Bryan McAllister’s personal reference notebook
September 11, 2026Short & citedBlog
Civic Viewpoint.
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Field Notes • Marine Mammals

Whale

Whales are a diverse group of large marine mammals in the cetacean order, including baleen whales and toothed whales.

Updated September 11, 20261 min readCited sources

Whales are large marine mammals found in oceans worldwide, ranging from small species to the blue whale, the largest animal ever known.

What it is

Whales belong to the cetacean order, which also includes dolphins and porpoises. They are divided into two main groups: baleen whales, which filter-feed on tiny organisms like krill, and toothed whales, which hunt fish, squid, and other prey. As mammals, they breathe air through lungs, give birth to live young, and nurse their calves.

Why it matters

Whales play key roles in marine ecosystems, from cycling nutrients to supporting food webs. In Canada, they inhabit Pacific, Atlantic, and Arctic waters, making them relevant to conservation, fisheries management, and Indigenous marine knowledge. Many species face threats from whaling, ship strikes, and habitat change.

Key details

Blue whales are the largest, reaching about 30–33 metres long and up to 200 tonnes. Lifespans vary by species, with some living 80–90 years or longer. Many whales migrate seasonally between cold feeding grounds and warmer breeding areas, though some move within broad ocean ranges without regular long-distance travel.

In short

  • Whales are mammals, not fish, and breathe air.
  • Two main groups: baleen whales (filter-feeders) and toothed whales (hunters).
  • Blue whales are the largest animals ever.
  • Whales are important in Canadian waters for ecology and conservation.
Canadian angle

Whales are important to Canada’s Pacific, Atlantic, and Arctic marine environments, and several species occur in Canadian waters, making them relevant to conservation, fisheries management, and Indigenous marine knowledge.

Quick questions

How big is a blue whale?
Blue whales can reach about 30–33 metres long and weigh up to about 200 tonnes.
What do whales eat?
Baleen whales eat krill and tiny prey; toothed whales eat fish, squid, and other marine animals.
Are whales mammals?
Yes. They breathe air, give birth to live young, and nurse their calves with milk.

Sources

  1. National Geographichttps://www.nationalgeographic.com/animals/mammals/facts/blue-whale
    Supports: Blue whales are mammals, their size, diet, lifespan, and migration behavior.
  2. NOAA Fisherieshttps://www.fisheries.noaa.gov/species/blue-whale
    Supports: Blue whale size, krill diet, lifespan estimate, and general distribution.
  3. Monterey Bay Aquariumhttps://www.montereybayaquarium.org/animals-the-ocean/animals-a-to-z/blue-whale
    Supports: Blue whale maximum length and weight.
  4. The Marine Mammal Centerhttps://www.marinemammalcenter.org/animal-care/learn-about-marine-mammals/cetaceans/blue-whale
    Supports: Blue whale diet, lifespan estimate, and migration to warmer waters.
  5. Encyclopaedia Britannicahttps://www.britannica.com/animal/blue-whale
    Supports: Blue whale classification as a baleen whale and its extreme size.