CONTRARY to what biologists believed, sharks鈥� 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鈥檛 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鈥檚 wing (The Journal of
Experimental Biology, vol 203, p 2261). To keep from sinking, the shark
swims at a slight upward angle, Wilga says. 鈥淚t鈥檚 not the pectoral fins, but the
whole body acting as a wing.鈥�