Scientists: Hammerhead has 'virgin birth' in zoo's shark tank By David Fleshler South Florida Sun-Sentinel May 23, 2007 A hammerhead shark captured in Florida Bay gave birth without sex, according to scientists who said they used genetic analysis to account for the mysterious appearance of a pup in a tank of female sharks. The research was to be published today in the British journal Biology Letters. The phenomenon, known among biologists as a "virgin birth," had been observed before among some snakes, lizards and birds, but never a shark, the scientists say. The issue arose in late 2001 at a...