Several hypotheses are proposed to explain the evolution of the sphyrnid cephalofoil but few have been empirically tested. Some suggest the cephalofoil acts like a canard to provide hydrodynamic lift and increase maneuvering capabilities. Another hypothesis is that the cephalofoil functions in prey manipulation. Other hypotheses involve potential advantages of spacing sensory structures across the surface or at the lateral ends of the cephalofoil. Another such hypothesis is that pores in the laterally expanded sphyrnid cephalofoil (shark's head) provide an electrosensory capability that maximizes search area coverage to increase the opportunity to detect food sources.
One of the nation's leading authors in hammerhead shark physiology has authored three studies that provide insight into these hypotheses. Stephen M. Kajiura, from the Department of Zoology and Hawaii Institute of Marine Biology, University of Hawaii at Manoa, Kaneohe, HI, the researcher behind "Head Morphology and Electrosensory Pore Distribution of Carcharhinid and Sphyrnid Sharks," originally published in Environmental Biology of Fishes 61: 125133, 2001; "Maneuvering In Carcharhinid And Sphyrnid Sharks: The Role And Non-Roll of the Hammerhead Shark Cephalofoil" (coauthored by Jesica B. Forni and Adam P. Summers) and Electroreception in Juvenile Scalloped Hammerhead and Sandbar Sharks" (with Kim Holland) Dr. Kajiura will summarize
Contact: Donna Krupa
American Physiological Society