Bipedal locomotion of Octopus bimaculoides

Discussion in 'Behavior and Intelligence' started by Stavros, Oct 5, 2009.

  1. Stavros

    Stavros GPO Registered

    Joined:
    Jun 26, 2008
    Messages:
    165
    Likes Received:
    35
    Location:
    American University of Kuwait
  2. ckeiser

    ckeiser GPO Supporter

    Joined:
    Oct 16, 2008
    Messages:
    120
    Likes Received:
    1
    I've wondered if octopus that exhibit this mode of locomotion always use the same two arms to "walk". I know that certain species, or at least individuals, show arm preferences for tasks.
     
  3. DWhatley

    DWhatley Cthulhu Staff Member Moderator

    Joined:
    Sep 4, 2006
    Messages:
    19,078
    Likes Received:
    1,123
    Location:
    Gainesville, GA USA
    I would say it is more than just a "preference" since many have different length and thickness to specific arms as a species.
     
  4. CaptFish

    CaptFish Colossal Squid Staff Member Moderator

    Joined:
    Jul 9, 2009
    Messages:
    2,832
    Likes Received:
    96
    Location:
    South Florida
    I have noticed with my pet briareus, Legs, always uses her two back arms for stability and security. For example when hunting she will explore and attack with her front six arms but always keeps the rear two on a rock or glass so she can use them to either retreat, or hold her self in place once the victim is caught. To me she has two legs and six arms.
     
  5. DWhatley

    DWhatley Cthulhu Staff Member Moderator

    Joined:
    Sep 4, 2006
    Messages:
    19,078
    Likes Received:
    1,123
    Location:
    Gainesville, GA USA
    Interesting that you should mention that because a large, public "watch the octo in the aquarium study" had aquarium visitors all over the world observe octopuses and record which arms they used. The intent was to see if there was evidence of octos being left or right handed (they suspect left and right brain functionality). The results of the data collection did not show any evidence of what they were looking for but did show what you are observing.
     
  6. ceph

    ceph Wonderpus Staff Member Moderator

    Joined:
    Dec 20, 2002
    Messages:
    198
    Likes Received:
    18
    Location:
    West Palm Beach, Florida
    I'm going to step in here. I am trained as a scientist and therefore may have a more narrow definition of science.


    The original work on octopus laterality was lead by Dr. Ruth Byrne and as done with controls and attention to observation biases. Two papers were published in peer reviewed scientific journals - while far from perfect, this peer review system is the best available method.

    If you use Google Scholar and key words “octopus, laterality, byrne” you can find the original abstracts.

    This work was covered in the media fairly accurately. This isn’t always the case.



    On to the current work.

    Be careful with reading to much into this recent study - or at least the reporting on it.

    Here are my concerns:

    Arms and tentacles are frequently confused - not a big deal and this could be a mistake the journalists, not the scientists.

    Of much more concern is "Some previous studies had found that octopuses favored one side over the other, and the explanation for this was that some were shortsighted or had visual impairments." If that refers to Ruth Byrne's work, the explanation "some were shortsighted or had visual impairments." does not fit my understanding of her work or octopus vision.

    There are papers on octopus arm use, for example: How Do Octopuses Use Their Arms?
    JA Mather - Journal of Comparative Psychology, 1998 and a lot of recent interest in the biomechanics of octopus arms. I’ve not read this in a while but am wondering if the results of this recent study are new.

    Observer bias/confusion could be a problem depending on how it was handled. We all interpret things differently. When several people are recording behavioral data, it is standard practice to test them against each other so something could be said about their consistency when scoring the same thing.

    It looks like the work is prelimary (not yet published in a peer reviewed journal).

    The majority of scientists do not release prelimiary results. Prior to publishing results most scientific journals require that the scientists sign a waiver that the results are new and not published elsewhere. If hey have already been released they are not new by definition. It is for this reason that the news of Dr. Kubodera and colleagues photographing the first live giant squid was not reported until a full year after the discovery.

    Does this mean this work isn't of value? That a very different question, and my answer is a strong NO. I would classify this study as education. It helped to get people to look in detail at octopuses (which promotes public education and involvement). Education is a very noble goal! Also keep in mind that my defintion of research, as a scientist, is narrow. Getting a lot of people to look at octopuses in an organized way is a very good thing which I fully support.

    Bottom line: To me this article provides some useful ideas to think about (especially the "2 legs idea) but I would be careful with the methods and conclusions. If the spin is that this is recent research, there are a lot of things that bother my inner scientist.


    Disclaimer: These are my personal thoughts and do not reflect the ideas or views of any institution or group that I am associated with.
     
  7. ckeiser

    ckeiser GPO Supporter

    Joined:
    Oct 16, 2008
    Messages:
    120
    Likes Received:
    1
    I would love to see a peer-reviewed study on that topic, but am also in full support of getting aquarium visitors "involved" in a scientific process. It may not follow the scientific method per se, but still cool for the participants.

    Mather's paper on octopus arms is great. Also, I've attached another of her papers dealing with this topic possibly more pertinently.
     

    Attached Files:

  8. DWhatley

    DWhatley Cthulhu Staff Member Moderator

    Joined:
    Sep 4, 2006
    Messages:
    19,078
    Likes Received:
    1,123
    Location:
    Gainesville, GA USA
    Ceph,
    I tried to make it clear that the referred to study (another word might be more appropriate :hmm:) was done with the public and not in a lab and was never intended as scientific work but instead to interest the public and, if the results suggested anything, to then do real research. I think the approach was terrific but, clearly not scientific. I do think mass observations and recordings would be helpful in coming up with study criteria.
     
  9. ceph

    ceph Wonderpus Staff Member Moderator

    Joined:
    Dec 20, 2002
    Messages:
    198
    Likes Received:
    18
    Location:
    West Palm Beach, Florida
    Right - I agree with both of you.
     
  10. mucktopus

    mucktopus Haliphron Atlanticus Staff Member Moderator

    Joined:
    Dec 31, 2003
    Messages:
    523
    Likes Received:
    51
    back from the field and coming in a bit late here- to address the original questions of the thread... I have been sent numerous videos claiming to show bipedal walking in bimacs, dofleini, and cyanea but none of these examples actually shows this- or is even close. A. aculeatus and A. marginatus both walk bipedally using only arms four (the ventral, or bottom pair). In these animals this is also the most robust pair. We have not yet seen bipedal walking in any of the octopuses (generally macropus group) which have very robust dorsal (top) arms.

    As James mentioned, Ruth Byrne's work shows pretty well that octopuses use particular arms for particular tasks. I also see this consistently in the wild (certain arms being used for defense, den maintenance, etc).
     
  11. Antropoteuthis

    Antropoteuthis Cuttlefish Registered

    Joined:
    Nov 7, 2009
    Messages:
    21
    Likes Received:
    0
  12. Stavros

    Stavros GPO Registered

    Joined:
    Jun 26, 2008
    Messages:
    165
    Likes Received:
    35
    Location:
    American University of Kuwait
    I've seen a bimac walking back (away from me) on L4 and R4 once at the very early days after we received it.

    The mantle was elongated with two black stripes on both sides.

    The rest of the arms were shaped as "L" (orthogonal with joints) and at the distal part of the arm had "cork-screw" tips.

    The octopus walked in this fashion towards the back end of the tank and then stopped (duration: 4-5 seconds), settled on all arms, with the mantle still elongated and settled horizontally on its right side. Then every couple of seconds the animal positioned its mantle vertically (at 90 degrees angle) to be returned to its initial position sideways on its right side. This continued for at least a minute, before moving in to its shelter and out of sight.

    This happened the day this thread was started and since then I tried to get it on video but I have never seen it repeating this behavior.
     
  13. DWhatley

    DWhatley Cthulhu Staff Member Moderator

    Joined:
    Sep 4, 2006
    Messages:
    19,078
    Likes Received:
    1,123
    Location:
    Gainesville, GA USA
    Of all the shots I have missed, there are two I REALLY regret not getting and may never see again. One was a photo of mercs mating where you could see a shoulder forming on the male. This one I missed because the camera I had at the time could not focus in the lighting even though I had plenty of time. The other was an incident like this when the behavior was unexpected (a bee like hovering and suspected attack attempt on my hand), likely to be common in the wild and never seen again in the aquarium. Soooo frustrating!
     

Share This Page