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Special Molecule Gives Birds a Magnetic Biocompass

Posted by ScuttleMonkey on Mon Sep 11, 2006 08:37 PM
from the bio-magneto-driver dept.
Aaron Rowe writes "CORDIS news reports that a team of scientists has identified a family of molecules called cryptochromes that allow migratory birds to sense magnetic fields. Curiously enough, these molecules only function when accompanied by blue light. The article also mentions, 'The researchers also suggest that, as cryptochromes have been strongly conserved throughout evolution, all biological organisms could have the ability to detect magnetic fields, even if they do not use them.'"
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  • Hrm... (Score:5, Funny)

    by PieSquared (867490) <isosceles2006@gmail. c o m> on Monday September 11 2006, @08:41PM (#16086045)
    Where do I sign up to get these powers enabled? I totally would go for it, even if it is a really lame 6th or 7th sense. Like, if I was lost in the woods with no cell phone and nothing to make a shadow with, and no running water... it could be mildly useful!
  • by WindBourne (631190) on Monday September 11 2006, @08:46PM (#16086063) Journal
    When he gets off the plane at DIA, his first question is which way to north. Once he has his berings, he always knows his directions. Even when traveling through the mountains, day or night, he is able to figure out the direction quickly. Pretty impressive. What I find interesting is that plane travels screws him up. Once on the ground, If he does not get his bearing quickl, he appears to get more uncomfortable as time passes.
    • by smilindog2000 (907665) <bill@billrocks.org> on Monday September 11 2006, @08:56PM (#16086116) Homepage
      We do have a built-in gyroscope, though not a compass. I'm pretty sure guys have a stronger sense of it then girls. Makes sense... hunting and all.

      I have a good sense of direction, but now and then I get all messed up. It's a really strange feeling when I realize this has happened, and the internal gyro has to flip 180 degrees. There's a sense of the world shifting, almost like motion.
      • I can usually find north, though I like to think I have a built in Inertial Guidance System rather than something as simple and mundane as a gyroscope and compass.
      • I have much the same thing. But I also have a special case.

        First time I visted a friends house, it was night time, and my sense of direction got flipped (I also wasn't driving). It now seems to be stuck that way. I can drive out there and tell exactly when my sense of north does a 180. Driving through a cutout in a hill, can't see anything but the sides of the trench, when coming from one direction, and from the other direction its a set of curves that are bounded in by dense trees.

        So, gyroscope, yes, but i
      • by WindBourne (631190) on Monday September 11 2006, @09:05PM (#16086153) Journal
        This guy is able to tell you north, south, east, and west in mountain canyons, or even in buildings. He is not able to give degrees, but he can point in roughly 30-45 degree increments. Pretty impressive. Over the years, I have been impressed with some capabilities. One guy that I knew had 6/20 vision. He had doctors everywhere wanting to study his eyes. But he wanted to be a pilot so told them to take a hike.
        • by Doc Ruby (173196) on Monday September 11 2006, @10:42PM (#16086471) Homepage Journal
          6/20 vision [wikipedia.org] (assuming you're using the British/meters notation) means your friend had to stand 6 meters from something that others can see clearly at 20 meters. The only doctors wanting to study those eyes would be optometrists wanting to sell him glasses.
                  • No way, that stuff messes up your brain! Math just... okay, math messes up your brain too.
            • by cryptoluddite (658517) on Monday September 11 2006, @10:41PM (#16086466)
              All the things you've said are really pretty easy to do by consciously or unsconsciously updating your bearings by observation. Most human-made buildings are highly regular, even when designed to be confusing. Many times there are subtle clues that you don't pick up on that he probably does, such as the distant hum of a generator or type of vibration in the floor or the grain of the carpet.

              These feats are nothing special really. Everybody has them to some degree, whether it is direction, or time, or reading expressions, or perfect pitch, or anything else. For instance I can set a 20 min pizza timer and go play a video game, pause it, and walk out with <5 seconds left on the timer. This happens very often. Do I have some magic genes that give me some digital internal chronometer? Doubtful, more likely I just have it in the back of my mind all the time.
      • Re: (Score:3, Insightful)

        I'm pretty sure guys have a stronger sense of it then girls. Makes sense... hunting and all.

        And the female job of gathering fruit, vegetables, and herbs from remote areas of the forest or savanah or whatever doesn't require a sense of direction.

    • Even when traveling through the mountains, day or night, he is able to figure out the direction quickly.

      Use of the sun by day or stars by night.

      What I find interesting is that plane travels screws him up. Once on the ground, If he does not get his bearing quickl (sic), he appears to get more uncomfortable as time passes.

      Jetlag or simple fatigue from air travel.

    • by OverlordQ (264228) on Monday September 11 2006, @10:47PM (#16086487) Journal
      When he gets off the plane at DIA, his first question is which way to north.

      Um, if he actually could sense the magnetic field, he could tell which way was north and which was south. Thank God we dont have to tell magnets which say is 'North' to get them to work.
  • Radio (Score:5, Funny)

    by Spazmania (174582) on Monday September 11 2006, @08:47PM (#16086067) Homepage
    And since radio is just a modulated electromagnetic signal, we should be able to pick up Rock 'n Roll on our teeth by exposing them to blue LEDs. It remains only to train our brains to understand this new sixth sense...
  • Where he was reading Brief History of Time and read "light is effected by gravity", to which he concluded that it was easier to drop things in the dark.

    -1 offtopic.

    Mind you, maybe I could strap a blue LED to an albatross and find my way home when I'm drunk.

    +1 ontopic.
  • I hope they don't get too confused:

    http://science.slashdot.org/article.pl?sid=04/05/1 5/1544240 [slashdot.org]
    http://digg.com/general_sciences/North_Pole_Moving _South_ [digg.com]

    No wonder those latent genes are turned off.
    • What's interesting though is that there doesn't seem to be any fossil evidence of higher-than-normal extinction rates during previous pole reversals...
        • Re:Extinction (Score:5, Informative)

          by FleaPlus (6935) * on Monday September 11 2006, @10:23PM (#16086420) Homepage Journal
          I think you've just hit upon a new theory as to why the dinosaurs went extinct. Is there any evidence, for or against? How well are the dinosaur extinction event and the magnetic pole flips narrowed down, and could the dinosaur extinction be a delayed reaction?

          Well, the thing is, magnetic pole reversals actually happen pretty often, according to Wikipedia [wikipedia.org] at a rate of 1-5 events every million years. Since the dinosaurs lived 65-230 million years ago, by looking at this graph [wikipedia.org] we can deduce that during their existence they experienced a few dozen pole reversals.

          Now that I look at it though, it is somewhat interesting that the Cretaceous Long Normal [wikipedia.org], an abnormally long (~40 million year) period during which there were no pole reversals at all, ended around 15 million years before the dinosaurs disappeared. I personally think it's just a coincidence, though.
          • Re: (Score:3, Insightful)

            Any brief event that requires fifteen million years to exert an extinction is probably not the cause of said extinction. In fact, it's not even a coincidence as a coincidence requires concurrence in time.
    • Re: (Score:3, Insightful)

      Well despite what movies like The Core will make you believe, its not like this is their only way to tell where they are going. I believe they primarily rely on sight and memory, they are not just flying around there with their eyes closed.

      Of course there is only one way to find out for sure. Tie big magnets to the bird's heads and see if they can still find their way South. If not, we know it plays a big role in their navigation. Either that or it weighed them down so much they couldn't fly.

  • Hey birds! (Score:5, Funny)

    by cryptochrome (303529) on Monday September 11 2006, @08:52PM (#16086093) Homepage Journal
    I'm way ahead of you.
  • I know birds aren't smartest creatures, but I don't remember if they can memorize there migration path (though I assume not.) Could the hightening of this magnetic sense during certain seasonal light conditions direct the birds to follow the earth's magnetic field, guiding them until they encounter an area with lighting conditions sufficient to disrupt the sense?
  • F=IL X B (Score:5, Insightful)

    by afmstuff (954673) on Monday September 11 2006, @08:55PM (#16086110)
    This is interesting in the sense that these are very low frequency (~0Hz) fields which transfer much less power to the molecule which interacts with it than say visible light which operates at a much higher frequency and is comprised of a coupled electric and magnetic field. Of course the latter has been known to be sensed by sighted animals for quite some time. One way to view this is as an extension of the mechanism of vision- a photon causes a fast (actually one of the fastest reactions known) trans->cis conformational shift in retinol which drives a voltage down the optic nerve... the mechanism described in the FTA is the next step: once a radical is formed, it responds in a magnetic field. Apparently this response is also sensed. Interesting finding!
  • Iron in your nose (Score:5, Informative)

    by TubeSteak (669689) on Monday September 11 2006, @08:57PM (#16086121) Journal
    According to http://everything2.com/index.pl?node=nose [everything2.com]
    • There's a compass in my nose?

    • All humans have a trace amount of iron in their noses, a rudimentary compass found in the ethmoid bone (between the eyes) to help in directional finding relative to the earth's magnetic field.

    • Studies show that many people have the ability to use these magnetic deposits to orient themselves-even when blindfolded and removed from such external clues as sunlight-to within a few degrees of the North Pole, exactly as a compass does.

    • Though no one knows how this "sixth" sense is processed by the brain more then two dozen animals, including the dolphin, tuna, salmon, salamander, pigeon, and honeybee have been found to have similar magnetic deposits in their brains to help them in navigation and migration.


    I will dispute their statement about pigeons though. I recall watching or reading something where the scientists put trackers on homing pigeons to discover how they found their way around. Turns out they follow landmarks.

    The pigeons often took indirect routes, because they were following a road. The scientists didn't figure this out even after they realized the paths were very odd... it didn't click until someone looked at a road map.
  • by DrLudicrous (607375) on Monday September 11 2006, @08:59PM (#16086128) Homepage
    Anecdotally, I have heard of many people "sensing" the magnetic field of an MRI scanner. I have had a few MRI's done on myself, and can attest to this feeling. It is strange, mostly in the head, somewhat like when one feels dizzy or just a tinge of seasickness. I think that is has something to do with the fact that as you enter the scanner, the field you experience changes quite rapidly. Once you are in the scanner, I haven't really noticed the queasiness as much, though it still feels strange. However, I attribute this second sensation more to the fact that one is contained inside a small tube with all kinds of weird noises and vibrations going around. So at the very least, some people seem to be sensitive to changing fields above some threshold.
    • Usually that sensation is followed by the sound of a metal plate ripping through the back of your skull and adhering firmly to the inside of the scanner.
    • Re: (Score:3, Informative)

      The same thing happened to me once, when I was working to prepare an MRI scanner for an experiment. There was a radiologist there, so I asked him what the mechanism was, and he said it was believed that the magnetic fields affect metal ions in your otoliths [wikipedia.org], which are the organs in the inner ear responsible for sensing motion. Apparently it's known that some fish and birds have magnetic materials in their otoliths, but I'm not sure if it's ever been demonstrated directly in humans.

      Also, it's known that
        • by DrLudicrous (607375) on Monday September 11 2006, @10:00PM (#16086337) Homepage
          You are right in some respects. The moment to which you refer is the nuclear magnetic moment of the hydrogen atom, which are quite plentiful in most living things, ourselves included, due to the prevalence of water. In MRI, the torque these moments experience causes them to change their alignment from being in the same direction as an externally applied magnetic field (hence the big MRI magnet), to one that lies perpendicular to the direction of the external field. As they do this, the precess about the external field axis at a rate called the "Larmor frequency" (i.e. they rotate about it). This causes the magnetic flux inside the MRI receiver coil (more or less a loop of wire) to change, and by Lenz's Law, an EMF (voltage) will be induced. This is the signal that is detected.

          Note that while the magnetic moments are being manipulated, the actual water molecules themselves are more or less unaffected. This is one reason that MRI/NMR is such a great way to measure molecular self-diffusion- the phenomenon of diffusion is unaffected by all the magnetic fields being bandied about the sample. So to sum up, the "torque" the water molecules experience is one that affects only the magnetic orientation of the hydrogen atoms in your body, and not the actual physical orientation. And the signal that an MRI machine detects is not coming from the return to equilibrium of the water molecules as much as it comes from the precession of the asffected magnetic moments about the direction of the external field.

  • ...no midichloreans joke yet?
  • Why Blue Light? (Score:4, Interesting)

    by NexFlamma (919608) on Monday September 11 2006, @09:31PM (#16086234) Homepage
    They mention the blue light necessity of this system, but they never really explain why it has to be blue light or what the light itself does (unless I've become illiterate). Can anyone explain (or at least make something plausible up) the whole blue light component of this mechanism?
    • Re: (Score:3, Interesting)

      The current theory is that certain (blue-ish) frequencies of light create radical pairs--charged particles--that are affected by the Earth's magnetic field. Some (unkown, I believe) mechanism detects the effect on these particles (perhaps a Hall voltage?) and interprets that as magnetic field information.
  • by Anonymous Coward on Monday September 11 2006, @10:14PM (#16086383)
    I've know for a long time that many large birds freak out when a red laser pointer is shown anywhere near them. Especially large parrots. I'm not talking about pointing in their eyes, which is cruel to any animal. But just shining the red light nearby is enough to agitate them, and if shown near their head they will lose balance and fall from their tree.

    These light sensitive molecules must be very important to the bird's balance as well as helping them migrate. I wonder if they use the magnetic field to remain upright as well, or if by the red light turning off the receptor magnetic-sensitive light receptor molecules, they temporarily go blind. REd light could be perceived to be much brighter to them than the other colors. Since if the red light shuts off the receptors, only a small amount must be blinding. It might be like flipping a light switch where all blue and green perception disappears and only red is left. I"m glad my eye's aren't affected by specific colors that way.
  • by Fantastic Lad (198284) on Tuesday September 12 2006, @12:24AM (#16086768)
    Why does everybody assume that the trigeminal nerve (or this newly discovered molecule) in homing pigeons is used for navigation?

    Is it because we have learned how to use magnetics for navigation, so we therefore assume that animals capable of sensing magnetic fields must use it for navigation as well? The problem is that this is a false assumption.

    --Birds can sense magnetic information. However, when the olfactory nerve is cut, they get lost even when the trigeminal nerve remains intact. Birds which have had the trigeminal nerve cut but which had the olfactory nerve left intact could find their way home. So the claim is that being able to sense magentic fields was not required for homing pigeons.

    Still, it is generally accepted that homing pigeions have the wetwork required to sense magnetic fields. And if not used for navigation, then what? Why did such a sense develop?

    Put another way, what other perceptive planes of information exist which might make being able to sense EM fields useful?

    ALL organisms might have this ability?

    Chi-wiz.


    -FL

    • We should be training these birds for credit card validation...

      One quack good/accepted, two quacks bad/rejected.

      Definately better than those stupid card swipe machines!
  • by Splinton (528692) on Tuesday September 12 2006, @02:32AM (#16087044) Homepage

    According to a recent New Scientist article [newscientist.com], homing pigeons use their nose to find home rather than the Earth's magnetic field.

    From the article:

    She released 48 inexperienced homing pigeons 50 kilometres from their home loft. Half of them had had their olfactory nerve severed and half their trigeminal nerve, which is responsible for magnetic navigation. The next day, all but one of the birds deprived of their trigeminal nerve had returned home. Only four without a sense of smell returned (The Journal of Experimental Biology, vol 209, p 2888).

    • Hmm, between the 24 hour news network's focus on 9/11, nearly all my RSS feed speiling off 9/11 headlings, my news sites providing indepth coverage, and of course any remotely entertaining channel running 9/11 specials since friday, I hadn't even noticed. I would perfer not to have a 9/11 story unless its new news; I don't want to sound insensitive but anything and everything that could possibly be said or shown has been running reel-to-reel everywhere else today.
    • Scroll up. Look. "NEWS FOR NERDS. STUFF THAT MATTERS." In what way does it matter that the Earth has rotated around the Sun approximately 5 times since 9/11/2001? And it's certainly not news, last time I checked the Earth went round the Sun every year. And there's definitely nothing nerdy about this - unless you mean the general nerdy interest in mayhem and destruction.

      ...downright strange that there hasn't been ONE main story about it today.
      Are you expecting /. to manufacture news just to fit the theme you expect?
    • by Rix (54095) on Monday September 11 2006, @09:02PM (#16086141)
      Oh get over it already. All of you have been running around like a little girl with a skinned knee for 5 damned years. Suck it up.
    • Er... hate to be a typical /. geek, but didn't you mean "what is the difference between a /. moderator and a battery?" A magnet has no positive or negative side.
    • Re: (Score:3, Informative)

      Blue light? This is possibly a stupid question, but isn't sunlight yellow?

      Yes, but skylight is blue.
    • by Alfred, Lord Tennyso (975342) on Monday September 11 2006, @11:57PM (#16086676)
      It's a very badly written press release. In fact the actual science has zilch to do with birds and everything to do with plants using the same molecule. They described the way light and magnetic fields interact to change the way the plant stem grows, except in plants without the cryptochrome molecule.

      Which is just basic, everyday scientific advancement: a very small and excruciatingly dull thing, presented with a tie-in to something more interesting in an attempt to look sexier and get funding. Scientists hate doing it, but if you want to keep doing science, that's what you do.

      This article IS news, but only in the narrowest sense: new information. But after you take that new information, tie it in to something more interesting but only indirectly related (which you put at the front of the press release, and the actual new stuff at the end), then summarize it for Slashdot (skipping the stuff at the end), "news" becomes "olds".

      One final note: when I call the work "small", I don't mean to dis the grad students who worked thousands of hours tending the plants, measuring them, putting that data into the computer, analyzing that data, probably cutting them open and measuring that... such immense grunt work for a minor advance [promptly blown up into something irrelevant by university's press department] is the heavy-lifting of science. It's gotta be done but it's not glamorous or even interesting.