Dogs can sense weak magnetic fields...

Dogs can sense weak magnetic fields...  Here's the conclusion from a recent study (note: MF means the Earth's natural magnetic field):

It is for the first time that (a) magnetic sensitivity was proved in dogs, (b) a measurable, predictable behavioral reaction upon natural MF fluctuations could be unambiguously proven in a mammal, and (c) high sensitivity to small changes in polarity , rather than in intensity, of MF was identified as biologically meaningful. Our findings open new horizons in magnetoreception research. Since the MF is calm in only about 20% of the daylight period, our findings might provide an explanation why many magnetoreception experiments were hardly replicable and why directional values of records in diverse observations are frequently compromised by scatter. 

The full paper is available online.

If verified, this is a fascinating result from a couple of perspectives.  First, of course, is the surprise discovery of magnetic field sensitivity in dogs.  Then there's the author's hypothesis that MF variability is the reason other attempts to detect this ability have failed – which opens the possibility that the ability to detect magnetic fields is far more common than we'd thought.  Possibly it even provides the mechanism that allows (some :) people to “know” their position and direction.  And I'm certain that Dave Barry is intrigued by the prominent role of peeing and pooping in the study...