A new study called Dogs are sensitive to small variations of the Earth’s magnetic field  published in the Journal Frontiers in Zoology has demonstrated that dogs can sense and respond to magnetic fields. It is the first time that this has been shown in this species. Researchers found a measurable change in behavior based on the conditions of the magnetic field.
Specifically, they found that under certain conditions, dogs choose to pee and poop with their bodies aligned along the north-south axis and avoided orientation along the east-west axis. They studied 70 dogs from 37 different breeds over a two-year period, observing 1893 defecations and 5582 urinations. Observations were all made while the dogs were off leash and in open fields so that they were not influenced by walls, fences, fire hydrants or other objects.
The researchers collected data on dog directionality (and hopefully all the poop, too) and found that the way dogs face is not just a matter of chance. They ruled out such factors as time of day, angle of the sun and wind conditions. Their analysis found that the Earth’s magnetic field explained dogs’ orientation when doing their business. Interestingly, the pattern only emerged when the magnetic field was stable, which was only about 30 percent of the time. The Earth’s magnetic field can become unstable due to such factors as the variation in solar winds and the sun’s magnetic field. During such periods of instability, dogs did not show a preference for aligning themselves along the north-south axis and oriented randomly.
This research has been written about extensively in the media, possibly because any scientific research that involves potty talk is inherently amusing to journalists. Though the behavior that the researchers studied was elimination, to focus on that is to miss what’s really important about the study.
What I think is so fascinating is the revelation that dogs are able to sense the Earth’s magnetic field and that their behavior is influenced by it. It has been known for a long time that dog senses, particularly the sense of smell, mean that they are responsive to stimuli that we humans aren’t aware of, but the fact that dogs can act, in some manner, as though they have an internal compass is just as fascinating.
Previous studies have found that cattle, deer and foxes sometimes align their bodies with respect to the magnetic field. Sensitivity to the Earth’s magnetic field has previously been demonstrated in species that migrate such as birds and whales, and also in honey bees, whose navigational abilities are legendary.
Of course, people have long asserted that dogs can find their way exceptionally well, and I’ve even known people who said that it was like their dogs had internal compasses. Finding out that dogs can in fact sense the Earth’s magnetic field, just as compasses can, makes their navigational abilities perhaps more understandable, but no less extraordinary. It was in part dogs’ remarkable homing abilities that made the researchers suspect that dogs might be sensitive to the Earth’s magnetic field in the first place.
Why dogs are choosing to orient themselves in this way is the big question, and hopefully future research will pursue it. I look forward to seeing research on that subject as well as experiments investigating other canine behaviors that may be influenced by the Earth’s magnetic field.