The humpback is the fifth largest whale. A diet of krill (thumb sized prawn-like animals) and small crustaceans support its massive bulk. There are a number of different species of krill, although it isEuphausia superba which is the largest and most abundant in the Antarctic. The whales sieve food from huge amounts of water through specialised fringed mouth plates made of baleen. Baleen, also known as “whalebone” is not really bone, but is made of keratin, the same protein substance as our own hair and nails, and the horns of cattle. Instead of teeth, they have hundreds of thin, horny baleen plates attached to their upper jaws. The plates have bristly inner edges which intertwine to form a filtering mechanism. The humpbacks baleen is coarse and stiff, excluding the possibility of feeding on smaller forms of plankton. The scientific name for baleen whales, mysticetes, comes from the Greek word mystax which means moustache!
Baleen whales consume between 1 and 8 tones (2000 and 9000 pounds) of fish and krill a day! They do not feed all year round, however, but only during half of the year when they are in the cold, nutrient-rich waters of their antarctic summer feeding grounds. Approximately 25% of what they eat during the summer is stored in the form of fat to provide extra energy and insulation during their winter fast when they migrate to warmer waters.
Normally humpbacks feed by lunging forward at the surface or by rushing on their prey from below. They have also developed a technique involving the creation of a ‘bubble net’ to trap and concentrate the prey long enough for them to grab it. To do this, the whale starts below the surface, weaving a net of bubbles by forcing air out through their blowholes as they swim upwards in a tight spiral, finally surfacing open-mouthed right amongst the Humpback Whale Feeding.
Southern Humpbacks feed in the Antarctic in preparation for their lengthy northern migration when they abstain from feeding. Although they may be opportunistic feeders in the northern waters and feed occasionally on schools of small fish and prawns. They have been observed by some of the local whale boat skippers feeding at the northern tip of Fraser Island.