If you're a dog owner, you've probably noticed that some dogs will spin around a few times in a circle before settling in to relieve themselves. Ever wonder why?
Turns out it's because they're trying to align with the Earth's magnetic field, according to new research.
"Dogs preferred to excrete with the body being aligned along the north-south axis under calm MF [magnetic field] conditions," according to the findings by researchers in the Czech Republic and Germany. "This directional behavior was abolished under Unstable MF." The results were published in the journal Frontiers in Zoology.
To test their theory, scientists had 70 dogs, from 37 breeds, observed over a two-year span. The orientation of the dogs during defecation was cataloged 1,893 times and during urination 5,582 times.
The report said the planet's magnetic field is "calm" for only about 20 percent of the time during the daytime. "Our findings might provide an explanation why many magnetoreception experiments were hardly replicable and why directional values of records in diverse observations are frequently compromised by scatter," the researchers said.
In the case of the dogs, the researchers contended that they weren't affected by human voice commands or facial expressions as might be a risk with other studies.
"This is certainly not a confounder in our study because the dogs do not have to fulfill a certain task, but perform everyday routine behavior. The study was truly blind. Although the observers were acquainted with our previous studies on magnetic alignment in animals and could have consciously or unconsciously biased the results, no one, not even the coordinators of the study, hypothesized that expression of alignment could have been affected by the geomagnetic situation, and particularly by such subtle changes of the magnetic declination," the study said.
Additionally, the researchers ruled out the role the sun might play. "The argument that the dogs might orient with regard to sun position so that they turn with their back to the sun in order to avoid dazzling by sunshine during such a sensitive and vulnerable act as excretion can be questioned. This argument is not plausible for urine marking, which is a brief act."
Ultimately, the researchers did say it remains "enigmatic" why the dogs aligned, that is, whether they were aware of some sensory effect the magnetic field had, leading them to align, or if they simply "felt" better in particular orientation. "Our analysis of the raw data indicates that dogs not only prefer [north-south] direction, but at the same time they also avoid [east-west] direction."
Past research has focused on whether birds and some land animals are influenced into behaviors, such as flight paths or standing in a certain direction, based on the magnetic field. In one instance, research found that cows appeared to line up with the field. The scientists behind those findings included Hynek Burda of the University of Duisburg-Essen, one of the researchers in the dog study. However, a different group's attempt to repeat the cow-orientation findings were unsuccessful at proving the influence of the magnetic field.