Bimac brains vs. scallop brawn

Discussion in 'Behavior and Intelligence' started by Joe-Ceph, Jul 27, 2008.

  1. Joe-Ceph

    Joe-Ceph Haliphron Atlanticus Supporter

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    I caught my bimac, Lefty, at low tide a couple of months ago. He's got about a 2 ½” mantle. I know that octopuses can open muscles and clams by drilling a tiny hole near the hinge and injecting a toxin (tranquilizer?), but Lefty hasn’t done this yet. He has brute-forced very small muscles open, but given up on 2" long ones, so when I found a 3" diameter rock scallop (which have thick shells) while SCUBA diving, I expected it to easily be strong enough to keep Lefty out, at least until he gets larger. I was wrong. Lefty demonstrated a technique for killing a scallop that I had never suspected; he suffocated it. He opened his body like a 6" wide parachute and draped it over the scallop. When the scallop opened (about 3/4" max) and tried to draw water inside, the thin membrane of Lefty's body would seal against the edges of both halfs of the shell and just bow inward. The scallop couldn't get any new water, and after about 20 minutes, Lefty was crawling into the dead scallop. Lefty didn't use strength to hold the scallop closed, he just used his body like a plastic bag and denied oxygen to the scallop until it suffocated.

    Lefty could only eat a small fraction of the scallop because it was so large, and I was impressed that he was able to use such an indirect, almost passive, technique to prevail where a direct approach would have failed. I suspect that this might be how they kill fish too.

    I imagine that this is not an uncommon behavior, is it?

    I think that this technique must be largely instinctual, since there was no trial and error or experimentation involved, Lefty just saw the big clam, enveloped it, and patiently suffocated it. I wish I could give Lefty credit for being so intelligent as to have reasoned out that this would work, and invented it on his own, but there's no way he's that smart (It took ME ten minutes just to realize what he was doing!). Instinct must have handed him this technique. What do you all think?

    On the other hand, where was instinct when Lefty was unable to open little 2" long muscles? The suffocation trick might not work on muscles, which can "hold their breath" for hours between tides, but why didn't instinct tell him to drill a little hole in them with his radula and inject his tranquilizer? He just wrestled with them for a while and gave up. Will he have to deduce the drill a hole trick, on his own, or is he simply to small for that to be an option. I've saw a full grown bimac do it, so maybe size matters when it comes to radulas.

    Thoughts?
     
  2. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    This still may be trial and error but learned before you acquired him and then remembered. Since you are feeding him the same foods he found while growing up, he may have a preference and not work on the food that is harder to open based upon already acquired technique.
     
  3. cuttlegirl

    cuttlegirl Colossal Squid Supporter Registered

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  4. Joe-Ceph

    Joe-Ceph Haliphron Atlanticus Supporter

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    Thanks for the links - very interesting. The article didn't mention suffocation as a technique, and I haven't been able to find any reference that suggest that octopus employ this technique. I'm starting to wonder if I made a rash assumption about what Lefty was doing for 20 mintues. It is possible that he was drilling a hole in the center of the scallop shell (where the muscle is) and that holding himself steady just looked like suffocation to me. I foolishly discarded the scallop shells without closely examining them ("Bad scientist! No biscuit!"), so I'll need to bring another scallop home and try it again.

    I'll add to this post in a week or so after I get another rock scallop and conclusively determine weather C.O.D was suffocation or cephalotoxin. In the mean time it is best to think of this like a Big Foot sighting.
     
  5. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    Awww, I just enlightened Neal about your interesting observation and now I am going to have to take it back.

    I'm glad Jennifer found that link, I was feeling guilty about not trying to find it myself :oops:

    I am not sure how Octane opened the first couple of clams I gave him either (I did check for drill holes :razz: but there were none). I almost wonder if the starfish managed the task. There have been two clams in his tank for several months now, both have been moved and both are still quite alive. One managed to dig itself under a rock but the other Octane took back to his sleeping quarters.
     
  6. Guero

    Guero Pygmy Octopus Registered

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    Hey Joe, I'm in SD as well, we'll have to compare notes soon...........
     
  7. Steve O'Shea

    Steve O'Shea Colossal Squid Supporter

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    OK, a long time ago, in a another life, I either had a dream, read something, or observed something. Whatever it was, I know that not all octopus species drill, and I think those that do have a radular-like tooth (or several) in their salivary papilla that is used for the actual drilling (rather than the radula proper). The salivary papilla drops a dob of acid(?) on the shell that it intends to drill, and the tooth assists in the actual drilling.

    Octopuses actually have three series of teeth in their buccal bulb: the radula proper, palatine teeth on the faces of the palps either side of the buccal mass, and (some) a radular-like tooth in the salivary papilla. I don't know if a bimac has this tooth.
     
  8. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    Steve,
    Thanks for the impromptu bio lesson. I wish you would do more tidbits like this as those of us that are not official students can remember :old: these little gems and it is helpful in understanding our pets.
     
  9. Steve O'Shea

    Steve O'Shea Colossal Squid Supporter

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    I wish so too D, but the field is so vast and the interests of those online so diverse that it's actually very difficult to stay on top of things. I don't have much of a life as it is.
     
  10. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    Humm, maybe an alternate to scrubbing test tubes one part of a semester would be to collect and post little known, interesting ceph bio tid bits ... just a thought for some of your freshmen ... :sagrin:
     
  11. Lime

    Lime O. vulgaris Registered

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    Well I think this is kind of strange. But I would also like to give Lefty a ton of credit for being so smart.

    Btw, I have a couple questions. Where did you catch the Bimac? And when I ever get my octopus, may I steal the name Lefty? I really like it. :)
     

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