The whale shark is certainly not a whale, nor is it really much of a shark, at least not the snarly predatory kind often imagined with row upon row of serrated teeth. It’s not particularly fast either, and swaggers around the ocean at much the same casual pace of a sea turtle. And because it never has to surface for air, and regularly swims to depths of more than 3,000 feet, its breeding habits and migration patterns remain mostly a wonderful mystery. But one fact is indisputable: The whale shark is an absolute giant. At about 40 feet and 47,000 pounds, it’s the world’s largest fish, to be exact, and recently we had the rare privilege and pleasure of swimming with one.