The humpback’s scientific name is Megaptera novaeangliae. Megaptera means ‘big wing’. This refers to its flippers, the largest appendages of any animal – up to 5 metres long and about a third of its length. The name ‘humpback’ came from whalers who noticed that, just before diving, this whale arched its back more than others, exaggerating the hump around its dorsal fin.
Humpbacks are black with variable white markings on the underside of the tail fluke. These markings, like flaking white paint, are unique to each whale. The large flippers are usually white. The head is knobbly with protuberances, and the whale’s jaw and throat grooves are often encrusted with barnacles.
One way humpbacks catch fish
Humpbacks have developed a technique known as bubble netting to catch fish. They swim beneath a school of fish and, spiralling round, release a string of bubbles from their blowhole. These form a net around the fish, and the whales then rise through the centre to surface, open-mouthed, catching their feast.
A clown and a songster
Humpbacks do a good deal of acrobatic clowning – flipper slapping and leaping out of the water to splash down on their backs. The males also produce the longest and most varied songs in the animal world – a complex sequence of whistles, rumbles, groans, moans and clicks, which can last for 20 minutes and be repeated over and over.
Humpbacks are occasionally seen off the New Zealand coast, swimming between the Antarctic, where they spend the summer feeding on krill, and the tropics, especially Tonga, where they breed in winter. They often used to travel north along the east coast of New Zealand and back southwards down the west coast, sometimes passing through Cook Strait.
One way humans caught humpbacks
In the early 1890s the Cook family of Whangamumu, Northland, noticed that humpback whales used to pass between a low-lying rock and cliffs near Cape Brett. They slung steel mesh nets between the island and the shore, and the whales became hopelessly entangled in the mesh, presenting an easy target for chasing boats.
In the 20th century whalers caught over 200,000 humpbacks in the southern hemisphere. Illegal Soviet whaling from the 1950s to 1970s contributed a quarter of that number. Between 1911 and 1964 New Zealand whalers, most of them based around Cook Strait, killed over 5,000 humpbacks.
Since the end of humpback whaling the numbers have only slowly increased, despite big increases in Australian waters. However, in 2015 during the Department of Conservation's annual four-week Cook Strait whale survey, 137 humpback whales were counted. This compared with 40 in 2008.