One of the disadvantages of being stranded on a desert island with other people... sooner or later somebody's going to try and eat you. Here's a survival tip: as soon as you get on the island start eating everyone else. You're guaranteed to live longer than anyone else that way - maybe not long, but longer. If the others get mad at you just explain that it's a waste not to eat the dead guy now. "There's starving kids in Africa who'd be happy to have any food at all!" I think we've all heard that one...