" I couldn't help wondering where porpoises had learned this game of running on the bows of ships. Porpoises have been swimming in the oceans for seven to ten million years, but they've had human ships to play with for only the last few thousand. Yet nearly all porpoises, in every ocean, catch rides for fun from passing ships; and they were doing it on the bows of Greek triremes and prehistoric Tahitian canoes, as soon as those seacraft appeared. What did they do for fun before ships were invented?
Ken Norris made a field observation one day that suggests the answer. He saw a humpback whale hurrying along the coast of the island of Hawaii, unavoidably making a wave in front of itself; playing in that bow wave was a flock of bottlenose porpoises. The whale didn't seem to be enjoying it much: Ken said it looked like a horse being bothered by flies around its head; however, there was nothing much the whale could do about it, and the porpoises were having a fun time. "

― Karen Pryor , Lads Before the Wind: Diary of a Dolphin Trainer