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Is an orca (killer whale) a whale or a dolphin?

Image taken from an unmanned hexacopter at >100ft during a research collaboration between NOAA/SWFSC, SR3 and the Coastal Ocean Research Institute. Research authorized by NMFS permit #19091.
Image taken from an unmanned hexacopter at >100ft during a research collaboration between NOAA/SWFSC, SR3 and the Coastal Ocean Research Institute. Research authorized by NMFS permit #19091.

It’s one of the hottest topics we see discussed online, so please geek out about whales with us for a minute as we dive into the answer: what IS an orca? A whale? A dolphin? The answer may surprise you!

Think back to high school science and the idea of Taxonomy: arranging all living organisms on Earth into different groups. Plants, animals, fungi, bacteria, etc. Those categories are further divided based on traits, genes, and specific features (you may also remember one of the fun acronyms to remember these groups!).

It’s a big family tree for all life on Earth. We group similar things together - Humans are animals because we share traits with other animals. Flowers are plants because they’re similar to other plants! But not all animals are humans, and not all plants are flowers.

Northern Resident orca, Fife, swimming at the surface

By adopting an orca, you directly support WDC's work to protect them.

Keeping that in mind, ALL whales, dolphins, and porpoises are part of the animal group known as Cetacea, or cetaceans (derived from the Ancient Greek word for “sea monster” - but that’s a blog for another day). Cetaceans are split into two groups: whales who have teeth (toothed whales) and whales who don’t (baleen whales)! Those categories are even further divided into families based on specific shared traits.

Whale Taxonomy chart

The category of toothed whales is broken down into 5 families –

  1. Narwhals & belugas
  2. Sperm whales
  3. Beaked whales
  4. Dolphins
  5. Porpoises

The Dolphin family share other traits that both define dolphins and separate them from other toothed whales.

So, all dolphins are whales (it’s true!) but not all whales are dolphins! Can you see where we’re going with this?

Orcas are the largest species in the dolphin family. Because of their size and because they are also called 'killer whales', they’re sometimes called whales. Other people call them dolphins. Both are right, and it all depends how specific someone is in their classification.

So is an orca a whale or a dolphin? They’re both! They’re also one of our favorite marine mammals, and one we’re working hard to protect them, with much of our work focusing on saving the Southern Resident orcas.

Now the next time you’re caught up in an online debate over “orca: whale or dolphin?” you can say with authority: YES!

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2 Comments

  1. Dennis Weiler on 02/26/2022 at 6:09 pm

    Yes! My favorite response to an either/or question.

  2. June Craner on 03/09/2022 at 12:27 pm

    Wonderful explanation. Thank You!

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