- As the dogs navigate, they appear to be using Earth’s magnetic fields.
- 170 dogs head north and south while tracing shortcuts back to their people.
- Dogs join the growing number of magnetically sensitive animals.
It has been known for some time that some animals (migratory birds, mole rats, and locusts among them) use Earth’s magnetic fields to navigate. There is even some evidence to suggest that we are, too. In 2013, zoologist Hynek Burda discovered that dogs tend to defecate and urinate along a north-south axis, although at least some dogs (including our own Lulu) disagree. New research indicates that dogs also target Earth’s magnetic field as they invent shortcuts to get from one place to another.
The research comes from Kateřina Benediktová of the Czech University of Life Sciences in Prague (Burda is her PhD advisor) and is published on eLife.
Guessing the secrets of canine boaters
That dogs have excellent sailing talents is nothing new. The study is reminiscent of “messenger dogs” that were relied on during World War I to transport sensitive communications back and forth across battle lines. Also, of course, hunting dogs, or “olfactory hounds,” have long exhibited the ability to return to their owners’ positions, and previous studies have shown that they often design new return routes, rather than simply retrace your steps. How they do this has been a bit of a mystery, as the study notes: “Dogs often headed using new routes and / or shortcuts, ruling out route reversal strategies and making olfactory tracking and visual piloting unlikely.” .
In trying to discover how dogs do what they do, researchers have divided their methods into three possible ways:
- Tracking: Following your own scent trail to its point of origin
- exploration: looking for a new shorter path back to its point of origin
- visual piloting: using landmarks to find your way back
Benediktová’s investigation began when he placed video cameras and GPS trackers on four dogs, took them out into the woods and released them. As expected, they took off in search of an interesting scent. All the dogs finally returned. She mapped the collected GPS data, viewing both tracking and scanning executions.
However, when he showed Burda his maps, he noticed something else. Just before returning, the dogs did something strange: they ran approximately 20 meters along a precise north-south axis, as if orienting themselves, before returning to Benediktová. Without some form of magnetic sensitivity, this would not be possible.
Image source: Benediktová, et al.
Test the theory
A sample of four dogs is not definitive, so the student and advisor conducted a larger study of 27 dogs that were taken on several hundred scouting trips over the course of three years. The dogs were generally taken to places they were unfamiliar with, and the researchers avoided hitting the canines with any navigational trail, including avoiding situations where the wind could carry their scent toward the dogs. Investigators also went into hiding after releasing their charges to make sure they weren’t visible to the puppies.
In the end, the researchers documented 223 scouting runs in which the dogs averaged a return to their point of origin of about 1.1 kilometers (about 0.7 miles).
In 170 of these runs, the dogs repeated the behavior of the smallest sample, running about 20 meters along a north-south axis. Just as intriguing, it was these dogs who found the fastest and most direct route back. “I am really impressed with the data,” biologist Catherine Lohmann of the University of North Carolina, Chapel Hill, who was not involved in the study, told Science.
Burda finds the dogs’ apparent confidence in their north-south jog quite compelling: “It is the most plausible explanation.”
Test the theory
Commenting on the research, canine behaviorist Adam Miklósi of Eötvös Loránd University tells Science: “The problem is that to 100% test the magnetic sense, or any sense, you have to exclude everyone else.”
Given the difficulties in doing so, Benediktová and Burda intend to test their hypothesis from the other direction, to see if they can confuse the magnetoreception of the dogs by putting magnets on their collars and repeating the tests, if they no longer do their little north jog- South, a dependence on Earth’s magnetic field would look even more likely.
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