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Species AbstractThe Northern minke whale (Balaenoptera acutorostrata), is a very large cetacean, in the family of Rorquals (Balaenoptera). The Minke is a baleen whale, meaning that instead of teeth, it has long plates which hang in a row (like the teeth of a comb) from its upper jaws. Baleen plates are strong and flexible; they are made of a protein similar to human fingernails. Baleen plates are broad at the base (gumline) and taper into a fringe which forms a curtain or mat inside the whale's mouth. Baleen whales strain huge volumes of ocean water through their baleen plates to capture food: tons of krill, other zooplankton, crustaceans, and small fish.
The smallest of the rorqual whales (and the second-smallest baleen whale), the minke whale is also the most abundant. Two species are now recognised, the northern hemisphere minke whale (the subject of this species page) and the southern hemisphere Antarctic minke whale (Balaenoptera bonaerensis). Minke whales are slim in shape, with a pointed dolphin-like head, bearing a double blow-hole. The smooth skin is dark grey above, while the belly and undersides of the flippers are white, and there is often a white band on the flipper. When seen at close quarters, minke whales have variable smoky patterns which have been used to photo-identify individuals.
Minke whales feed on fish and various invertebrates; like all baleen whales they filter their food from the water using their baleen plates like sieves. Although largely a solitary species, when feeding minke whales can often be seen in pairs, and on particularly good feeding grounds up to a hundred individuals may congregate. A number of feeding techniques have been observed, including trapping shoals of fish against the surface of the water. After a ten month gestation period, births occur in mid-winter, at birth the calf measures up to 2.8 metres in length. It will be weaned at four months of age, and will stay with its mother for up to two years, becoming sexually mature at seven years of age. Minke whales have an average life span of around 50 years. Minke whales are rather inquisitive and often swim by the side of boats for up to half an hour.