Another photo by Gary Wilson showing a humpback whale tail lobbing or slapping. Most of the behaviour of Humpback whales remains a mystery, and tail lobbing is no exception. We have watched Humpback whales raise their huge fluke out of the water and slap it on the surface multiple (ten to twenty) times. It seemed playful, but no one knows exactly why Humpback whales perform this action. It is thought that it may have something to do with communication. The tail lobs apparently can be heard for a long distance underwater.