Scientists Believe Dogs Are Using Earth’s North-South Magnetic Fields as an Internal Compass to Navigate, Similar to Migratory Species

Story by Rebecca West
We’ve all heard the stories. Pets finding their way cross-country, inexplicably showing up thousands of miles away years later. They’re usually lost before or during a move. Sometimes they’ve been left behind to live with friends or family and ran off after the fact. Or they’ve become separated during a trip or vacation. It defies logic, but there it is: against all odds they’re back. While dogs have a remarkable sense of smell, that certainly can’t be all that’s at play here. Their humans didn’t walk from Maine to Iowa or Florida to Montana. They drove off in cars. How do you track that, even if you’re a bloodhound?
It’s seemed very unlikely that could be the sole explanation, but up to this point, no one had proffered any proven hypotheses to definitively explain the uncanny ability. While there may not be any one specific reason for it, another part of the puzzle may be falling into place. According to a recent study, it’s quite possible dogs are able to use the Earth’s magnetic field to orient themselves. The ability, known as magnetoreception, allows other creatures, such as whales, dolphins, sea turtles, and birds, to use this sixth sense for plotting the course of their annual migrations. It’s called homing behavior.
Homing, defined as the ability to return to a known location (breeding grounds, shelter sites, etc.) after displacement, has been exhibited in a diverse range of vertebrates that rely on a multitude of cues for navigating. They can include visual, scent, acoustic, celestial, magnetic, and idiothetic. Idiothetic, or self-proposition, is used in navigation models for describing the use of self-motion cues, rather than allothetic or external cues, which are forms of sensory information derived from the surrounding environment.
Up to this point, studies characterizing the navigational strategies of homing behavior in non-migratory species — particularly free-ranging mammals — have been scant. One of the earliest examples dates to 1920 when scientists attempted to decipher the mystery after using canine military couriers displaced to unfamiliar sites while delivering messages during WWI. Since then, there hasn’t been a whole lot published on the subject of any real consequence. Because our understanding of large-scale navigation and homing remains incomplete, designing tests has proven difficult but not impossible.
“The magnetic field may provide dogs with a ‘universal’ reference frame, which is essential for long-distance navigation, and arguably, the most important component that is ‘missing’ from our current understanding of mammalian special behavior and cognition,” the authors of the new study wrote.
To test their theories, researchers from Czechoslovakia and the U.S. utilized GPS and video cams to study the navigational styles of 27 canines from 10 breeds. In total, 622 trials were conducted at 62 locations consisting of forested hunting grounds. Based on the records, they determined turning points, thus dividing the excursions into outbound and inbound tracks. Undertaken between 2014 and 2017, they chose hunting breeds bred to locate prey in dense woodlands and thick brush and then navigate their way back to the start or release point.
Researchers discovered that during two-thirds of the excursions, the dogs typically retraced their steps back by simply using smell. But in a third of the expeditions, the dogs took a different route back. This is where it gets really interesting. Of the dogs diverging from the scent method, most of them began by running for 65 feet along Earth’s north-south axis — even if the direction of their destination differed from this line. This prepping or “compass run” is thought to aid in determining where magnetic north and south lie and where the animal is in relation to those points. In other words, they needed to get their bearings before heading back.
“This run is instrumental for bringing the mental map into register with the magnetic compass and to establish the heading of the animal,” the authors wrote.
In 399 cases (59.4 %), dogs “homed” by following their initial outbound track (scenting or tracking strategy), and in 223 cases (33.2 %), dogs homed using a novel return route (scouting strategy). In 50 cases (8.0 %), it was determined dogs combined both strategies during a single return. It was ultimately revealed that scouting dogs were faster in their returns than those using tracking. Sex, breed, and sun position did not influence the outcomes.
In other canine magnetoreception mysteries, after observing 37 breeds over a two-year period some 10 years ago, 12 Czech and German scientists came to the conclusion that dogs eliminate waste in alignment with the Earth’s magnetic field. They studied a total of 1,893 defecations and 5,582 urinations while recording the orientation of the animals’ spines with a compass to reach their conclusions. No explanation was given as to why they relieve themselves in a north-south direction, but scientists have known for years that several species spontaneously align with the Earth’s magnetic field when engaging in certain behaviors.
These and other conundrums will undoubtedly be fleshed out in the coming years as we learn more about our canine companions and gain a better understanding of the world around us. In the meantime, it’s pretty cool just knowing how evolved humankind’s best friend really is.



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