77. How fast can a porpoise swim? Is it the fastest swimming 

 "fish"? 



Most porpoises can swim 17 to 23 miles per hour for short periods, 

 although, to an observer aboard a ship, they may appear to be traveling 

 much faster. There are records of porpoises being observed at 40 to 43 

 miles per hour, but they were swimming before a ship, utilizing the bow 

 wave for extra speed. 



Much research has been done to discover just how the porpoise is 

 able to accomplish its high swimming speed. Either it is a much more 

 powerful swimmer than expected, or it modifies its shape and, there- 

 fore, reduces hydrodynamic drag. The question is yet unsolved. 



Although the porpoise is a very fast swimmer, it is not the fastest sea 

 animal. Marlin, bonito, and albacore have been reported to swim at 

 speeds of 40 to 50 miles per hour. The sailfish and swordfish have at- 

 tained speeds of 60 miles per hour. 



Alpers, Antony 



Dolphins: The Myth and the Mammal, Houghton Mifflin Com- 

 pany, 1961. 



Lagler, Karl F., J. E. Bardach, and R. R. Miller 

 Ichthyology, John Wiley and Sons, 1962. 



Norris, Kenneth S. 



Whales, Dolphins, and Porpoises, University of California Press, 

 Berkeley and Los Angeles, 1966. 



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