In common with other rorquals (baleen whales with throat grooves), Humpback whales exhibit a range of behaviours, including tail slapping, spyhopping, porpoising, breaching and pectoral slapping.
The exact meaning of this behaviour is still not fully understood, but behaviour such as breaching may involve demonstrations to other whales to indicate territory or dominance. Behaviour such as lobtailing may be used to school fish into tighter shoals for feeding. Whales also appear to have a good sense of play.
The exact meaning of breaching is unclear, but may serve several purposes, including dislodging barnacles, as a threat display, as a means of alerting other whales to their presence and for play. There are both forward and backwards breaches, and the body may leave the water entirely or not.