Northern Elephant seals spend most of their time at sea. But, from December through March, they come ashore to mate and raise their pups on a number of islands off the coast of California and Mexico. Competition is fierce among the males. Each year only a few will win the right to breed and take charge of a harem of females. Jim Metzner traveled to Ano Nuevo island, near Santa Cruz, to bring us this story of sex, violence and scientific mystery.