mammals in water, with observed turning rates of 690°/sec and low turning radii at high speeds. Unlike most biological swimmers that use a body/caudal fin (BCF) type of locomotion, sea lions produce thrust by adducting their foreflippers into their body, which is followed by a long glide in a streamlined position. However, here we demonstrate another function for the foreflipper which involves the sea lion using it as a lift producing static wing that helps generate the necessary torque for agile maneuvers. Cross sections of the flipper model resemble the shape of the airfoils typically found in wings with thickness ratios, 11% - 37%. Wind tunnel testing on a laser scanned 3D printed foreflipper revealed that it produces lift over a wide range of angle of attacks, including negative angles. To complement the aerodynamic testing, surface oil flow visualization and near surface particle image velocimetry were conducted on the flipper. Results showed a complex three-dimensional flow structure over the flipper with areas of heavy crossflow.