Dogs may line up north-south when they poop, but only when Earth’s magnetic field is calm. That’s what a 2013 study of 70 dogs found: it’s a tendency in the data, not a rule your dog follows every time.
If you’ve ever watched your dog spin in circles before doing its business, you’ve probably wondered what it’s looking for. Here Mundo Mascotita explains the dog poop compass study, what it really showed and what scientists still don’t know.
The 2013 study of 70 dogs
In 2013, a team of Czech and German researchers led by Vlastimil Hart published a study in the journal Frontiers in Zoology with an unusual question: do dogs care about compass direction when they relieve themselves?
Over two years, they and the dogs’ owners recorded:
- 70 dogs from 37 breeds.
- 1,893 defecations and 5,582 urinations.
- The direction of the dog’s body axis each time, measured with a compass, in open areas without walls or fences that could influence the direction.
It sounds funny, and the study did win an Ig Nobel Prize, which honors research that “first makes people laugh, and then makes them think.” But the method was serious and the paper is free to read.
North-south alignment explained
When the researchers looked at all the data together, the result was weak and scattered. The interesting pattern appeared when they sorted the records by the state of Earth’s magnetic field at the time.
On days when the magnetic field was calm, dogs tended to poop with their body aligned on the north-south axis, and tended to avoid the east-west axis. They didn’t all face north: the alignment was along the axis, so a dog facing south counts too.
The authors concluded that dogs seem to be sensitive to small variations in the magnetic field. Other animals are known to sense it as well, including migratory birds, sea turtles and some mammals.
Only when the magnetic field is calm
Earth’s magnetic field is not perfectly stable. Activity from the Sun can cause small changes, and occasionally larger disturbances called geomagnetic storms.
In the study, the north-south preference showed up only during periods when the magnetic field was stable. When the field was changing, the dogs’ orientation looked random. That’s an important detail: the effect is subtle and depends on conditions that you can’t see from your backyard.
Why your dog spins before pooping
The study didn’t prove why dogs turn in circles before they go, and it’s likely that several reasons mix together:
- Finding the right spot. Dogs sniff the ground for smells left by other animals.
- Safety. Pooping is a vulnerable moment. Turning gives a dog a look at its surroundings.
- Flattening the ground. In grass or snow, turning can make a more comfortable spot.
- Orientation. According to the 2013 data, alignment with the magnetic field may be one of the factors when conditions are calm.
If your dog spins a lot more than usual, strains, cries or has diarrhea or blood in the stool, that is a health question, not a compass question. Call your veterinarian.
What we still don’t know
This study is a fascinating first step, but it has clear limits:
- It shows a tendency, not a rule. Many individual dogs did not line up, and the overall data without sorting was weak.
- It doesn’t explain how. The researchers couldn’t say which sense or organ lets dogs detect the magnetic field.
- Other explanations weren’t fully ruled out. Some commentators asked whether factors like the position of the Sun could play a role.
- Breed differences couldn’t be studied. There were too few dogs per breed.
So enjoy the fact, and don’t worry if your dog poops facing east. It’s not broken. The magnetic field might have been busy that day, or your dog simply had other priorities.
FAQ
Do dogs really poop facing north?
Not exactly. A 2013 study found that dogs tended to align their body on the north-south axis when pooping, but only during periods when Earth’s magnetic field was calm. Facing south counts too, and many dogs didn’t follow the pattern.
Why do dogs spin before they poop?
Probably for several reasons: finding a spot by smell, checking the surroundings for safety and flattening grass or snow. The magnetic field study suggests orientation may also play a role when the field is stable.
How did scientists measure this?
Owners and researchers recorded the body direction of 70 dogs with a compass over two years, in open areas. They logged 1,893 defecations and 5,582 urinations, then compared the directions with data on the magnetic field.
Can dogs sense the magnetic field?
The 2013 study suggests dogs are sensitive to small changes in the magnetic field, as several other animals are. But scientists don’t yet know how dogs would detect it, and more research is needed.
Should I worry if my dog spins a lot before pooping?
Some spinning is normal. Call your vet if it’s new or excessive, or if your dog strains, cries, has diarrhea, blood in the stool or seems uncomfortable, since that may point to a digestive or anal gland problem.
This guide is part of Mundo Mascotita in English. Read also: Do dogs dream? and What does tail wagging mean?
Sources
- Hart, V., Nováková, P., Malkemper, E. P. et al. (2013). Dogs are sensitive to small variations of the Earth’s magnetic field. Frontiers in Zoology, 10, 80. Full text (PubMed Central).
