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Thread: Octopus:

  1. #1

    Octopus:

    Octopuses

    From Wikipedia http://en.wikipedia.org/wiki/Octopus

    Octopuses have a relatively short life expectancy, and some species live for as little as six months. Larger species, such as the giant pacific octopus, may live for up to five years under suitable circumstances. However, reproduction is a cause of death: males can only live for a few months after mating, and females die shortly after their eggs hatch. They neglect to eat during the (roughly) one-month period spent taking care of their unhatched eggs, eventually dying of starvation. In a scientific experiment, removal of both optic glands after spawning was found to result in cessation of broodiness, resumption of feeding, increased growth, and greatly extended lifespans.[6]

    Octopuses have three hearts. Two branchial hearts pump blood through each of the two gills, while the third is a systemic heart that pumps blood through the body. Octopus blood contains the copper-rich protein hemocyanin for transporting oxygen. Although less efficient under normal conditions than the iron-rich hemoglobin of vertebrates, in cold conditions with low oxygen pressure, hemocyanin oxygen transportation is more efficient than hemoglobin oxygen transportation. The hemocyanin is dissolved in the plasma instead of being carried within red blood cells, and gives the blood a bluish color. The octopus draws water into its mantle cavity, where it passes through its gills. As mollusks, their gills are finely divided and vascularized outgrowths of either the outer or the inner body surface.
    Octopuses are highly intelligent, possibly more so than any other invertebrate. Although they have large brains, over a third of their nervous systems are located in their arms. Note that they are called arms and not tentacles, which usually have suckers at the tip. The sensory system controls colors of the skin, allowing the octopus to mimic the coral behind them and even other fish (lion-fish) and animals (eels). Unlike mammals, the octopus sensory systems do not map somatotopically to the brain. However, they have keen eyesight and have remarkable visual and sensory memories. They can recognize and recall people, shapes, and textures. They can use tools and solve complex spatial puzzles.

    How do octopuses have sex? Male octopuses have a specialized arm called a hectocotylus that can deliver sperm when inserted into the mantle of a female octopus. In benthic octopuses, the hectocotylus is usually the third right arm, counting from the most dorsal arm. The male dies within months after mating. The female can keep the sperm alive in her mantle for weeks until her eggs are mature. After the eggs are fertilized, the female may lay as many as 200,000 eggs. After having sex and laying eggs, the female octopus stops eating and dies after a month taking care (brooding) of the eggs. This gives new meaning to the word broodiness.

    The impulse to die after sex comes from two optic glands located near the eyes. If these glands are removed after spawning, the female octopus resumes eating, grows, and lives much longer. A nerve to these glands normally inhibit them from secreting hormone. If the nerves are cut in a young octopus, the gonads undergo precocious maturity. In females, the gonad size increase 100-fold within 5 weeks. If the optic glands were cut out, oogonia to oocyte cell divisions will not occur. Male and female octopus secrete the same hormone. If glands from Octopus vulgaris (O. vulgarism), as well as Eledone moscata or Octopus macropus, are implanted into another octopus, they cause gonadal enlargement, regardless of the sex and species of the octopus. However, implants from Sepia officinalis or Loligo vulgaris are ineffective. See attached paper.

    What do octopuses eat? Octopuses fall into two categories, ones that live in the deep ocean and have cilia called cirrina on their arms and ones that are bottom dwellers. The former eat mostly prawns, fish, and other cephalopods. The latter eat crabs and mollusks, such as clams and whelks, by drilling a hole in them with their beaks and injecting paralyzing saliva into them. Amazingly, in large aquaria, octopuses have been observed to attack and kill sharks. So, they can hold their own against the most vicious predators of the seas.

    So, why I am posting about Octopuses? This is because Octopuses can regenerate their arms. One seldom sees a seven-arm or fewer-armed octopus. If the tip of the arm is cut off, the octopus carries on its normal activity. By day 28, a mass of stem cells and blood vessels accumulate at the tip. Within 100 days or so, the arm tip grows back. Apparently, the growing tip expresses high concentrations of acetylcholinesterase (AChE), the enzyme that breaks down acetyl choline. Acetyl choline is the neurotransmitter of motor neurons.

    http://blogs.scientificamerican.com/...ate-with-ease/
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  2. #2
    Senior Member JimD's Avatar
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    Fascinating - I was unaware of their regenerative abilities - thanks, Wise!
    If you haven't seen it, the following video (from TED) offers a spectacular look at camouflaging/mimicking/signaling abilities of various cephaolpods. The relevant segments begin at about 1:50; the last 30 seconds or so are really phenomenal!

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    Super Moderator Sue Pendleton's Avatar
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    And I just thought they taste good.
    Courage doesn't always roar. Sometimes courage is the quiet voice at the end of the day saying, "I will try again tomorrow."

    Disclaimer: Answers, suggestions, and/or comments do not constitute medical advice expressed or implied and are based solely on my experiences as a SCI patient. Please consult your attending physician for medical advise and treatment. In the event of a medical emergency please call 911.

  4. #4
    They are clever animals. This video of an octopus carrying its own protective coconut shell is great:

    http://www.youtube.com/watch?v=1DoWdHOtlrk

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    Senior Member JimD's Avatar
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    Don't know what happened to the link I (thought I?) referenced above

    Here it is again: https://new.ted.com/talks/david_gall..._astonishments

  6. #6
    I just had a piece of Calamari transplanted into my spinal cord and my big toe is moving now. I will update as this experiment progresses

    Anyhow, interesting info, I realize Calamari is actually squid, I wonder if squid have short lives like Octopuses? I'll have to google that one I guess.
    "Life is about how you
    respond to not only the
    challenges you're dealt but
    the challenges you seek...If
    you have no goals, no
    mountains to climb, your
    soul dies".~Liz Fordred

  7. #7
    Senior Member Stormycoon's Avatar
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    Newts spinal cords self regenerate.. they used that depiction in the new spider man film. cross species engineering. but the professor had a missing arm and used it for that regrowth. some medical alteration.. ..Ahlfors from New World Labs mentions or has used this tool in his work. yet advanced destruction of key answers... great...
    I am not your rolling wheels
    I am the highway
    I am not your carpet ride
    I am the sky
    I am not your blowing wind
    I am the lightning
    I am not your autumn moon
    I am the night, the night..

  8. #8
    Well at least spider man films are getting a little more real to life
    "Life is about how you
    respond to not only the
    challenges you're dealt but
    the challenges you seek...If
    you have no goals, no
    mountains to climb, your
    soul dies".~Liz Fordred

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