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Balaenoptera acutorostratacommon minke whale

By Bridget Fahey

Ge­o­graphic Range

Minke whales have a world­wide dis­tri­b­u­tion, ap­pear­ing in all oceans and some ad­join­ing seas. Cooler re­gions seem to be pre­ferred over trop­i­cal re­gions.

Habi­tat

Al­though not con­sid­ered "coastal", these baleen whales rarely ven­ture far­ther than 169 km from land. They also com­monly enter es­tu­ar­ies, bays, fjords, and la­goons. They are also know to move far­ther into polar ice fields than other rorqual species.

Phys­i­cal De­scrip­tion

Minkes are the small­est of the fin­back whales, grow­ing to a max­i­mum of 10.2 me­ters long. Fe­males are larger than males, oc­ca­sion­ally grow­ing to a max­i­mum of 10,000 kg. Col­oration is dark above with a white un­der­belly. The head is pointed and bul­let­like, with a rel­a­tively small ros­trum. Baleen plates num­ber around 300, are yel­low­ish in color, and oc­ca­sion­ally as­sy­met­ri­cal in pat­tern. There are be­tween 50-70 ven­tral grooves. A broad white band trims the dor­sal side of flip­pers. The tail ex­tends into two long tips. The dor­sal fin is high and curved back.

  • Range mass
    6000 to 9000 kg
    13215.86 to 19823.79 lb

Re­pro­duc­tion

Only one young is born at a time. Ges­ta­tion lasts for 10 to 11 months. Weight at birth is 450 kg. The young are weaned at 5 months, but they do not be­come sex­u­ally ma­ture for 6 years. Fe­males are thought to have young every other year. The breed­ing pe­riod is long--from De­cem­ber to May in the At­lantic and year round in the Pa­cific. Peak months for births are De­cem­ber and June. Growth stops at about 18 years for fe­males and 20 years for males.

  • Breeding interval
    Females are thought to have young every other year.
  • Breeding season
    The breeding period lasts from December to May in the Atlantic and year round in the Pacific
  • Average number of offspring
    1
  • Average number of offspring
    1
    AnAge
  • Range gestation period
    10 to 11 months
  • Average age at sexual or reproductive maturity (female)
    6 years
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    2740 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    6 years
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    2740 days
    AnAge

Lifes­pan/Longevity

Be­hav­ior

Minke whales travel ei­ther singly or in small groups (2-4), al­though they can be found in large ag­gre­ga­tions in the hun­dreds where krill is abun­dant. They are thought to be cu­ri­ous, ap­proach­ing ships and wharfs which is not typ­i­cal of its fam­ily. They are also highly ac­ro­batic, able to leap com­pletely out of the water like a dol­phin. Minkes are fast swim­mers. Some pop­u­la­tions are mi­gra­tory--both south­ern and north­ern pop­u­la­tions often spend win­ter in trop­i­cal wa­ters, al­though these are ac­tu­ally at dif­fer­ent times of year as a re­sult of sea­sonal dif­fer­ences in their home­lands.

Com­mu­ni­ca­tion and Per­cep­tion

Food Habits

A baleen whale, this species feeds pri­mar­ily on krill and some small fish. There are re­gional dif­fer­ences in the diet. Minkes eat krill al­most ex­clu­sively in the Antarc­tic, but they are more om­niv­o­rous in the north­ern hemi­sphere, tak­ing as food squid and small ver­te­brates such as cod, her­ring, and sar­dines.

  • Primary Diet
  • carnivore
    • eats non-insect arthropods
  • Animal Foods
  • fish
  • mollusks
  • aquatic crustaceans

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Minke whales have been hunted by peo­ple for prod­ucts such as meat, oil, and baleen since the Mid­dle Ages. Re­gard­less, it has never been of large com­mer­cial im­por­tance until other whale species were over­hunted. An­nual kill peaked in 1976 with 12,398 in­di­vid­u­als, but now is down to < 1,000. These are taken pri­mar­ily by in­dige­nous peo­ples for food, or by sci­en­tists for re­search.

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

None.

Con­ser­va­tion Sta­tus

The global pop­u­la­tion is es­ti­mated at over 300,000 in­di­vid­u­als, and there seems to be no cause for con­cern, since this species is not com­monly hunted any­more. Many pop­u­la­tions are on ap­pen­dix 1 of CITES. Num­bers have also been on the rise since the early 1900's be­cause close com­peti­tors (other rorqual species) have been over­hunted.

Other Com­ments

A sec­ond form of minke whale called the dwarf minke has been found off Aus­tralia/ New Zealand/ South Africa. There is de­bate as to whether this is a sub­species of B. acu­toros­trata or a dif­fer­ent species al­to­gether.

Con­trib­u­tors

Brid­get Fahey (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor.

Glossary

Arctic Ocean

the body of water between Europe, Asia, and North America which occurs mostly north of the Arctic circle.

Atlantic Ocean

the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.

World Map

Pacific Ocean

body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

coastal

the nearshore aquatic habitats near a coast, or shoreline.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

filter-feeding

a method of feeding where small food particles are filtered from the surrounding water by various mechanisms. Used mainly by aquatic invertebrates, especially plankton, but also by baleen whales.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

migratory

makes seasonal movements between breeding and wintering grounds

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

solitary

lives alone

tactile

uses touch to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year

Ref­er­ences

Nowak, R.M. Walker's Mam­mals of the World, 5th Edi­tion. Johns Hop­kins Uni­ver­sity Press.

Grize­mek's En­cy­clo­pe­dia of Mam­mals. Mc­Graw-Hill Pub­lish­ing Co.

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Classification

Classification

  • Kingdom Animalia animals
  • Phylum Chordata chordates
  • Subphylum Vertebrata vertebrates
  • Class Mammalia mammals
  • Order Cetacea dolphins, porpoises, and whales
  • Family Balaenopteridae rorquals
  • Genus Balaenoptera rorquals
  • Species Balaenoptera acutorostrata common minke whale