Holy sh*t! Why does my dog spin around endlessly before doing his business?

When we walk our dogs, plastic bag in hand, we often can be heard muttering, “Come on. Poop already. What are you waiting for?”

People like to assume their dogs do things just to annoy them. Well, they’re wrong. While we may dream up fiendish plots to irritate those around us, dogs don’t think that way.

So, when your dog spins around in circles before pooping, it’s not to drive you crazy. It’s because they’re sensitive to the Earth’s magnetic field. Say what? Yes, you read that correctly. They may be waiting for their inner GPS to recalculate.

According to a study in the journal Frontiers in Zoology, canines choose to relieve themselves in a north-south axis. In fact, they will actively avoid pooping (or peeing) in an east-west direction.

After examining 70 dogs — made up of 37 breeds — over two years, 1,893 defecations and 5,582 urinations, the researchers found that under “calm magnetic field conditions,” dogs preferred to “excrete with the body being aligned along the north-south axis.” (Makes you wonder who drew the short straw to watch all of this.) The researchers placed the dogs in a free-roaming environment, meaning the pooches were not leashed and were away from any walls or roads that would influence linear movement.

Why do the dogs prefer the north-south axis and avoid east-west? That remains a mystery. It is unclear, according to the study, whether the dogs consciously sense the compass direction or whether they simply know on a primal level that they feel better or more comfortable on the north-south axis.

Hynek Burda, a zoologist at the University of Duisburg-Essen in Germany and a co-author of the study, thinks the magnetic ability might be connected with territory marking. When the dog relieves himself, he is marking his home range or an unfamiliar region. Each pit stop, then, can be viewed as a way to store the location (or “coordinates”) to create a mental map for himself. This is how he can find where he hid a bone, or how he can find his way home. Creating these coordinates is probably easier for him when he’s aligned with the magnetic field.

The study’s findings is further proof that many animals are able to sense the Earth’s magnetic field and adjust their behavior accordingly. Scientists hope that this sparks further interest in research of magnetic fields on living organisms and the magnetic fields that living organisms produce.

Perhaps the next time you’re lost in the wilderness, trying to figure out which way is north, you can forget about moss growing on the side of a tree and just wait for your dog to poop. After all, he’s apparently a canine crap compass.