Blue Whale

Blue Whale



COMMON NAME: blue whale, sulpher-bottom
KINGDOM: Animalia
PHYLUM: Chordata
CLASS: Mammalia
ORDER: Cetacea
SUBORDER: Mysticeti
FAMILY: Balaenopteridae
GENUS SPECIES: Balaenoptera musculus


DESCRIPTION: Blue whales, named for their bluish-gray coloration, are known for their immense size. Their coloration often includes grayish or whitish areas. When viewed from above, the rostrum appears broad and U-shaped and a large splashguard surrounds two blowholes. A blue whale's slender, vertical blow can reach a height of 9 m (30 ft.). Blue whales have 55-68 vertical grooves extending back almost to the navel. The dorsal fin is very small and set ¾ of the way back and the trailing edge of the flukes are smooth except for a small notch in the center.
FEMALE Females tend to be slightly larger than males
SIZE: For adults, a maximum of 33.5 m (110 ft.), but lengths of 21 m (70 ft.) are more common. Blue whale calves measure about 7 m (23 ft.) in length.
MALE For Antarctic adults at physical maturity, lengths of 25 m (82 ft) are common; specimens from the Northern hemisphere are typically smaller
FEMALE For Antarctic adults at physical maturity, lengths of 27 m (88.6 ft) are common; specimens from the Northern hemisphere are typically smaller
WEIGHT: Long ago, Antarctic blue whales weighed 145,280 kg (320,000 lb.). Newborn calves weigh 2,700-3,600 kg (6,000-8,000 lb.).
DIET: Krill and occasionally pelagic crabs
GESTATION: 12 months
NURSING DURATION Calves are weaned at eight months, when they gain as much as 90 kg (200 lb.) a day
SEXUAL MATURITY: At about 6-10 years of age
LIFE SPAN: At least up to 30 years, possibly to well over 40 years
RANGE: Oceans worldwide, most abundant in eastern north Pacific
HABITAT: Primarily found along the edges of continental shelves and ice fronts
POPULATION: GLOBAL About 10,000-14,000
  LOCAL Off California, about 2,000
STATUS: IUCN Endangered
CITES Appendix I
USFWS Endangered


1. Blue whales belong to the cetacean suborder Mysticeti - the baleen whales. Whales in this suborder lack teeth. Instead, they have stiff, hair-like baleen plates that hang from their upper jaws. With the baleen plates, blue whales filter vast quantities of krill (tiny shrimp-like crustaceans), consuming as much as four tons per day.
2. Blue whales typically travel either singly or in pairs, although sometimes more whales may be found within close range in areas high in krill concentrations.
3. Blue whales are capable of producing low-frequency sounds, which can travel hundreds of miles in deep water. The function of these long-ranging vocalizations is not quite known although it is theorized that some of the vocalizations aid in navigation by imaging seamounts, islands and other underwater masses.
4. The blue whale is the largest animal in the world - probably the largest that ever lived. Long ago, Antarctic blue whales measured 30.5 m (100 ft.) and weighed 145,280 kg (320,000 lb.). Whale hunters took the most massive whales - the biggest blue whales today measure about 26 m (85 ft.), but lengths of 21 m (70 ft.) are more common. A blue whale's heart alone may weigh 908 kg (2,000 lb.), as much as a small car.
5. For more information about baleen whales, explore the BALEEN WHALES INFO BOOK.


Widespread commercial whaling during the 19th and 20th centuries, severely depleted blue whale populations. The current worldwide population is a fraction of the more than 200,000 blue whales that once roamed the seas.

Several U.S. and international treaties and agencies including the International Whaling Commission, the U.S. Marine Mammal Protection Act of 1972 and the U.S. Endangered Species Act of 1973 protect blue whales. But despite more than 50 years of protection, blue whale populations have not recovered.


Jefferson, T.J. Leatherwood, S. and M.A. Webber. FAO Species identification Guide. Marine Mammals of the World. Rome. FAO, 1993.

Leatherwood, Stephen, and Reeves, Randall R. The Sierra Club Handbook of Whales and Dolphins. San Francisco: Sierra Club Books, 1983.

Nowak, Ronald M. (ed.). Walker's Mammals of the World. Vol. II. Baltimore: Johns Hopkins University Press, 1991.

Parker, S. (ed.). Grizmek's Encyclopedia of Mammals. Vol. IV. New York: McGraw-Hill Publishing Co., 1990.

Reeves, R. R., Stewart, B.S., Clapman, P.J., and J.A. Powell (Peter Folkens illustrator). National Audubon Society: Guide to Marine Mammals of the World. New York: Random House, 2002.