There is research that answers questions nobody asked. And then there is this one, published in 2013 in the journal Frontiers in Zoology: dogs prefer to align themselves along the north-south axis of the Earth’s magnetic field when they relieve themselves.
This was not a joke, it was two years of work
A Czech-German research team observed 70 dogs from 37 breeds and documented 1,893 droppings and more than 5,000 urination breaks. Someone had to count all that. The result: when the magnetic field was calm, the dogs lined up along a north-south direction significantly often. When the field was unsettled, the effect disappeared.
Why do they do it?
Short answer: nobody knows. The assumption is that dogs can perceive the magnetic field, much like migratory birds or foxes, which also prefer to aim their mouse pounces towards the north-east. What a dachshund in a city park needs a compass for remains open.
What you can do with this
Honestly: nothing. But on your next walk you will look, we promise you that. And when your dog turns in a circle three times before committing, you now know: he may be calibrating.
Source: Hart, V. et al., “Dogs are sensitive to small variations of the Earth’s magnetic field”, Frontiers in Zoology 10, 80 (2013).