A humpback whale and her calf visited Nuku'alofa last Friday, July 25, the Tonga Visitor's Bureau reports, with sightings of the pair unusually close to the shores of the capital.

Humpback whales were on their annual voyage to the warm waters of Vava'u where they mate and to give birth.

Tongan superstition, however, had something else to say about the visit, "the mother and calf dropped by to wish the king good luck," stated the Visitor's Bureau.

The humpback whales of Tonga are part of the Southern Hemisphere group of humpbacks. The whales feed in Antarctica during summer, and travel north past New Zealand to Tonga. Other humpbacks travel the east coast of Australia, wintering in the waters of the Great Barrier Reef.

Humpbacks can be identified by the patterning on their flukes (their tails), which are unique to each whale, like fingerprints. Efforts to identify and track individual whales have helped to confirm the success of whale conservation programs, implemented when the commercial whaling of humpbacks was banned in the Southern Hemisphere in 1963.

Humpback whales do not reach sexual maturity until they are around seven years of age, and the gestation period is 12 months. A newborn humpback whale is more than four metres long. The calf who visited Tongatapu with her mother last week would have been born last year, because whale calves stay with their mother for a year after they are born, and mothers generally breed only every second year.

A mother humpback raises her head briefly. The characteristic bumps, called tubercles, are actually hair follicles. Photo courtesy TVB.

A young calf launches itself from the water, which is called breaching. Humpback whales are the most athletic species of whale, entertaining thousands of whale watchers each year. Photo courtesy TVB.