What is a jellyfish?

Steven Haddock of the Monterey Bay Aquarium Research Institute (let's all pause a moment to reflect on kismet of that surname/job combination) made this video about the wide world of creatures that we call "jellyfish." It's a great summary of the extreme diversity encompassed under one, catch-all name, and does a really nice job of explaining relationships between different species and families of jelly-like creatures.

And let's not discount the stop-and-gawk value. Check out 1:27 for a Hydromedusae that looks strikingly like Darth Vader's helmet. You'll also meet shell-less snails, jelly worms of the sort you don't find at the candy store, and even colony-dwelling creatures thousands of individuals strong.

Video Link



  1. I love jellyfish. The bio-luminescent ones look like something out of a rather delightful hallucination.

  2. “[Jellyfish] are 97% water or something, so how much are they doing? Just give them another 3% and make them water. ”

    -Karl Pilkington

  3. I LOVE deep sea stuff. There is a great book out there called The Deep that features a lot of these guys.

  4. It makes you wonder how old sea life really is, as soft bodies like these are near impossible to preserve (though there are some around.)

    The Burgess shale fossils have some true aliens preserved. I can only imagine the crazy soft bodied beasts from long ago.

    If I had an armored sub time machine, I’d visit the Precambrian/Cambrian ocean. I imagine it would be scary and as alien as all get out.

      1. While not the most exciting of the creatures of that time, trilobites are and always will be my favorite.

          1. That would be slick. Or cuff links…. not that I have ever worn them except for prom and my wedding. Baltic amber would be cool too. I have some nice pieces of that – the perk of having a Polish MiL.

    1. In truth, there are enough chances that it really looks like macroscopic animals aren’t much older than that. But the first ones, the Vendian fossils, are certainly as mysterious and beautiful as anything you might hope to find.

  5. The fact that they just may be immortal is reason enough to be in awe of these wonderful brainless creatures.

    I have a brain and I will die vs. no brain and I’ll live forever. Which do I choose?

    1. I have a brain and I will die vs. no brain and I’ll live forever. Which do I choose?

      Jellyfish have no internet connection. Or higher brain functions. So they can’t ask the question.

      The real question is:

      Would you rather have a brain and die of old age, or be so fragile and defenseless that the only way your genes can ensure their survival is by not programming you cells to die?

  6. Haddock? Like he had a dock, for like fishing and boats and stuff and that was the only reason he got hooked on fish-ish things?

  7. Billions of bilious blue blistering barnacles! Does this Haddock fellow hang out with a young English journalist who owns a white terrier?

    1. Seconded. What I love is the siphonophores, I think Physophora hydrostatica has it all over on hallucinogenia. What I really like is that most of them are so loosely aggregated that they can’t even be observed outside of the deep sea.

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