Humpback whales, like this one in Hawaiian Islands Humpback Whale National Marine Sanctuary, have the longest flippers of any cetacean. (They're roughly one-third the whale's body length!) The leading edge of these lengthy flippers aren't smooth; instead, they have bumps called tubercules on them. These tubercules make the humpback whale flippers more hydrodynamic, increasing humpback whale agility and helping the whales maneuver when catching fish. Researchers are studying this flipper shape to understand how to make more efficient wind turbines!