Humpback whales have a type of brain cell seen only in humans, the great apes, and other cetaceans such as dolphins, US researchers reported on Monday. This might mean such whales are more intelligent than they have been given credit for, and suggests the basis for complex brains either evolved more than once, or has gone unused by most species of animals, the researchers said. The finding may help explain some of the behaviour seen in whales, such as intricate communication skills, the formation of alliances, cooperation, cultural transmission and tool usage, the researchers report in the Anatomical Record.