Humpback whales are baleen whales, filtering food through a series of bony plates about 25 inches long.  The humpback takes in water in a huge mouthful containing krill, then pushes the water out sidesways, swallowing the krill.  In one day a whale may ingest a tonne and a half of food.  Most of the humpback's feeding takes place in Summer in the cold Antarctic waters, providing enough food reserves, in the form of blubber, to last up to eight months of the year.  Males are an average of 16m long, and females slightly longer at 17m.

The Humpback's migratory path covers 3,600km from the feeding grounds of the Antarctic to the calving grounds of the Kimberley.  The population found off Western Australia is known as the Group lV population, with the Eastern Australian population known as the Group V population.  When whaling ceased in 1963, the Western Australian population of Humpbacks was thought to number no more than 500 individuals.

Humpbacks, like all other cetaceans, are true mammals.  Mating and calving takes place in tropical waters from June to November, and at latitudes of between 12 and 25°S.  "The northern endpoint of migration and resting area for reproductively active whales in the population appears to be Camden Sound in the Kimberley. A 6,750 square km2 area of the Kimberley region, inclusive of Camden Sound, has also been identified as a major calving ground"1.  The peak time of Northern migration appears to be the last week in July.  Its was thought that the whales appeared to pass to the West of the Lacepede islands, remaining offshore until they reach Camden Sound, but observations this year suggest that they may in fact move in to the coast more to the South, from Broome to James Price Point.

Gestation takes eleven months, with calves born at a length of four to five metres,  and a weight of two tonnes.  After birth, the mother will provide nearly 240 litres of milk per day for the calf, feeding the calf for nearly a year.  The milk is extremely rich, approximately 40-50% milk fat and the consistency of chewing gum. By the time the calves are weaned at 11 months, they will have doubled their length to about nine metres.

Sound is of tremendous importance in humpback communication, and they are thought to produce approximately 640 different vocalizations.  Male humpbacks "sing" complex songs comprised of verses and sets, but females and calves also communicate by sound. 

"There's a lot of very close tactile relationship goes on between a cow and a calf" says Micheline Jenner, from the Centre For Whale Research.  " That's the strongest bond in humpback society. It's very interesting to watch they are quite beautiful. They swim very closely together, the cow will remain horizontal at the surface resting and the calf will often lie perpendicular to her, under her chin, underneath the water. Or actually, sometimes we've seen a calf actually caught under the flipper of an adult humpback whale. That looks really funny when you see a calf sort of stuck under there and the female will just remain still and the calf will then sort of scoot out from underneath the flipper and then pop to the surface like a cork, take a breath and then dive down again. And then they position themselves right across the underside of the belly. At other times you can see a calf lying on the head of the female and you can see the females, the cows are really quite patient and I guess that's how mums are".

Humpback whales are so named from the manner in which they 'hump' their backs when they dive.

Click here for the American Cetacean Society’s fact sheet on Humpbacks.

1.Jenner, K.C.S., Jenner, M-N., and McCabe K.A. (2001).

Geographical and temporal movements of humpback whales in Western Australian waters. APPEA Journal 38 (1):692-707. PDF Download 1.3mb