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How Do Whales and Dolphins Swim?


How would you describe the shape of a whale or dolphin? Wouldn’t you say they are very streamlined? Very few appendages (like your arms and legs) stick out to slow the animal down as it swims through the water. A whale’s body is shaped like a submarine, or the body of an airplane.

The smooth, rubbery skin, the lack of hair, and no ears sticking out also contribute to the sleek body designed for speed in the water.

But it takes more than a sleek body to maneuver in the water. Remember, when whales and dolphins are going after their food, they not only swim at the surface, they also dive to great depths. They need rudders and propellers.

Look closely at a whale or dolphin – you’ll see that many have a dorsal fin, the fin that sticks up from the back of the animal. Scientists believe that the dorsal fin acts as a stabilizer or a rudder. You might think that the dorsal fin has bones in it, like the fins on fish. But the whale’s dorsal fin has no bones. Instead, it is made up of dense tissue, somewhat like a ridge of thick, folded skin.

You’ll also see flippers low on the sides of the animals. Those flippers are used for steering, for balancing, and for stopping. But they are not used for moving forward through the water.

Forward motion is created by the whale’s or dolphin’s tail, or flukes, moving up and down in the water. It serves as the propeller. Powerful muscles running along the backbone and sides of the whale’s body move the tail up and down in the water, providing the power that pushes the animal through the water, or deep into the ocean. In fact, one way to remember that whales are not fish is that fish move their bodies sideways when they swim; whales move their bodies up and down.


  1. It’s interesting to know that scientists believe that the dolphins’ boneless dorsal fin acts as a stabilizer for the dolphin or a rudder. My son, who loves dolphins, would like this fact when I share it with him later. I’m planning to take him on a dolphin tour charter as a surprise soon, so I’m telling him daily dolphin fun facts to get him excited. Thanks!

  2. Can dolphins swim on their backs?

  3. Hi Lachy.
    Dolphins and whales swim with their tails making an up-and-down movement. This is different from the side-to-side tail movement that fish make. Thanks for your question!

  4. Hello, I’m wondering what motion do they swim in?

  5. Dolphin is a wonderful animal. It is a kind of mammal which lives on water. They are very attractive animal which draws so many interest of the tourist all over the world. Watching them personally gives an honor because it is very rare and very hard to find them without spending enough money. Seeing them means that you are financially capable. Unless you are lucky enough to live in a place near dolphin sanctuary haven.

  6. I never knew that there are factors that are designed to help a dolphin to swim faster in the water —rubbery skin, lack of hair, and no ears sticking out. My son is so interested in how the dolphins swim. He’s fond of watching animated series featuring dolphin shows because he’s amazed at how fast the dolphins can swim. At the moment, I’m looking to find a place that we can visit to watch different dolphin swim and probably try to swim with them too. I will make sure to save your blog for future reference.

  7. Now i whant to be a mirine sinticed.

  8. this is really a some to lean.

  9. Hi Sierra. No, they don’t make walking motions when they swim. They use their pectoral fins for steering, but the fins themselves aren’t very mobile. Thanks for your question!

  10. Since it has been found that whales have finger like bones in their fins, does that mean that the do walking motions as they swim?

  11. That’s a great question! The vertebral column actually extends into the fluke. As to why the “paddle” part of the fluke doesn’t have bones, I’m afraid I don’t know the answer. If you find out, please post here! Thanks.

  12. Why do whale flukes not have bones?

  13. Thank you for your comments, Kasha. Whales, dolphins, and porpoises all belong to the same order of mammals called cetaceans. Dolphins and porpoises are part of a suborder of whales called odontocetes, or toothed whales. Broadly speaking, dolphins and porpoises are types of whales. With respect to general shape and swimming ability, all share similar characteristics. Thanks again for your interest.

  14. Thanks for the information, but i think that the whale has nothing to do with the dolphin facts. Of course the whale moves its “Fluke” up and down, but that is not the point. This article is supposed to be about the dolphin resources compared to a fish, not the whale compared to the fish. You either need to take out some of the whale information and put dolphin information in, or you could put this article in with the whale category.

    Someone that has an actual opinion,

  15. Hi Sara.
    Thank you for your interest in dolphins! The nonprofit organization “Whale and Dolphin Conservation” has a lot of great information about these amazing animals. See:
    Good luck and best wishes!

  16. Hi i want to work at seaworld when i grouw up and i thought you could give me some info about dolphins.(that is the animal i want to work with!)

  17. Thanks for your question! No, whales do not have to stay in motion at all times. In fact, some “sleep” by resting at the surface in a behavior called “logging”. During this time, they move only enough to keep their blowholes above water to breath.

  18. Do whales have to stay in motion at all times, like sharks?

  19. I want to be a marine biologist!!! So this is very helpful for what makes me happy and iterest me!

  20. Interesting………

  21. This is helping me a lot in my work

  22. Thanks, Stephanie, for answering Susan’s question! It does indeed have to do with the evolution of dolphins as mammals.

  23. Hey Susan!

    Cetaceans move their bodies up and down through the water because they are mammals. Look at the way a dog runs. Its spine moves up and down in a fluid motion, which is the same motion a dolphin’s spine makes when it swims. Likewise, you can see how reptiles are more closely related to fish than mammals because they retain the side to side motion that originated in fish. I don’t think it has anything to do with diving as there are many fish that live at great depths.

    Hope this helps you!

  24. Can you please explain why bony fish and cetaceans have a different motion for their tail. If both are used for propulsion why do bony fish have a sideways motion and whales and dolphins use an up and down motion. Does this account for the depths these mammals can reach upon diving?
    Thank you


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