Walking shark on sea floor

  1. http://phys.org/news/2013-08-shark-indonesia.html


    There's a video included in the second link.
  2. jcsd
  3. Borek

    Staff: Mentor

    Strange, looks pretty clumsy.
  4. It is clumpsy , atleast it does not use limbs rather fins to acheive the goal. Its quiet interesting to see fins used the same way (movement) certain lizards use their legs.
  5. Pythagorean

    Pythagorean 4,483
    Gold Member

    I find this interesting because the evolution of limbs would require a neural control system that knew how to use them appropriately, and here we see an example of a neural control system ready and waiting for the morphology. As thorium says, the motion does look similar to some species of amphibian/reptilian gait.
  6. Borek

    Staff: Mentor

    I see your point, and I agree it is interesting.

    Still, it looks clumsy and I don't see in what way it is beneficial (obviously somehow it is).
  7. Pythagorean

    Pythagorean 4,483
    Gold Member

    Me either, but it doesn't need to be beneficial; it could just be a spandrel. Or is there evidence that it was selected for?
  8. Question is why would it need to be beneficial? Too long it has been drilled into our heads that many traits have to be beneficial to survive in our environment. Maybe this trait was just an accident or has little benefit to the organism or it rarely uses this trait, we do not know. There are many areas in the field of biology, that does not make sense. It is our ingrained sense to see usefulness in a particular thing, probably biases our understanding of traits and survival of organism.
  9. Borek

    Staff: Mentor

    Perhaps you are right - it doesn't have to be beneficial.

    My line of thinking was that there are at least several species of sharks living and feeding on the bottom, and I have never heard about any of them behaving this way - as far as I know, they all swim (compare - there is both a walking bamboo shark and a swimming houndshark). For me that suggests bamboo sharks behave this way for a reason. It is not clear to me how close to the surface they live - would they feed in the intertidal zone (breakers, strong currents), these fins would make a great sucker to keep the fish safe on the bottom, and then the motion could be a spandrel as Pythagorean suggested. But I am under impression they live slightly deeper, where swimming is enough. Another explanation could be that they do use fins as sucker as part of their feeding strategy - say to create a stable base for pulling food from between the rocks.

    But now I am speculating and I should ban myself.
    Last edited by a moderator: Sep 25, 2014
  10. Curious3141

    Curious3141 2,943
    Homework Helper

    It is really cute!

    Sorry if that wasn't a scientific comment. :biggrin:
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