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How Do Whales Breathe?


Because whales live in the ocean, many people think they are fish. But do you know that whales and dolphins are not fish? They are mammals. People are mammals too. Mammals are the group of animals that breath air using lungs, give birth to live young (rather than laying eggs), and feed their young with mother’s milk. All animals, including people, need oxygen, a chemical found in the air and in water. Fish use their gills to take oxygen from the water that they live in. But people get the oxygen we need by breathing air, using our lungs. Whales and dolphins use their lungs to breathe air also.

That’s one reasons why they come to the surface of the ocean. Sometimes they lie right at the surface of the water, with just a part of their back sticking out. Look closely at a picture of a whale or dolphin; can you see a nose on the whale? You can’t, because whales don’t have noses like you and me. Instead they have a hole – called a “blow hole” – on top of their heads. Sometimes when a whale breathes air out of its blow hole, it shows up as a spray or mist – called a “spout” – that can be seen many miles away. Blow holes are surrounded by muscles that keep the hole closed when the whale or dolphin is under water and open it when the animal is at the surface and needs to breathe.

In fact, some of the animals have two blow holes next to each other and others have only one. So when you see a picture of a whale, see if you can tell the difference. Pilot whales and dolphins have one blow hole; humpbacks, minkes and right whales have two.


  1. Hi Aaron.
    Whales have two lungs, like we do. The total capacity of the blue whale’s lungs is 5,000 liters, or about 1,300 gallons. I must confess, I don’t know much about Limo size! 🙂 However, a brief web search suggests the lungs of the humpback whale are about the size of a compact car. Hope this answers your question!

  2. Hi Kathy. Do you have any information of the size and capacity of a humpback’s lungs? Do they have a single lung or 2 like humans? While on a whale watching tour, I was told they have a lung the size of a limo, but that seems incorrect compared to pictures I have seen. You mentioned the blue whale had a capacity of 5000 liters, is that close to limo size?

  3. Hi Anwesha.
    Like humans and other mammals, lungs are the main respiratory organs of whales and dolphins. Here’s a great post from Whale and Dolphin Conservation that explains more about how whales breath.
    Thanks for your question!

  4. Hi Maria.
    Great question! You are correct that whales and dolphins are mammals. As mammals, they breath air through lungs. They have to surface to breath. When you see a whale or dolphin “spout” at the surface, they’re actually breathing. They expel air first then inhale air to fill their lungs before they dive again.
    Thanks for your comment.

  5. Is Integument the main restiratory organ of whale???

  6. As we know mammals cannot breath under water and whales and dolphins are also mammals then how they can breath inside the occean ???

  7. I thoughts whales had blowholes because they descended from land walking quadrupeds. Fish broke off from their ancestry and developed gills way before the whale ever existed. Perhaps, in time, whales and other sea mammals would develop a completely different breathing apparatus from gills or blowholes.

  8. Fish use their gills to take oxygen from the water that they live in. But people get the oxygen we need by breathing air, using our lungs. Whales and dolphins use their lungs to breathe air also. That’s one reason why they come to the surface of the ocean

  9. Thnks this information

  10. Hi Philip.
    Yes, whales have pleura. Thanks for your question!

  11. Thanks for very good information
    I was of the view that only Dolphin breathe

  12. hello ,
    i have a question relates that concerns the anatomy of the respiratory system of the whales …
    Do the Whales have Pleura surrounding the lungs ?

    thank u

  13. Thanks for your question, Joy. The dolphin’s only “nostril” is the single blowhole at the top of their head. Baleen whales have two blowholes.

  14. Even though dolphins have a single blowhole, do they have a right and left nostril or only one nostril? I’ve found conflicting information on this. Thanks

  15. Whales are mammals and must breathe air. They come to the surface to breathe. Thanks for your question!

  16. Why whales come water surface time to time . What is the reason behind it

  17. Hi Daniel.
    When a whale exhales then inhales, it exchanges about 90% of the oxygen in its lungs for fresh oxygen. When humans inhale then exhale, we exhange about 20% of the oxygen in our lungs for fresh oxygen.
    Here’s a great post from Whale and Dolphin Conservation that explains more about whales vs humans’ gas exchange during breathing, and also compares how whales and humans store oxygen.
    Thanks for your question!

  18. Thank you for the interesting article and replies, Kathy.
    What does the 90% whales / 20% humans oxygen exchange mean?
    If you talk about the lung size when breathing out, a human would have about 80% (~20% residual capacity).
    Thank you!

  19. Hi Joey.
    Here’s a great article from Scientific American that explains this “half sleep” better than I ever could!
    Thanks for your question!

  20. Im confused on the whole “whales rest half their brain at a time” can you explain to me how they do that?

  21. Hi Rose.
    Despite their large size, a whale can exhale and inhale in less than a few seconds! And, they exchange 90% of the air in their lungs when they do so! Often when they are diving more deeply, they will surface and breathe several times over the course of a few minutes before going under again for a longer dive. Thanks for your Question!

  22. Hi Kathy, thanks for the informative post. Given how huge whales are, how long do you suppose they have to stay on the surface of the water to take in enough oxygen to survive under water?

  23. thanks

  24. Hi Astaria.
    Some whales rest half their brain at a time. Another strategy scientists have found is that sometimes whales will take short naps between breaths. I would suggest this is both a physical and behavioral adaptation. Thanks for your question!

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