Humpback Whale

Megaptera novaeangliae

Key Facts

Size: Female up to 19m, Male 11 - 17m

Range: Tropical to Polar waters worldwide

Threats: Caught in fishing nets, human disturbance

Diet: Krill, sardines, herring and other small schooling fish

Physical description

The humpback whale is very easily distinguished from other baleen whales by its distinctive knobbly head and the dorsal fin which is reduced to a fleshy hump or hook on a broad base set far back along its spine. The pectoral fins are huge (Megaptera means “great wing”) and may be as much as a third of the body length. These are also knobbly and usually white on both sides, though the pacific humpbacks fins are more often black on the upper surface. The body is blue-black with white patches underneath. The knobs or protuberances on the head are enlarged hair follicles and are often full of parasitic barnacles and lice. There are twelve to thirty-two deep throat grooves and its baleen is both long and wide. The tail fluke is black and white in distinct patterns and they have a clear notch and irregular trailing edges.

Distribution

Humpbacks are very wide-ranging and are found in all oceans at the edge of the ice packs but they show distinct seasonal changes in distribution. Groups of four to twelve animals are common, moving to the warmer tropical waters in winter and back to the cold-water feeding grounds in the polar waters in summer. They follow the shoals of small schooling fish and can be found in shallow inland waters as well as in the open oceans.


Behaviour

Usually seen singly or in pairs or in small groups up to 15 individuals. They are very energetic and are well-known for their displays of breaching and lob-tailing. They dive for about 5-10 minutes but this can be up to 45 minutes and before a long dive they raise their tail flukes. They are very inquisitive and move near to boats where they will often spy hop and flipper-slap and seem to perform specially for the watchers!

Breeding

As with most rorquals, the female is larger than the male and matures when about 12 metres long in both sexes. Breeding takes place in the warm tropical waters where calves are born in winter every two or three years. Mothers and their calves stay close for the first year. The males can sometimes be very aggressive towards each other and during the breeding season they produce the longest and most complex songs of any animal.

Feeding

Humpbacks apparently feed only in colder waters and feed on krill, sardines, mackerel, anchovies and other small schooling fish. They have a range of feeding techniques including bubble-netting where a group of whales produce a ring of bubbles, driving the fish together and up towards the surface where they can be caught in huge gulps.

Current situation

More than 250,000 humpbacks were killed by whalers and although some populations seem to be recovering, there are very few animals compared to the original numbers. Being inquisitive and certainly not afraid of boats, humpbacks are at great risk of being caught in fishing nets as well as being tangled in marine pollution.

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