• Question: I saw a picture of an Osedax worm who are said to feed on the remaining bones of a dead whale, are they dangerous? And if they don't have a stomach or a mouth how do they absorb the nutrients from the bones?

    Asked by directioner1309 to Allan, Angela, Diva, Harriet, Nathan on 29 Jun 2012.
    • Photo: Allan Pang

      Allan Pang answered on 29 Jun 2012:

      Yes. Osedax worms do not have mouth or stomach.

      This is a picture of an Osedax anatomy:

      You can see that they have the bright red palps on the surface, which acts as gills for collecting oxygen from seawater. Then a trunk (or tube) containing tiny osedax MALE worms (yes, male worms living in female worms), then the tube is attached to bones of whales.

      In the bone, the worms have ovary, as well as “roots”, which have symbiotic bacteria; the bacteria basically plays the role of breaking down the oils and proteins of the whale bone to provide food for the worm.

      So, they don’t really need stomach or mouth, because the bacteria are doing the job for them!

    • Photo: Diva Amon

      Diva Amon answered on 5 Jul 2012:

      Hey directioner1309,

      Sorry for taking so long to answer your question. I’m so impressed that you know so much about Osedax. These are one of the deep-sea animal groups that I specialise in.

      Don’t worry, Osedax worms aren’t dangerous and doesn’t harm the whales as it only colonises the whale bones way after death.

      These animals were only discovered in 2004 and so we still know very little about them, especially about their nutrition. We do know that they use a large root-like structure to burrow down into the bones so that they can feed. It was recently discovered that they have enzymes in this root structure which secrete acids which break down the bone. Scientists had long thought this was how it was done as Osedax do not have any hard structures that could be used for digging. Here is an article on that:
      http://www.bbc.co.uk/nature/18594493

      The roots also contain symbiotic bacteria. Allan’s answer and the BBC article above weren’t exactly right. We know that Osedax breakdown the collagen (a type of protein) in the bones to get their food from using enzymes, not the fats and oils. the broken down food is then absorbed straight into the blood stream so there is no need for a mouth or tummy. We aren’t quite sure what the exact role of the symbiotic bacteria are however.

      Allan was right about the tiny males living on the females. One female can have as much as one hundred males living on and in her tube.

      The most exciting thing to me about these worms, is how in such a big ocean do they find the bones of a whale to live on! One of the mysteries we are trying to solve.

      Since I’ve started my PhD, I’ve discovered three new species of Osedax worm. They were found on two whale skeletons in the Antarctic deep sea. I don’t have names for them yet so if you have any good ones, let me know!

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