Origin

Dwarf minke whales, commonly regarded as subtypes of the northern minke whales, were first described in the mid 1980s even though there is still little known on them. This was after they attracted attention from scientists for frequently approaching waters in the northern Great Barrier Reef disrupting swimmers.

The word “minke whale” basically refers to a name given to two marine mammal species but arising from a “clade”. This name originates from the Norwegian word “minkehval”. Mink whales, following modern classification, are categorized by taxonomists into two main species:

  • The common minke whale, the northern minke whale or Balaenoptera acutorostrata
  • The Antarctic minke whale, also regarded as the southern minke whale or Balaenoptera bonaerensis.

Scientists have further classified the common minke whale species into three subtypes; the North Pacific minke whale, the North Atlantic minke whale and the dwarf minke whale. It is also very important to note that all minke whales are part and parcel of the rorquals, a family that comprises of the fin whale, the humpback whale, the sei whale, the blue whale and Bryde’s whale.

Description

  • Length: It is on record that dwarf mink whales are the second smallest type of Baleen whales just after the pygmy right whale. Upon maturation (that is after 6-8 years), males measure up to 6.9 m (about 23 ft) while females measure an average of 7.4 m (about 24 ft) long, respectively. These lengths however can range from 8.8m to 9.8 m (29-32 ft) in males and 9.1 to 10.7 m (30-35 ft) in females.
  • Weight: Both sexes on average weigh between 4 to 5 long tonnes and between 4.4-5.5 short tonnes although they can weigh up to 10 tonnes.
  • Appearance and color: A typical minke whale bears a black/purple or grey color. To distinguish them from other whales, the Northern Hemisphere varieties have a white band embedded upon each flipper. Their bodies are generally dark-grey or black with a white band underneath. They actually have between 240 -360 baleen plates on each side, and thus the origin of the name ‘baleen whales’.

On the contrary, dwarf minke whale’s shoulder is whitish but with a flipper base having a dark-grey tip. Unlike northern minke whales, the dwarf minke whale has a huge protruding patch making its way to the throat.

Location and Distribution

Dwarf minke whales have so far been described in the Southern Hemisphere only as well as Antarctic as opposed to the Northern Hemisphere (where common minke whales are found). They are commonly found in Australian waters as well as waters of New Zealand, Vanuatu, South Africa, South Africa, Caledonia and east coast of South America. In Australian, they are present in almost all states except Tasmania but not at all in the Northern territory. Moreover, they frequent the Swains Reefs and the north of Lizard Island which are part of the Great Barrier Reef.

Age and Breeding

The life span of dwarf minke whales is so far unknown although other minke whales, according to scientists, live between 50-60 years. Their life spans are projected by physically finding the estimate number of waxy plug layers around the ear drum. New layers are ideally deposited every year. They reach sexual maturity after 6-8 years when they are 6.5 m long. Based on facts known about other minke whales, dwarf minke whales probably give birth to one 2 m long calf each year and suckle them during those early ages with milk containing about 30% fat. Calves are usually weaned between 5-6 months after birth.

Gender

In most toothed whales, northern minke whales, males are larger than their female counterparts and have different fin and body shapes. On the contrary, the dwarf type of minke whales are not easily distinguishable. The shape and position of the genital slit is the only thing that can distinguish the two. For example, in males the slit is more projected forward and obviously separated more from the anus.

Feeding

Other huge whales, like the humpback, migrate to the higher latitudes to feed and move back o the lower latitudes to calve and nurse. However, little is known as regards the feeding patterns of dwarf whales.