Also called just a roll. Seeing a humpback do a full roll in the water is a rare event and I’ve only seen it twice. These photos of an unidentified whale from July 2, 2010, show the pectoral at the body and indicate the amount of effort involved in rolling this 40+ ton animal, even in the water! Judging by the size of the pectoral fin, this is a juvenile. Sometimes the whale simply rolls and the pectoral fins quietly slip into the water. Other times they make a large and noisy splash. I have found no explanation for this behavior and will not even hazard a guess. It is very fun to watch and I’d like to see it more often!