Species: Balaenoptera musculus

Blue Whale

Species

Encyclopedia of Puget Sound

A very large (the largest living animal) baleen whale; body is mottled bluish gray; head is flat in front of the paired nostrils, broad and nearly U-shaped in dorsal view, with a single median ridge that extends forward from the raised area in front of the nostrils (ridge does not quite reach tip of snout); dorsal fin, located in the last quarter of the back, is very small; throat has 55-68 longitudinal grooves; belly may appear yellowish due to diatom accumulations; flipper are long and slim; baleen is black; potential maximum length is over 30 m, with the largest females averaging slightly longer than the largest males (Leatherwood and Reeves 1983).

Classification

Kingdom

Animalia

Phylum

Craniata

Class

Mammalia

Order

Cetacea

Family

Balaenopteridae

Genus

Balaenoptera

NatureServe

Source:
ELEMENT_GLOBAL.2.101880

Classification

Other Global Common Names

Ballena Azul - rorqual bleu

Informal Taxonomy

Animals, Vertebrates - Mammals - Whales and Dolphins

Formal Taxonomy

Animalia - Craniata - Mammalia - Cetacea - Balaenopteridae - Balaenoptera - .

Ecology and Life History

Short General Description

A baleen whale (the largest living animal).

Habitat Type Description

Marine

Migration

true - true - true - Most migrate to high latitude feeding areas for summer, return to lower latitude breeding areas for winter. For example, those that summer off Alaska winter off southern California and Baja California (IUCN 1991). There may be a basically resident or short distance migratory population off California and Baja California. Of individuals tagged off southern California, where apparently they were feeding or foraging, one moved to waters off northern California and four moved southward to Baja California, two passing Cabo San Lucas and one of these moving an additional 3000 km to near the Costa Rican Dome (an upwelling feature), which may be a calving/breeding area (Mate et al. 1999). Data on vocalizations support the idea that blue whales off North America and in the eastern tropical Pacific represent a single stock (Stafford et al. 1999). Hydrophone recordings suggest possible winter and late summer migrations off Oahu (Hawaii) (Thompson and Friedl 1982).

Non-migrant

true

Locally Migrant

true

Food Comments

Eats primarily krill. Feeding occurs primarily in high latitude waters.

Reproduction Comments

Mates May-September in the Northern Hemisphere. Gestation is reported as 11 or 12 months. Adult females bear one calf every 2-3 years. Young are weaned in about 8 months. Females reach sexual maturity in about 10 years. Maximum lifespan is uncertain; reportedly only about 20 years or up to 80-90 years.

Ecology Comments

Usually solitary or in pairs or threes; may congregate in good feeding areas.

Length

3050

Weight

1.36E8

Conservation Status

NatureServe Global Status Rank

G3G4

Global Status Last Reviewed

1999-12-01

Global Status Last Changed

1999-12-01

Distribution

Conservation Status Map

Global Range

H - >2,500,000 square km (greater than 1,000,000 square miles) - H - Occurs throughout the world's oceans. Three major breeding groups: North Pacific, North Atlantic, and Antarctic; perhaps a separate breeding population in the Indian Ocean. Seen with some regularity in deep coastal canyons off central and southern California, far inside the Gulf of St. Lawrence, and in the Denmark Strait. See IUCN (1991) for further details. For all practical purposes the Northern Hemisphere and Southern Hemisphere stocks do not mix (IUCN 1991). Subspecies BREVICAUDA (pygmy blue whale) is known mainly from subantarctic waters of the Indian Ocean and southeast Atlantic; reported also from other areas such as the northern Indian Ocean and off western South America.

Global Range Code

Global Range Description

>2,500,000 square km (greater than 1,000,000 square miles)

ELEMENT_GLOBAL.2.101880