Dwarf Minke Whale

The dwarf form has the most complex coloration of any baleen whale. Dark gray fields and capes alternate with light gray and white blazes, patches, and streaks. The dark gray spinal field lies above an ivory white ventral field. This spinal field extends down into a nape field, which separates a light gray rostral saddle and a light gray, triangular, usually forwardly peaked thorax patch. The nape field, in turn, extends even further down into a dark throat patch, which reaches down to the ventral pleats and extends back to the front of the pectoral fins. Further back the spinal field extends into a dark thorax field, which usually forms an inverted triangle between the thorax patch and the light gray flank patch. This flank patch can be separated into an anterior and posterior flank patch by a dark triangular or even wave-like flank infill. Finally, the dark peduncle field covers the posterior portion of the caudal peduncle to the tips of the dorsal side of the flukes, which are white ventrally and thinly bordered by dark gray.

Dwarf Minke Whale
  • Size

    The dwarf minke whale has similar proportions to the northern form, with an upright, hooked dorsal fin set about two-thirds the way along the back that is up to 32 to 34 cm (12.6 to 13.4 in.) in height. It has 55 to 67 ventral grooves. Its baleen – 18 to 20 cm (7 to 7.9 in.) in length – is mostly white, with up to 45 per cent of the posterior plates shading from black to dusky gray along their outer margins.

  • Feeding

    Blue whales feed almost exclusively on krill, though they also take small numbers of copepods. The species of this zooplankton eaten by blue whales varies from ocean to ocean. In the North Atlantic, Meganyctiphanes norvegica, Thysanoessa raschii, Thysanoessa inermis and Thysanoessa longicaudata are the usual food.

  • Life History

    Common minke whales are sexually mature at about six to eight years of age for females and about six to seven years for males.Females are promiscuous. After a gestation period of 10 months, a single 2.6 m (8.5 ft) calf is born – only one out of 79 mature females during a study of minke whales off Iceland had twin fetuses, an 8.7 m (28.5 ft). The calf is weaned after a period of six months. The calving interval is only a year, so females are often simultaneously pregnant and lactating. Females reach physical maturity perhaps as early as 13 years of age; another study suggested that growth ceases for both sexes when they have 15 to 20 growth layers in their tympanic bullae, which may correspond to about 15 to 20 years of age. Both sexes can live to about 50 years of age.

  • Behavior

    All of the dwarf minke whales caught off South Africa were taken singly. The majority of sightings of dwarf minke whales on the Great Barrier Reef involved either single whales (53.3%) or pairs (28.9%), with the maximum number of individuals in a group being eight. Four cow-calf pairs were seen as well. Individuals encountered on the various reef systems there often approached dive boats and circled them as well as the divers in the water. They were also seen breaching.Off Brazil, groups normally only consisted of one or two individuals, which actively avoided whale watching boats and fishing vessels. Here they were seen to associate with feeding flocks of seabirds, usually brown boobies but also kelp gulls and terns on occasion.