Endangered
Blue whale
Balaenoptera musculus
Blue whale is a mammal in the family Balaenopteridae (order Cetacea) — Balaenoptera musculus, recorded as Endangered.
Appearance
The blue whale is a slender-bodied cetacean with a broad U-shaped head. Thin, elongated flippers; a small sickle-shaped dorsal fin located close to the tail, and a large tail stock at the root of the wide and thin flukes. The skin has a mottled grayish-blue coloration, appearing blue underwater. The mottling patterns near the dorsal fin vary between individuals.
The upper jaw is lined with 70–400 black baleen plates less than 1 m (3.3 ft) in length. Reaching a maximum confirmed length of 29.9–30.5 m (98–100 ft) and weighing up to 190–200 t (190–200 long tons. 210–220 short tons), it is the largest animal known to have ever existed.
Published measurements include length about 27.1.
Range and habitat
Four subspecies are recognized: B. M. Musculus in the North Atlantic and North Pacific, B. M. Intermedia in the Southern Ocean, B. M. Brevicauda (the pygmy blue whale) in the Indian Ocean and South Pacific Ocean, and B. M. Indica in the Northern Indian Ocean. The blue whale was abundant in nearly all the Earth's oceans until the end of the 19th century. Blue whales continue to face numerous man-made threats such as ship strikes, pollution, ocean noise, and climate change.
Pins are Wikidata “endemic to” fields. Orange dots, when present, are GBIF occurrence tiles — survey bias included.
Diet and breeding
Each year, a light and dark layer of wax is laid corresponding with fasting during migration and feeding time. The blue whale is usually solitary, but can be found in pairs.
Populations may go on long migrations, traveling to their summer feeding grounds towards the poles and then heading to their winter breeding grounds in more equatorial waters. There is evidence of alternative strategies, such as year-round residency, and partial (where only some individuals migrate) or age/sex-based migration. Little is known about mating behavior, or breeding and birthing areas.
In crisis
There is a population in the waters off Chile that may constitute a fifth subspecies. In general, blue whale populations migrate between their summer feeding areas near the poles and their winter breeding grounds near the tropics. It was hunted almost to the point of extinction by whalers until the International Whaling Commission banned all blue whale hunting in 1966.
The International Union for Conservation of Nature has listed blue whales as endangered as of 2018. The global blue whale population is estimated to be 5,000–15,000 mature individuals and 10,000–25,000 total as of 2015–2018.
CITES lists this taxon on Appendix I. Confirm the current appendix on the CITES checklist.
Blue whale is Endangered on this catalog because that is the IUCN category stored on Wikidata. Confirm the official criteria and any later count on iucnredlist.org.
Sources
Written for this catalog from the English Wikipedia article on Blue whale, Wikidata item Q42196. Family and order context is original field-guide writing about the group, not a copied assessment of this one species. Wikipedia text is CC BY-SA. Not an IUCN assessment. Counts, when quoted, can change — confirm them on the recovery programme and on iucnredlist.org.
