Tropical tune has whales swimming to the same beat

The humpback whales off eastern Australia have become involved in a bit of plagiarism, stealing songs from visiting whales and using them for themselves.

Each species has its favourite tune, and different songs are sung by members of the same species when separated. Now scientists from the University of Sydney have discovered that a few blow-ins from the Indian Ocean have got all the Aussie humpbacks off the Pacific east coast singing the same tune.

The research is described today in the journal, Nature, as a "cultural revolution" in whale song. Male humpbacks sing while migrating to and from their feeding grounds, and their songs are also thought to be a form of sexual display. The researchers noted the change in the No 1 tune while recording whale song in the Pacific off the east coast. In 1995 and 1996 they noticed a slight change in the song used by 80 humpbacks after the arrival of just two others, who sang a completely different number.

After just a year the new tune had become popular and was being repeated at the expense of the original song. By 1998 the entire group had abandoned the original in favour of the new.

The researchers found that the new song was "nearly identical" to the song of humpback whales found along the west coast of Australia in 1996.

"Their song was replaced rapidly and completely by the song of the Australian west coast population from the Indian Ocean, apparently as a result of the introduction of only a small number of `foreign' singers."

In the end the scientists put the change down to novelty. It seems the whales just wanted something new.

A humpback whale in waters off Jervis Bay, 100 miles south of Sydney. Photograph: Tony Karacsonyi/AP