there is a population which lives near spain and portugal and which has specialized on attacking sailboats. they do not attack powerboats. this behaviour is mystery, as the whales cannot use glassfibre as a food. most likely the whales practice attacking large sharks and whales, as the underside of a sailing boat resembles a large whale or a shark. they have damaged several boats, but so far none has sunk and no humans have died on their attacks.