Whales - Species | Antarctic Minke Whale

Antarctic Minke Whale - Balaenoptera bonaerensis

There are several differences between the Antarctic Minke Whale and the Common Minke Whale. The Antarctic Minke Whale is slightly larger than the Common Minke Whale, and the Common Minke Whale has a white band in the centre of each flipper. There are also some slight differences in body shape and colouration. The Antarctic Minke Whale is more robust than other large baleen whales, with its rostrum being very narrow and pointed with a single ridge on its head. It has a dark bluish grey back together with a contrasting pale grey belly and white flanks. It has a crescent shaped grey streak running up each side of the animal. Antarctic Minke Whales have asymmetrically coloured baleen, with the right side having a larger number of white plates than the left. They range from 7.2 to 10.7 meters in length and weighing approximately 5.8 to 9.1 tonnes. Females are usually about 1 meter longer than males.

The Antarctic Minke Whale is found in all oceans of the Southern Hemisphere. In summer, it lives close to the Antarctica, but in winter moves further north. Mature Antarctic Minke Whales feed primarily on the Antarctic Krill. It appears they do not feed much while in the breeding grounds of lower latitudes, but when they do feed their diet remains krill based. Krill are pelagic and tend to only occur on the top surface of the Antarctic waters, therefore these whales do not need to dive deep to feed on the oceans floor.

Mating occurs from June to December, peaking in August and September. Gestation lasts about 10 months with calving peaking during late May and early June in the warmer waters north of the Antarctic. Calves are born measuring 2.4 to 2.8 meters in length and while suckling upon their mother, they grow at a rate of about 1 centimeter per day. They are weaned at about 4 or 5 months when the calf has reached approximately 5.7 meters in length. Weaned calves probably feed upon copepods and small fish. Ovulation of the female Antarctic Minke Whale occurs about 4 months after the birth of her calf, which leads to a 14 month calving cycle.

The Antarctic Minke Whales are not very social, tending to swim alone or in pairs. However, large feeding groups of up to 400 individuals may form in the higher latitudes. Young males appear to be more solitary than mature males but have also been known to be curious creatures, often approaching boats from a distance. Male Antarctic Minke Whales reach sexual maturity at about 7.3 meters, females at 7.9 meters and at the age of about 7 to 8 years. These whales have been known to exceed 50 years of age. They are the prey of Killer Whales, with one estimate suggesting that Antarctic Minke Whales comprise of up to 85 percent of the diet of Killer Whales in the Southern Oceans.

This species of whale has undergone extensive population reductions with about 14 600 whales killed off the coast of Brazil, 1113 from South Africa and over 98 200 in the Antarctic feeding grounds between 1957 and 1987. Continued whaling, even at low levels, could seriously reduce the Antarctic Minke Whales population size in years to come.