The mammal's incredible journey from the coast of Brazil to Madagascar was more than twice as far as humpbacks usually manage on a single migration.The fact that she is a female makes it even more unusual, as they are usually far less adventurous than male humpbacks, the Daily Mail reported.
The whale was first photographed by researchers from a boat as she cruised off the east coast of Brazil in 1999.Just over two years later, she was one of a trio of whales spotted in the Indian Ocean off Madagascar's east coast by a commercial whale watch boat.
The whale was identified thanks to the distinctive shape of its tail and a pattern of spots on it.
But her extraordinary journey has come to light only after a recent analysis of the slides of her tail markings.
Dr Peter Stevick of the Hebridean Whale and Dolphin Trust, who carried out the research, said it was the longest documented movement by a mammal."This is about 2,500 miles longer than any previously reported movement between breeding grounds," said Dr Stevick.
"Why this whale made this journey we do not know. Both the habitats in Brazil and Madagascar are popular for breeding, so there would have been no particular preference for environmental reasons. It would not have been because the waters were warmer, or anything like that.
"We also do not know what happened to the whale between sightings, or where it has been since."
There are an estimated 80,000 humpback whales in the world who spend winters breeding and giving birth in the tropics. Then they head 3,000 miles north or south to the polar seas to feed.
Normally they return to the same spots each year. It is unclear if the whale's epic trip was deliberate or the result of a navigational accident . Adult humpback whales range in length from 39ft to 52ft and weigh about 36 tons. They get their name from their distinctive body shape.