Fast or slow? Study reveals differences in how humpback whales change tune

Researchers solve mystery of why southern hemisphere whales switch suddenly but in north it is gradual

From Abba's Mamma Mia stealing the crown from Queen's Bohemian Rhapsody to Rihanna's Diamonds knocking Psy's Gangnam Style off the top of the charts - even the catchiest song eventually becomes superseded by a new number.

But the phenomenon is not unique to humans: male humpback whales also sing - and change their tunes.