3     How do the Humpback whales catch these small creatures?

ABOVE: The baleen plates can be clearly seen in this picture of a humpback with its mouth open, taken in Hervey Bay in 1997. (Photo: Trish Franklin)

Humpbacks are baleen whales which means they have fibrous plates of baleen which hang like curtains from their upper jaw instead of teeth (See INSERT below). There are as many as 300 to 400 baleen plates on either side of their mouth, which act as a filter separating the krill from the sea water. Baleen, which is made of keratin just like our fingernails, is an extremely efficient sieving device for catching the many tons of krill needed to sustain them on their long migratory journey to the sub tropics and back.

INSERT: Pre-natal development of teeth and baleen in whales

"Late in the fetal period, both odontocetes [toothed whales] and mysticetes [baleen whales] form tooth buds.[...] The mysticete tooth buds [...] are usually resorbed before birth. The formation of rudimentary baleen plates, which occur concurrently with tooth bud degradation, may be induced by the process of tooth bud resorption (Ishikawa and Amasaki, 1995). As the mysticete fetus grows, longitudinal baleen ridges form in the gum and the upper jaw. These longitudinal ridges develop transverse divisions and rows of papillae composed of epidermal folds that become cornified. The cornified papillae are tubular in shape and elongate and coalesce with their neighbor to form baleen plates (Slijper, 1979)." Scource: Encyclopedia of Marine Mammals, 2000. [Editors: Perrin, Wursing and Thewissen]