Marine biologists in the United States say a humpback whale has broken the world record for travel by any mammal, swimming at least 9,800 kilometres in search of a mate.
The researchers say the female humpback travelled from the Atlantic to the Indian Ocean, the ABC reports.
The whale was first photographed among a group of humpbacks at a breeding ground off Brazil's south-eastern coast on 7 August 1999.
By sheer chance it was photographed more than two years later by a commercial whale-watching tour at a breeding ground near off the eastern coast of Madagascar.
The whale was identified thanks to the distinctive shape of its tail and a pattern of spots on it.
Until now it was thought only males, rather than females, would be likely to wander such extreme distances in quest of a partner.
