MIGHTY FLIPPERS: Dolphins are able to swim so rapidly by generating large amounts of power from the oscillations of their flukes.COURTESY OF FRANK E. FISH
Writing in the Journal of Experimental Biology in 1936, British zoologist James Gray made a simple calculation based on observations of a dolphin swimming alongside a ship in the Indian Ocean. The dolphin, he reported, had passed the vessel, from stern to bow, in 7 seconds. The ship was 41 meters long and it was moving at 8.5 knots. “This dolphin must therefore have been travelling at 20 knots [10.1 meters per second],” wrote Gray, who concluded, after an avalanche of more complex calculations, that dolphins couldn’t possibly have attained that speed using muscle power alone.
In an attempt to resolve the quandary, which became known as “Gray’s paradox,” he suggested that dolphins must use some trick of fluid dynamics to overcome drag, the opposing ...
