CONTRARY to what biologists believed, sharks’ fins do not create lift like
aeroplane wings. Because sharks sink if they stop moving, it was assumed that
they use their wing-like pectoral fins to keep themselves up. But now George
Lauder and Cheryl Wilga of Harvard University have shown that the pectoral fins
of a leopard shark don’t produce any lift as it swims.
Only when a shark alters course do the fins turn and generate lift, making
them more like the ailerons on a plane’s wing (The Journal of
Experimental Biology, vol 203, p 2261). To keep from sinking, the shark…
