Bryan McAllister’s personal reference notebook
September 11, 2026Short & citedBlog
Civic Viewpoint.
A quiet encyclopedia with a personal desk
Kept by Bryan McAllister — short guides, clear facts, and the Canadian angle when it matters.
Field Notes • Biology

Blue whale

The blue whale (*Balaenoptera musculus*) is the largest animal known to have ever lived and the largest living marine mammal.

Updated September 11, 20261 min readCited sources

The blue whale is the largest animal ever known to have lived, a baleen whale that feeds on krill and is found in oceans worldwide except the Arctic Ocean.

What it is

The blue whale (*Balaenoptera musculus*) is a rorqual whale in the family Balaenopteridae. It is the largest living marine mammal, with confirmed lengths of about 30 metres and weights up to 200 tonnes. Blue whales use baleen plates to filter-feed, primarily on krill.

Why it matters

Blue whales are an endangered species, heavily reduced by 20th-century commercial whaling. They face ongoing threats from vessel strikes and entanglement in fishing gear. In Canadian waters, they occur in the North Atlantic and North Pacific, making them a focus of marine conservation and whale-watching.

Key details

Blue whales live about 80 to 90 years and migrate between feeding and breeding grounds. They can consume several tonnes of krill per day during feeding periods. Their conservation status remains endangered, with protection efforts ongoing.

In short

  • Largest animal ever known to exist
  • Endangered baleen whale that feeds on krill
  • Found in all oceans except the Arctic
  • Lives about 80–90 years
Canadian angle

Blue whales occur in Canadian waters, including the North Atlantic and North Pacific, making them relevant to Canadian marine conservation and whale-watching interests.

Quick questions

How big is a blue whale?
Blue whales can reach about 29.9–30.5 m (98–100 ft) in confirmed records, with some reports up to about 33 m (110 ft).
What do blue whales eat?
Blue whales eat almost exclusively krill, which they filter from seawater using baleen plates.
Are blue whales endangered?
Yes. Blue whales are listed as endangered.

Sources

  1. Wikipedia — https://en.wikipedia.org/wiki/Blue_whale
    Supports: Scientific name, maximum length and weight, classification as largest animal, average adult weight
  2. Britannica — https://www.britannica.com/animal/blue-whale
    Supports: Maximum length, approximate weight, largest accurately measured individual
  3. NOAA Fisheries — https://www.fisheries.noaa.gov/species/blue-whale
    Supports: Diet, habitat, lifespan, conservation status, threats, size and weight ranges
  4. New Bedford Whaling Museum — https://www.whalingmuseum.org/research/research-resources/whale-science/biology/about-whales/species-of-local-interest/blue-whale/
    Supports: Adult size, weight, range, diet, population status
  5. The Marine Mammal Center — https://www.marinemammalcenter.org/animal-care/learn-about-marine-mammals/cetaceans/blue-whale
    Supports: Size, lifespan estimate, endangered status, diet
  6. National Geographic — https://www.nationalgeographic.com/animals/mammals/facts/blue-whale
    Supports: Size, weight, endangered status