Part of being a dog owner is learning the ins and outs of your dog's bizarre behavior.
Why do they only play with chew toys in primary colors? Why do they ask to be let outside, then whine to come back in seconds later?
But the most mysterious habit of all is the spin many owners notice their dogs do before going to the bathroom. What's up with that?
Experts actually have two theories to explain this common behavior. One is pretty mundane, while the other is downright bizarre.
The Trampling Theory
You might have noticed that dogs do a very similar 360° spin before lying down to sleep. Many experts think these behaviors are linked.
In the wild, dogs would be smart to do a quick sweep for predators, either before going to the washroom or lying down to sleep.
Circling in place also flattens the grass below the dog, making a comfortable "bed" for them to lie in.
Some research seems to back up this theory, because dogs will spin more often on uneven surfaces, which need trampling.
While going #2, a flat area is also more comfortable for the dog, since poop is less likely to catch in the grass and get stuck in their fur.
Finally, the spin makes it very obvious to other dogs that this is your dog's spot, for a number of reasons.
First, the spin is very visible, and leaves behind a flattened area for other dogs to recognize. But a flat space also helps scent-marking pheromones in your dog's poop and pee spread out, claiming their space.
The Compass Theory
While the trampling explanation seems to explain the spin quite nicely, it never stuck with Czech researcher Hynek Burda.
He pointed out that dogs can sniff out predators, and hear them coming, while standing in place, so the spin seemed unnecessary.
In Frontiers in Zoology, he offered his own explanation for the strange habit: dogs are lining themselves up with the earth's magnetic fields.
It sounds absurd, but it's not. Researchers already believe animals like birds and cows have a sense called magnetoreception, which lets them use magnetic fields to sense direction.
Some experts even believe our own evolutionary ancestors had that ability.
Burda suggests dogs have some type of internal compass, and his team spent two years watching dogs do their business to prove it.
They discovered that dogs almost always face north or south when doing their business.
And during times when the magnetic pull was less stable, dogs were less picky about their direction, which suggests Burda's theory is right.
But what's the connection between direction and poop? An obvious answer is that dogs facing north or south never have the sun in their eyes.
Dogs also pee and poop to mark their territory. So it would probably be helpful if they had a strong sense of exactly where they were doing their business.
Bet you didn't realize your pooch was so smart, right?
[H/T: Reader's Digest]