mutualism b/w octos and hermit crabs?

Discussion in 'Diving & Ceph Encounters' started by anat.incor.octo, Jul 7, 2006.

  1. anat.incor.octo

    anat.incor.octo Larval Mass Registered

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    hi...i'm a new member! :grin:
    right now i'm in South Caicos (Caribbean) taking a marine ecology class. for the past few weeks i've been checking up on a caribbean reef octopus that lives near the school's dock. i had only seen him inside his den up until last night when i finally saw him half out of it. unfortunately, my dive light scared him back inside, but as i watched, i realized he wasn't the only guy in the neighborhood. at least 20 hermit crabs were crawling in and around his den, at one point even completely blocking the entrance for a good 20 minutes. i have never seen so many crabs at once before, much less around a predator's den!
    i assume they were there scavenging empty shells from the octo's latest meal (of which there are always many scattered about), but still i was surprised--i have never heard of anything like it!
    can anyone shed some light on this?
    thanks!
     
  2. Taollan

    Taollan Vampyroteuthis Supporter

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    I have noticed this as well with the giant Pacific octopus, and in fact there is a whole host of organisms that will be living in a GPO's midden, including hermit crabs, umbrella crab (cryptolithodes), and many snails. There is a paper on this relationship in GPO dens that includes many other associates such as sculpins and starfish:

    Hartwick EB, Thorarinsson G (1978) Den associates of the giant Pacific octopus, Octopus dofleini (Wulker). Ophelia 17(1):163-166

    I hope this helps out a little bit.
     
  3. Fini

    Fini Wonderpus Supporter

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    They probably love the Octo's leftovers being the messy eaters they are.
     

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