Minke whales (Balaenoptera acutorostrata and Balaenoptera bonaerensis) (or Lesser Rorqual) are the smallest of all the Rorquals in the Baleen family (only the pygmy right whale is smaller). The Common Minke Whale has three subspecies: the North Atlantic Minke Whale, the North Pacific Minke Whale and Dwarf Minke Whale. Male Minke whales reach a length of around 8 – 10 metres and females 8 – 10.5 metres.
Both male and female Minke whales typically weigh 4 – 5 tons at maturity and the maximum weight may be as much as 14 tons. The gestation period for minke whales is 10 months and babies measure 2.4 to 2.8 metres (7 feet 10 inches to 9 feet 2 inches) at birth. The newborns nurse from their mothers for five months.
The body of the Minke whale is usually black or dark-grey above and white underneath. Most of the length of the back, including dorsal fin and blowholes, appear at the same time when the whale surfaces to breathe, which reveals the small size of the animal. On surfacing from a deep dive, the whale then breathes 3 – 5 times at short intervals before ‘deep-diving’ again for 2 – 20 minutes. Deep dives are preceded by a pronounced arching of the back.
The maximum swimming speed of minkes has been estimated at 20 – 30 kilometres per hour. Minke whales have between 240 and 360 baleen plates on each side of their mouths. Minke whales typically live for 30 – 50 years, however, in some cases they may live for up to 60 years. Minke whales are very tolerant and often approach vessels.
Minke whales conservation status is classed as ‘near threatened’. The IUCN list the northern species as Lower Risk/Near Threatened and the southern as Lower Risk/Conservation dependent. The dwarf minke whale (B. acutorostrata subspecies) has no population estimate, and its conservation status is categorised as ‘data deficient’.