Apparently Southern Pacific Humpback whales have incredible eyesight, brown eyes that can see up through the water. When they launch themselves out of the water and spin in the ai, or breach, they are thought to be checking they are travelling in the right direction.
They are attracted to bright colours and are friendly enough to swim up to a boatload of tourists even when local laws insist that the boats must not motor within 100 metres of the whales.
Once up close, they seem to be praying purely for our entertainment. They blow spray through their blowhole, circle us, slap their fins on the water and poke their noses out (spy-hopping). Scientist declare that slapping their arms around might be to remove irritating barnacles but I personally reckon they were just waving.