Sunday 19 May
Blue whale (Balaenoptera musculus)
- The blue whale is the largest animal to have ever lived!
- The heart of the blue whale is the size of a small car and can weigh up to 900 kg!
What’s the World’s Favourite Species?Find out here.
Blue whale fact file
- Find out more
- Print factsheet
Blue whale description
The blue whale (Balaenoptera musculus) is the largest animal to have ever lived, being almost as big as a Boeing 737 (2) and even larger than the biggest dinosaurs (6) (7). The largest recorded length for a blue whale is 33.5 metres (6), although most individuals vary between 24 and 27 metres (2). The heart of this monstrous whale is actually around the size of a Volkswagen Beetle (6).
Like other rorquals (members of the family Balaenopteridae), the blue whale has a long, somewhat tapered and streamlined body, with the head making up less than one-fourth of its total body length (8) (9). The rostrum (upper part of the head) is very broad and flat and almost U-shaped, with a single ridge that extends just forward of the blowhole to the tip of the snout. The body is smooth and relatively free of parasites, although a few barnacles may attach to the edge of the tail fluke, the tips of the flippers and to the small, triangular dorsal fin. There is a row of 300 to 400 black baleen plates on each side of the mouth, and approximately 90 throat grooves extend to the navel (6), which allows the throat to expand enormously during feeding (6) (7).
The blow (or spout) of this species is the biggest amongst all whales, the slender upright column of air rising up to nine meters (10). Blue whales in the Northern Hemisphere are generally smaller than those in the Southern Ocean. The female may be up to 10 metres longer than the male (6) (11).
Despite its common name, the blue whale is actually grayish-blue, with a mottled effect that is visible in some lights and can allow individuals to be identified. The underside often has a yellowish tinge, especially on whales living in polar waters, which is caused by microscopic algae called ‘diatoms’ and led to early whalers giving this species the nickname ‘sulphur bottom whale’ (6) (10).
- Also known as
- Antarctic blue whale, great northern rorqual, North Atlantic blue whale, North Pacific blue whale, pygmy blue whale, Sibbald's rorqual, southern blue whale, sulphur bottom whale, sulphur-bottom whale.
- Baleine Bleue, Baleine D'Ostende, Baleinoptère Bleue, Rorqual À Ventre Cannelé, Rorqual Bleu, Rorqual De Sibbold.
- Ballena Azul, Rorcual Azul. Top
BBC Wildlife Finder:
EDGE of Existence:
The Whale and Dolphin Conservation Society (WDCS):
- Simple plants that lack roots, stems and leaves but contain the green pigment chlorophyll. Most occur in marine and freshwater habitats.
- In some whales, the comb-like fibrous plates hanging from the upper jaw that are used to sieve food from sea water. These are often referred to as whalebone.
- Cetaceans are a group comprising all whale species, therefore including dolphins and porpoises.
- Active during the day
- Dorsal fin
- The unpaired fin found on the back of the body of fish, or the raised structure on the back of most cetaceans.
- A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.
IUCN Red List (March, 2011)
- WDCS (2002) Pers. comm.
- Macdonald, D. (2001) The New Encyclopaedia of Mammals. Oxford University Press, Oxford.
CITES (March, 2011)
Convention on Migratory Species (March, 2011)
WWF - Blue whale (March, 2011)
EDGE of Existence - Blue whale (March, 2011)
American Cetacean Society - Blue whale (March, 2011)
MarineBio - Blue whale (March, 2011)
- Carwardine, M., Hoyt, E., Fordyce, R.E. and and Gill, P. (1998) Whales and Dolphins. Harper Collins Publishers, London.
NOAA Fisheries Office of Protected Resources - Blue whale (March, 2011)
Australian Government: Department of Sustainability, Environment, Water, Population and Communities - Blue whale (March, 2011)
Sears, R. and Calambokidis, J. (2002) COSEWIC assessment and update status report on the Blue Whale Balaenoptera musculus in Canada. Committee on the Status of Endangered Wildlife in Canada, Ottawa. Available at:
- view the contents of, and Material on, the website;
- download and retain copies of the Material on their personal systems in digital form in low resolution for their own personal use;
- teachers, lecturers and students may incorporate the Material in their educational material (including, but not limited to, their lesson plans, presentations, worksheets and projects) in hard copy and digital format for use within a registered educational establishment, provided that the integrity of the Material is maintained and that copyright ownership and authorship is appropriately acknowledged by the End User.
Blue whale biology
The blue whale usually occurs alone or in groups of two or three, but occasionally large groups of up to 60 may form in areas of high food abundance. It feeds mainly on shrimp-like krill, which are filtered through the baleen plates (1). During feeding, large volumes of water and food can be taken into the mouth because the pleated grooves in the throat expand. As the mouth closes, water is expelled through the baleen plates, which trap the food on the inside to be swallowed (8). During the summer feeding season, the blue whale gorges itself, consuming an astounding 4 tonnes or more each day, meaning it may eat up to 40 million krill a day (8).
The blue whale reaches sexual maturity at 7 to 10 years of age, when it will mate with several partners during winter and early spring. A single calf is produced after a gestation period of 10 to 11 months and weaned at the summer feeding grounds, when it is approximately seven months old (12). During the nursing period, the calf consumes around 100 gallons of the mother’s fat rich-milk and grows an incredible one and a half inches in length each day, with a weight gain of 90 kilograms per day (8). The inter-birth period for female blue whales is probably two to three years, although this may have decreased recently in response to the low population densities (10).
The blue whale produces louder calls than any other animal on earth. Communication occurs via a variety of low frequency sounds and clicks. The male blue whale is capable of producing particularly long calls, which have been well studied and appear to have functions in sensing the environment, prey detection, communication and male display (13).Top
Blue whale range
The blue whale is found in every ocean except the Arctic, with a range that extends from the periphery of drift-ice in polar seas to the tropics, although it is absent from some seas such as the Mediterranean, Okhotsk and Bering (1). It follows a seasonal migration pattern between summering and wintering areas, although some individuals may remain in certain areas year-round (11). The species’ range can be loosely organised into three main populations: one in the North Atlantic (Balaenoptera musculus musculus), one in the North Pacific (Balaenoptera musculus musculus), and another in the southern Hemisphere (Balaenoptera musculus intermedia and Balaenoptera musculus brevicauda) (1).
In the Antarctic region, which formerly supported the largest blue whale population, the blue whale occurs from the Antarctic Polar Front up to and into the ice in the summer, and is thought to migrate equator-wards before winter. The pygmy blue whale is most abundant on the Madagascar plateau in the southern Indian Ocean, and off south and western Australia (1).
In the North Atlantic the summer distribution of the blue whale extends from the Scotian Shelf to the Davis Strait in Canada, eastwards to Iceland, the Denmark Strait and Svalbard, and north to the ice edge. The winter distribution of the blue whale in the North Atlantic is poorly known, but it is thought that in the past the blue whale was widely distributed in the southern half of the North Atlantic in the winter (1).
The blue whale occurs in the eastern Pacific from southern Chile to Costa Rica, where it is present year-round. In the North Pacific, it is found from the coast of Oregon to the Kurile Islands and north to the Aleutian Islands. In the past the blue whale was regularly caught off southern Japan and the Korean peninsula, but it has not been seen there in recent years (1).Top
Blue whale habitat
The blue whale inhabits the open ocean, where it is found most frequently along the continental shelf edge and near polar ice (3). It feeds at both the surface and at depth, undertaking diurnal vertical migrations as it follows its krill prey to depths of at least 100 metres (1).
Poleward movements in the spring allow the blue whale to take advantage of high prey abundances in the summer, while movement towards the subtropics in the autumn allows the blue whale to reduce its energy expenditure while fasting, avoid ice entrapment and breed in warmer waters (1).Top
Blue whale status
Subspecies: Antarctic blue whale, Balaenoptera musculus intermedia, is classified as Critically Endangered (CR); and the pygmy blue whale, Balaenoptera musculus brevicauda, is classified as Data Deficient (DD) (1).Top
Blue whale threats
Because of its enormous size and speed, the blue whale was largely safe from early whalers, who could not pursue it in open boats with hand harpoons. However, the advent of the exploding harpoon gun in 1868 allowed for the commercial exploitation of this species, with the whaling industry particularly focusing on the blue whale after 1900 (9). The slaughter peaked in 1931, when over 29,000 were killed in one season (8). After that, blue whales became so scarce that the whalers turned to other species. More than 360,000 blue whales were taken by whaling fleets in the Southern Hemisphere from 1904 to 1967 (7), and the Antarctic and North Atlantic populations were probably depleted to the low hundreds by the time whaling ceased (1). The total global blue whale population has declined by at least 70 percent, and possibly as much as 90 percent, over the last three generations, with the formerly very large Antarctic population declining over the same period by as much as 97 percent (1).
Although commercial whaling of the blue whale is now banned, its population is so small that any further mortalities may severely impact on the survival of the species. It is still subject to a number of threats including ship strikes, noise and chemical pollution, and net entanglement. The remote distribution of some blue whale populations probably makes them less vulnerable to human impacts than some other cetacean species, but local populations that inhabit waters with significant levels of human activity, such as the Gulf of St. Lawrence, may be particularly vulnerable to these threats (1).Top
Blue whale conservation
Hunting of the blue whale was banned in 1966, although some illegal soviet whaling persisted for several years after. No blue whales have been deliberately caught since 1978 (1). However, this protection almost came too late for the blue whale, and recovery has been extremely slow. Only in the last few years have there been signs that numbers may be increasing (9).
Today, there are an estimated 10,000 to 25,000 blue whales surviving worldwide, which represents around 2 to 11 percent of the total pre-commercial exploitation population (1). All international trade in the blue whale is further prohibited by its listing on Appendix I of the Convention on International Trade in Endangered Species (CITES) and on Appendix I of the Convention on Migratory Species (CMS or the Bonn Convention) (4) (5).
The blue whale occurs in a number of Marine Protected Areas throughout its range that are aimed at protecting the whole marine ecosystem, as well as whale sanctuaries in the Antarctic, Indian and Southern Oceans. Several countries have also implemented research and conservation programmes for this species, much of which is coordinated by the International Whaling Commission, and these include identifying areas of critical habitat, investigating species abundance and distribution, and mitigating the threats to the species (7).Top
Find out more
For further information on the blue whale, see:
This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
More »Related species
Play the Team WILD game
This species is featured in:
This species is affected by global climate
change. To learn about climate change
and the species that are affected,
visit our climate change pages.
MyARKive offers the scrapbook feature to signed-up members, allowing you to organize your favourite ARKive images and videos and share them with friends.
Terms and Conditions of Use of Materials
Copyright in this website and materials contained on this website (Material) belongs to Wildscreen or its licensors.
Visitors to this website (End Users) are entitled to:
End Users shall not copy or otherwise extract, alter or manipulate Material other than as permitted in these Terms and Conditions of Use of Materials.
Additional use of flagged material
Green flagged material
Certain Material on this website (Licence 4 Material) displays a green flag next to the Material and is available for not-for-profit conservation or educational use. This material may be used by End Users, who are individuals or organisations that are in our opinion not-for-profit, for their not-for-profit conservation or not-for-profit educational purposes. Low resolution, watermarked images may be copied from this website by such End Users for such purposes. If you require high resolution or non-watermarked versions of the Material, please contact Wildscreen with details of your proposed use.
Creative commons material
Certain Material on this website has been licensed to Wildscreen under a Creative Commons Licence. These images are clearly marked with the Creative Commons buttons and may be used by End Users only in the way allowed by the specific Creative Commons Licence under which they have been submitted. Please see http://creativecommons.org for details.
Any other use
Please contact the copyright owners directly (copyright and contact details are shown for each media item) to negotiate terms and conditions for any use of Material other than those expressly permitted above. Please note that many of the contributors to ARKive are commercial operators and may request a fee for such use.
Save as permitted above, no person or organisation is permitted to incorporate any copyright material from this website into any other work or publication in any format (this includes but is not limited to: websites, Apps, CDs, DVDs, intranets, extranets, signage, digital communications or on printed materials for external or other distribution). Use of the Material for promotional, administrative or for-profit purposes is not permitted.