Tagged animals have revealed many of Norfolk Island's tiger sharks migrate 600 miles to New Caledonia, a French territory, in the autumn. But although there was a consistent pattern with sharks migrating between Norfolk Island and New Caledonia, their routes varied wildly. Now, the scientists know where these massive sharks are going, they want to figure out why. One theory is that the sharks mate near Norfolk Island and give birth in the waters of New Caledonia, which is in the open ocean, far from many predators.