Alignment of the body (along the thoracic spine) in direction towards the head (heading) was measured in freely moving dogs (i.e., not on the leash) in “open field” (on meadows, fields, in the wood etc., i.e., unconstrained, and uninfluenced by linear structures, such as walls and fences) away from the road traffic, high voltage power lines, and conspicuous steel constructions during defecation and urination by a hand-held compass.
So it was not as simple as directional preference in sidewalks or roads.
The research seems credible, and they've convincingly excluded obvious things like that they're actually aligning with the sun.
The striking thing is that they only align N-S when the declination of the magnetic field is stable, but when the declination is changing they don't align. The differences in magnetic field direction is only a few degrees, so it's amazing that a dog whose head is flopping around can detect such small changes.
>they've convincingly excluded obvious things like that they're actually aligning with the sun.
I don't know - for my taste, to exclude alignment to the sun they would have had to keep the dogs in a closed environment with an artificial light source. After all, even with clouds present you know where the sun is (and you can still get sunburned etc.)
It also rings my "skeptical" alarm bells when they cite the "original" evidence that cattle aligns along the N-S axis, but they don't cite the paper that fails to replicate the "original" findings in cattle: http://link.springer.com/article/10.1007%2Fs00359-011-0628-7
It also is unlikely that humans would be an exception here. However, my money still is on "Extraordinary claims require extraordinary evidence". Animals may be capable of magnetoception, but I don't think that has been proven yet.
For example, those foxes could try and minimize their shadows or changes in their shadows. They might do that using an internal clock. Alternatively, they might be able to perceive the polarization of the sky, and use that to guess where the sun is (note the high variation in successful angles)
I remember seeing a show remarking on similar sensitivity being observed in foxes when hunting mice in the snow. Apparently, the fox is much more accurate when diving when facing north.
Typically, the daily declination comprises westward-shifts in the morning and eastward-shifts
in the afternoon, while the magnetic field is rather stable at night [21,22]. This calls for
necessity to test whether the dog alignment is not actually influenced primarily by time of the
day and most probably by position of the sun on the sky. We can, however, exclude this
alternative. First, days when the magnetic field parameters change erratically and
unpredictably (i.e., magnetic storms) are quite frequent. These changes have been well
studied by others and are described in the literature (cf. [21,22] for reviews). Second, the data
collection was not biased to either morning or afternoon (Table 8). Third, periods of sampling
under conditions of quiet magnetic field were rather evenly distributed in the course of the
day. Fourth, and most importantly, alignment during excreting was apparent under conditions
of quiet magnet field, irrespective of the time of day or month. Time of day per se was not a
reliable predictor of expression of alignment (Figure 2, Tables 3, 9). Fifth, generally, there
are on average 1,450 sunshine hours per year at maximum in the Czech Republic and in
Germany, on localities where measurements were done. Even if we would assume that these
sunshine hours were evenly distributed over the daylight period and the year (as our
observations were), there would only be a probability of 33 % that the observation was made
when the sun was visible. Hence, with high probability (67 %) most walks during the
daylight period were made when it was cloudy.
Well, I'm in that hemisphere. My dog prefers to do it facing away from owner if no reference points, otherwise always likes to go parallell to the nearest path/ building/ fence. I would say virtually never randomly chooses south.
The largest issue affecting verification of an animal magnetic sense is that despite more than 40 years of work on magnetoception there has yet to be an identification of a sensory receptor.
I remember having read about this effect in homing pigeons, and the Wikipedia article also mentions that:
These results suggest that magnetite located in the beak of pigeons may be responsible for magnetoreception via trigeminal mediation. However, it has not been shown that the magnetite located in the beak of pigeons is capable of responding to a magnetic field with the Earth’s strength. Therefore the receptor responsible for magnetosensitivity in homing pigeons has not been cemented.
Without being an expert, it seems to me to be worthwhile research.
I don't think they're saying it is limited to dogs. It's just proven in dogs. Dogs behave really oddly when a natural disaster is about to occur, would it be that surprising that they had an unique sense that us humans don't have such as what this study is suggesting?
Alignment of the body (along the thoracic spine) in direction towards the head (heading) was measured in freely moving dogs (i.e., not on the leash) in “open field” (on meadows, fields, in the wood etc., i.e., unconstrained, and uninfluenced by linear structures, such as walls and fences) away from the road traffic, high voltage power lines, and conspicuous steel constructions during defecation and urination by a hand-held compass.
So it was not as simple as directional preference in sidewalks or roads.