The next time you’re lost in the wilderness, trying to figure out which way is north, forget about moss growing on the side of a tree. Just pay attention to how your dog poops. He’s a regular canine crap compass.

Okay, that is a vast oversimplification of two years’ worth of study by a group of German and Czech researchers, but it illustrates how much we’re still learning about the mysteries of man’s best friend. It turns out that when he squats to defecate, your dog may be communing with the unseen lines of magnetism that girdle our planet.

That, at least, is the gist of an article published late last year in the journal Frontiers in Zoology titled, “Dogs are sensitive to small variations of the Earth’s magnetic field.”

The basic finding was this: When a dog poops, it’s likely to align its spine along a north- south axis.

Freaky, huh? And yet to those of us who own dogs, it doesn’t come as a complete surprise. We spend a lot of time watching our pets, and we know that there’s definitely something going on. It’s why when we walk our dogs, plastic bag in hand, we often can be heard muttering, “Come on. Poop already. What are you waiting for?”

They may be waiting for their inner GPS to recalculate.

Fascinated by these findings, I e-mailed Hynek Burda, a zoologist at the University of Duisburg-Essen in Germany and a co-author of the article. He said it’s been known that some animals — red and roe deer; cattle — show behavior that appears “magnetoreceptive,” that is, sensitive to magnetic fields. His group decided to see if that was true with dogs, too.

Wrote Hynek: “There are anecdotal reports of their extraordinary homing abilities (just remember Lassie come home) and there is also a well-known common behavior — circling before excretion or before sleeping — which is enigmatic and for which there is no scientific explanation.”

To find out, volunteers enlisted 70 different dogs. They observed 1,893 instances of defecation and 5,582 instances of urination. They made sure the dogs were off-leash, out of their back yards, and away from power lines and buildings.

Now, the Earth’s magnetic field is not stable. While its fluctuations aren’t enough to set a compass needle spinning, they are measurable. What the researchers found was that in periods of magnetic stability, dogs were more likely to align themselves along a north-south axis while doing their business, with a preference for facing north.

You are possibly wondering why a dog would do such a thing. The authors aren’t sure. Nor do they know whether the dogs do it consciously — somehow detecting the specifics of the magnetic field — or whether they are reacting on a more primal level. Does a dog just feel better when aligned in a certain direction?

Hynek thinks the magnetic ability might be connected with territory marking. “A dog who is outdoors, out of his backyard, marks his home range or an unfamiliar region,” he wrote. “Perhaps you have also noticed that the dog knows well (and can remember) not only where he hid a bone but also where are his marking cornerstones. He has a mental map of his home range or creates such a map whenever in an unfamiliar region. Our hypothesis is that he uses these short stops to store the location (‘coordinates’) of marking cornerstones in his memory. Doing so, and/or calibrating his magnetic compass, is probably easier for him when being aligned with the magnetic field.”

Hynek doesn’t own a dog. He borrowed a neighbor’s dog — an 11-year-old bearded collie named Freda — for the study. Other dog breeds included Airedales, beagles, terriers and dachshunds — lots and lots of dachshunds. (There were a few mutts, too.)

Research continues. Hynek and his team are soliciting volunteers for a worldwide project to collect even more data.

“We need to analyze behavior of many more dogs to be able to find out whether there is some effect of breed, age, sex, diseases, other sensory capabilities,” he wrote. “Blind and deaf dogs are welcome to participate in the project.”

Just go to to get instructions on how to take part and to download a spreadsheet.

These findings have given me newfound respect for my black Lab, Charlie, whom I had pretty much considered an idiot. Who knew he was so talented?

Charlie spends a lot of time licking himself. Now I’m waiting for scientists to tell me he’s actually predicting sunspot activity or barometric pressure.

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