Does anyone else understand THIS PAPER]?
It is being widely reported as evidence that dogs orient to the magnetic field of the Earth when defecating (though apparently not when urinating).
The paper is full of complicated statistics and details about magnetic field fluctuations that are way beyond my mathematics and physics background. It is hard to think of a plausible reason why dogs would do this, though the authors take a stab at it. And they claim to “provide the first clear and simply measurable evidence for influence of geomagnetic field variations on mammal behavior. Furthermore, it is the first demonstration of the effect of the shift of declination, which has to our knowledge never been investigated before.” Quite an accomplishment, if true, but not surprisingly I’m a bit skeptical. Not any direct influence on vet med, but it would be both cool and weird if true.
Anyone have any thoughts?
Wow that was weird.
Unfortunately, I don’t have the patience to read it closely, but skimming it sure does beg more questions than it can answer.
Why? would be the first.
Wouldn’t it imply that a particular dog always, or usually, poops facing the same direction?
Aren’t there other stronger stimuli working on a dog’s position of defecating?
What does all that say about my neighbor’s dog, who went through a phase of having to poop right where I just finished taking my pee?
I’m not going to waste my time reading the paper. My wife and I have four dogs in our household, and I can assure you they orient themselves randomly while defecating. It would take me less than one week to document enough defecation events to refute this idea.
I’ve heard the same thing about why dogs circle a few times before lying down. Where are the magnetic detectors in dog’s brains?
Its easy to laugh at a study like this but it important to remember that this is a controlled experiment so the results may differ from our everyday experiences where many other variables come into play. We also need to keep in mind that the purpose of the study is not to find out which direction dogs poop in but to try and find some evidence that they are able to sense the earths magnetic field. They just chose this way to study it because its easier to quantify this behavior than if they were to try to test a dogs navigation abilities and prove that their success was due to their ability to sense magnetic fields.
Brennan I have to admit I’m a bit lost with the discussion of axial and angular vectors etc.
I have 2 dogs, and I will just have to follow them outside for a while to see which directions they face to poop…and why is the poop more important than the pee, I mean if they orient themselves to poop, why not when they pee? Or eat? or, or…
Macgyver, if dogs orient themselves to the Earth’s magnetic field they will need some mechanism to detect the field. I’ve looked into this in the past and no one has found such a mechanism. Couple that with the randomness dogs display when defecating and this study adds up to nothing.
Well, cows do like to face north when they sleep, it seems. Ramblers told to 'use cows as compasses' as they graze and sleep facing north | Daily Mail Online
If you're lost in the countryside without a compass, don't panic. Just look for a herd of cows and see which way they are pointing. After monitoring the behaviour of thousands of cattle, scientists have found that they tend to face north after aligning themselves with the Earth's magnetic field.
There was an article in Scientific American supporting this idea.
However, I notice that flocks of birds, sitting on the beaches in California, will all face the sun. i notice this mostly in the evening when hundreds of them gather and face west.
Lois
As weird as the idea seems, I certainly don’t discount it out of hand. Birds have been shown unequivocally to have structures for detecting magnetic fields, which they use in guiding migration. It’s a bit of a question whether or not mammals can do the same thing, and this paper purports to show that they can. I agree that confirmation would require some plausible mechanism/anatomic structure to be identified, and I’m not aware of any at this point.
The question of why dogs would do this is the first issue that occurred to me. What possible selective advantage could it have? The authors suggest that the detection of magnetic fields is intended for other uses (navigation in a territory, for example), and the alignment during defecation is a way of “calibrating” the system regularly, but I don’t find that especially convincing. And as Asanta points out, why would they do it when defecating but not urinating? Still, unanswered questions don’t automatically invalidate a hypothesis.
The paper troubles me in that it contains a large number of measurements most of which do not show a significant pattern and a couple of which do. This is often a sign that the data has been dredged until a significant result is found, which is a red flag for spurious findings. However, I don’t understand the variables well enough to know if the comparisons made are reasonable. It seems the dogs oriented randomly under some conditions but appeared to orient non-randomly under others (having to do with the stability of the magnetic field at the time), but again I don’t know enough about magnetic field measurement to know if this is an appropriate way to parse the results.
What we need are a physicist and a statistician to help us poor biologists figure this out!
I suppose you could see if it really has any correlation with the magnetic field by putting a dog in a confined small yard and placing two strong electromagnets one at the east and the other at the west end of the yard with the opposite charges facing the yard and watch to see if the dog orients itself along those lines during defecation.
Occam
Macgyver, if dogs orient themselves to the Earth's magnetic field they will need some mechanism to detect the field. I've looks into this in the past and no one has found such a mechanism. Couple that with the randomness dogs display when defecating and this study adds up to nothing.I agree Darron and I am not saying this study or any one study proves anything. In fact Mckenzie brings up some significant concerns about the data. On the other hand I am not confident enough in our understanding of biology and neurophysiology to say that an animal can not detect magnetic fields simply because we have not yet identified a structure in their body that can do this. I also think its important to note that our every day observations are so fraught with bias and uncontrolled variables that they are not a great yardstick for questioning the validity of experimental results.
I have been observing multiple dogs defecate in my back yard for years. Their orientation is random. Do you want me to post photos of my dogs pooping? Give me a week and I can blow this paper into little bitty pieces.
For my next trick, I will prove horses do not sleep standing up, and cows do not eat all pointing the same direction.
Geez people. Get out of the city once in a while and learn how nature works.
I’ve had dogs all my life too and while I have never noticed any pattern either that does not mean there isn’t a greater tendency for them to orient in one direction or another. The study does not say dogs all orient with their noses pointing north. It basically says that there was not an equal probability that they would orient along any of the 360 degrees available. Their orientation tended to bunch up a little more often on one side of the compass than wold be expected by random chance. As I mentioned above, mckenzie pointed out a possible problem with this study. Its also just one study so it could have been a fluke or maybe there was a poodle in heat down the block and her scent caused them to all line up in one direction.
Since we’re on the subject of studies that sound silly, if you ever get a chance take a look at the Ig noble awards]. They are given out every Sept to “honor achievements that first make people laugh, and then make them think.” The studies are interesting and the podcast of the presentations every year is actually very funny.
I've had dogs all my life too and while I have never noticed any pattern either that does not mean there isn't a greater tendency for them to orient in one direction or another.Our oldest dog orients herself parallel to the nearest fence. She also tries to hide behind trees. Yes, we have a modest dog. We used to have a dog that would turn 90 degrees to his left halfway through his defecation. One of our dogs will defecate, then walk about five to 10 feet, and finish defecating. He does not always face the same direction after he moves. Another of our dogs faces southeast or northwest when she defecates, depending upon which side of the porch she walked off. Our fourth dog goes out in the back yard and does his business without worrying about lining himself up with the Earth's magnetic field. He's just looking for a place out of the usual running path and not already occupied by a poop pile. This study is not worthy of an Ig Nobel because it is not even ridiculous. Edit: It's official. My wife and I watched the dogs poop after breakfast. As noted previously, they all faced different directions.
I had just finished reading Technopoly by Neil Postman a couple weeks back when I was visiting UAE.
This thread reminded me of one of his contentions that scientific investigation has been misused and has moved toward completely pointless aspects of our lives.
I had many cats when I lived in Saudi Arabia and I can tell you their orientation in the litter box would have had no impact on my life whatsoever.
(or anyone else’s for that matter)
I had just finished reading Technopoly by Neil Postman a couple weeks back when I was visiting UAE. http://www.amazon.com/Technopoly-The-Surrender-Culture-Technology/dp/0679745408 This thread reminded me of one of his contentions that scientific investigation has been misused and has moved toward completely pointless aspects of our lives. I had many cats when I lived in Saudi Arabia and I can tell you their orientation in the litter box would have had no impact on my life whatsoever. (or anyone else's for that matter)Did they face toward Mecca? Lois
A colleague of mine had some comments on the paper which I think are useful. Apart from the problem of multiple post-hoc comparisons, it doesn’t seem there is any sound, a priori rationale for the particular analyses done. Rather, when the primary outcome showed no effect, many other possible ways of parsing the data were employed rather indiscriminately in order, apparently, to find at least some statistically significant result. Not an unusual problem in scientific papers, unfortunately.
Short-term variations in the Earth’s geomagnetic field are caused by processes in the upper atmosphere – the ionosphere and the magnetosphere. Movements of charged particles in these layers of the atmosphere create large electric currents, and those electric currents necessarily produce magnetic fields that summate with the geomagnetic field, resulting in small changes in both intensity and declination (the difference between magnetic North and true North) of the local magnetic field measured at a point on the Earth’s surface. These short-term variations occur over minutes to hours rather than seconds and are very small – which is why when you look at a compass (away from interfering human artifacts) you do not see the needle moving around. As the authors state, the overall data in their paper show no evidence of North-South orientation (their ‘surrogate measure’ for detection of a magnetic field) at all. The authors then go on to do a post-hoc analysis = ‘data dredging’. They state very clearly in the Methods section that is what they are doing, but presumably do not realise the statistical problems inherent in doing so. They divide the data up in ways that were not specified a priori, e.g., by time of day or intensity of magnetic field variation or rate of magnetic declination variation, etc. (The rate of change of declination should be expressed not in % but in % per unit time.) For each they did a statistical test to see if the confidence interval around the average vector overlapped the N-S orientation. Note that, after each such dividing up, the numbers of dogs in each category are quite small, mostly in the few tens, and so the confidence intervals are correspondingly wide. They do not state how many such tests they did, but it is clear that it was quite a few. Because they did a lot of tests, there is a reasonable chance that at least one would orient close to N-S such that its confidence interval overlapped the N-S orientation, and so be statistically significant. Indeed, one of those tests (the one for measurements made when the rate of variation of magnetic declination was 0%) came up statistically significant, i.e., the average vector was more-or-less N-S. They concluded that (1) dogs can detect the Earth’s magnetic field but (2) only when the local magnetic field is not showing (tiny) fluctuations in declination. If one were to take the findings seriously then, strictly, results of such post-hoc analysis should be treated as ‘hypothesis generation’. Thus, this study has generated the hypothesis that dogs can detect the earth's magnetic field but only when it is stable and not showing tiny fluctuations in declination, and somebody can now test that prediction (any takers, anyone?). It is not implausible that dogs could detect Earth’s magnetic field because other mammals, e.g., the subterranean mole rats, certainly can (although it is easy to see good reasons why detection of the geomagnetic field could be evolutionarily useful for animals that spend pretty much their entire life underground). However, given that the Earth’s magnetic field declination fluctuates only a very small amount and does so for a lot of the time it would be very peculiar if dogs had evolved to be able to detect it only when it is not undergoing those tiny fluctuations! It is also difficult to think of a reason why dogs should use any such ability to orient themselves N-S when defaecating…
Maybe they just don’t give a sh*t.
I had just finished reading Technopoly by Neil Postman a couple weeks back when I was visiting UAE. http://www.amazon.com/Technopoly-The-Surrender-Culture-Technology/dp/0679745408 This thread reminded me of one of his contentions that scientific investigation has been misused and has moved toward completely pointless aspects of our lives. I had many cats when I lived in Saudi Arabia and I can tell you their orientation in the litter box would have had no impact on my life whatsoever. (or anyone else's for that matter)I dunno, if it turned out facing a litter box in one direction ensured that cats were more likely to use it, than something like the furniture, I'd think that would have an impact on some people's (and cats) lives.
This idea is clearly full of what the dogs are getting rid of.
If dogs truly did align with Earth’s magnetic field is such a way, humans long ago would have noticed and used them as natural compasses.