Whales Had Legs Until 40 Million Years Ago, Fossils Show

By Eliza Strickland | September 12, 2008 9:47 am

whale legsA new fossil study has pinpointed the moment when whales lost their distinct legs and tail and developed flukes, sometimes called tail fins, instead: Flukes are the two wide, flat triangular lobes on a whale’s back end and are made of skin and connective tissue, with bones in the middle [National Geographic News]. Researchers say that the Georgiacetus vogtlensis, whose fossil was found in Alabama, was one of the last whales to have powerful back legs and a tail like a dog’s, and that whales evolved flukes between 40 and 38 million years ago.

Paleontologists already knew that the ancestors of whales once strode on land on four legs, just as other mammals do. Over time, as they evolved to dwell in water, their front legs became flippers while they lost their back legs and hips, although modern whales all still retain traces of pelvises, and occasionally throwbacks are born with vestiges of hind limbs [LiveScience].

In the new study, published in the Journal of Vertebrate Paleontology [not yet online], researcher Mark Uhen examined the vertebrae of the Georgiacetus, a sharp-toothed whale that cruised the Gulf of Mexico about 40 million years ago. After analyzing the fossils for almost three years, Uhen concluded the individual had a tail, but no fluke, and that Georgiacetus wiggled its hips and moved its entire trunk up and down through the water to move forward—a swim stroke whales no longer use [National Geographic News].

The first whales known to possess flukes are close relatives of Georgiacetus that date back to 38 million years ago [LiveScience]. This suggests that in those two million years, whales developed flukes and took the final step in their transition from land to sea.

Check out pictures of the fossils that link whales to their closest living relatives–hippos–in the DISCOVER article, “All in the Whale Family.”

Image: Mary Parrish/Smithsonian Institution

MORE ABOUT: evolution, ocean, whales
  • Arthur Walker

    Still confused. Did Whales evolve from hofed animals or land carnivours?
    Has any one come up with an evolutionary tree?
    Artie Walker

  • http://yahoo.com Ashlee McLean

    How do you know your research is correct?

  • Austin

    The dumbest article I have ever seen. Those evolved flukes are use in reproduction. 50 positive no leathal mutations would need to take place. This is not science.

  • Austin

    The dumbest article I have ever seen. Those evolved flukes are use in reproduction. 50 positive non leathal mutations would need to take place. This is not science.

  • http://blogs.discovermagazine.com/80beats/ Eliza Strickland

    @ Arthur Walker: Wikipedia actually has a really good page on whale evolution. While their whole family tree hasn’t been definitively settled on, researchers think that whales evolved from hoofed animals. And they believe that the earliest hoofed mammals were at least partly carnivorous or scavengers, because of the sharp, pointy teeth found in their fossils.

    @ Ashlee: Not sure what you’re asking. I’m simply reporting on the research done by these paleontologists, which was published in a peer-reviewed journal.

    @ Austin: Not sure what you’re on about, either. It’s quite clear that whales evolved from land mammals that had back legs and a slender tail. Maybe there’s some confusion regarding the word “flukes,” which researchers use to describe the two lobes that make up what is commonly thought of as the tail of a modern whale.

  • kelsey

    HAHAHAHAAHAHAHA, wikipedia is your source?
    that website is is not legit.

  • http://blogs.discovermagazine.com/80beats/2008/09/12/researchers-determine-when-whales-legs-turned-into-a-tail/ Ashlee

    Austin just because you read something doesn’t always mean it’s true, i know that, but if you really believe in it who has the right to say it’s false?

  • Ashlee McLean

    Austin you always talk about if the research is correct. No one may know if my research is true, but just know that science doesn’t ezplain everything. Can science explain why whales sing… okay maybe it can, but can science explain what whales sing about. No, I don’t think so.

  • Ashlee

    Ummm, Ashlee you don’t spell explain with a z.

  • David

    kelsey: The author did not say that Wikipedia was her source, she said, in response to a question, that it has a really good page on whale evolution, which is true. Except for a few sites that people habitually vandalize, Wikipedia is quite accurate, especially in scientific matters, at least as accurate as Encyclopedia Britannica (see “Internet encyclopaedias go head to head” Nature, 15 December 2005). Of course, to be sure, you should always check the primary peer-reviewed literature, but many people don’t have the time, motivation, or reading ability to do that.

    ashlee: > Austin just because you read something doesn’t always mean it’s true, i know that, but if you really believe in it who has the right to say it’s false?

    a person who has evidence that contradicts the claim. Science isn’t “feelings,” it’s evidence that supports or contradicts hypotheses.

    > The dumbest article I have ever seen. Those evolved flukes are use in reproduction. 50 positive no leathal mutations would need to take place.

    Interesting claim. Can you point to any peer-reviewed research article that supports it?

    > This is not science.

    Unless you can, it certainly isn’t.

    Why do people who can’t even spell or frame a coherent sentence think they are experts on evolutionary biology?


  • Ashlee McLean

    Just because some people can’t spell or frame a coherent sentence, as you so correctly state, doesn’t mean that these people don’t have ideas or feelings. Just because people don’t talk the same as you, that doesn’t mean that you two don’t agree on the same thing, so watch what you say about people.

  • Kelsey

    Haha you just got told.

  • Korbin

    OK, so, we’ve gotten off the topic at hand; we were once having an intelligent discussion on whether or not this article is legitimate, and now we’re just arguing semantics. And toward whether or not Wikipedia is an accurate source: http://en.wikipedia.org/wiki/Wikipedia:Bots. There are bots, it you are too lazy to read the page, to correct errors in Wikipedia, and there are literally thousands of people, usually experts on the subjects, looking for errors on pages simply for fun. Therefore, Wikipedia is one of the most accurate sources you can find. Think about it, if it wasn’t accurate, would it have prospered as it has? Finally, toward the coherent sentence conversation; if someone can’t even “spell or frame a coherent sentence” then they have no reason to take part in an intelligent discussion, in which they slam the author.

    Good Day

    Korbin “El Jefe, The Maverick, Vice Presidente Del Luna” McCoy

  • Korbin “El Jefe, The Maverick, Vice Presidente Del Luna” McCoy

    Oh, and whales totally had legs.

  • Ashlee McLean

    The same thing I told Austin, Im going to tell you. PEOPLE ARE MORE INTELLIGENT THAN YOU GIVE THEM CREDIT FOR!!!!! Most of the people in America are being put down everyday and I’m sick and tired of it. Korbin if you want people to listen to what you have to say, listen to what they have to say. Don’t go and put people down because of their academic level. Im tired of ignorant people like you voicing your opinion, and instead of sticking to the facts, you go and slam other people, YOU INCONSIDERATE LITTLE…. don’t talk about other people, because you’ll end up getting hurt.

  • Bailey

    Actually whales evolved from a wolf-like carnivorous creature that preyed on dead fish near the shores eventually went into the water developed webbed claws then developed a fluke and turned into the whales we know today

  • selena

    nice picks

  • Beatriz

    Funny, they claim whales had legs but have never found a fossil record of a whale showing this.

  • jen

    Evolutionists believe that whales have leftover vestigial pelvises that indicate they evolved from another type of creature. However, even assuming that the evolutionists were correct about this, this would mean that at some point the hypothetical land mammal would not have been able to survive on land or in water. In order for an animal, such as a dog, to evolve into a whale, it would need to get rid of its pelvis. This means that, at some point, the creature wouldn’t have a tail suitable for aquatic life, and wouldn’t have legs suitable for living on land. It would be handicapped in the wild and would be extremely vulnerable to predators. Whales had legs at one time ? total BS


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