STONY BROOK, N.Y., May 1 (UPI) -- Sand tiger sharks compete with each other while still in the mother's womb, turning to cannibalism until only one survives to be born, U.S. researchers say.
Marine biology professor Demian Chapman of Stony Brook University in New York said when a female shark gets pregnant, it's usually with multiple offspring of several different male sharks, but as soon as the fetuses are old enough, they begin a cannibalistic battle for survival.