A dog's ability to find its way home can sometimes seem supernatural, but a new study from the Czech Republic suggests it's the result of their sensitivity to the Earth's geomagnetic field.
A group of researchers from the Czech University of Life Sciences, Virginia Tech, and elsewhere, tracked the navigation abilities of 27 different dogs from 10 breeds over the course of three years.
They attached a GPS collar and camera mount to each dog and periodically would release from their leash during walks in a forest hunting area.
After being released, each dog ran deeper into the woods, and after a certain distance they were called back to their owners, at which point they all conducted what the researchers describe as a 'compass run.'This entailed a short dash of around 65 feet that closely tracked with the Earth's north-south geomagnetic axis, which 'It is unlikely that the direct involvement of visual, olfactory or celestial cues can explain the highly stereotyped and consistent ~north south alignment of the compass run,' the researchers explained in a summary of their findings in the online journal eLife.
'For example, the forested habitat and dense vegetation of the study sites make visual piloting unreliable and, in many cases, not possible.'
After this initial compass run, dogs worked their way back relying on two particular forms of navigation.
Around 59% of the dogs switched to scent-based navigation, what the researchers called 'tracking,' while another 32% relied on physical landmarks and other visual information, which the researchers described as 'scouting.
Eight per cent of the dogs used a mix of tracking and scouting behaviors to make their way back through the forest to their owners.
The walks took place over a three-year period between 2014 and 2017 and were conducted in a variety of different weather conditions, none of which appeared to have any influence on the dog's behavior.
Past research has shown dogs also mark their territory and defecate in alignment with the north-south geomagnetic axis.
One possible explanation for the sensitivity to geomagnetic fields could be a protein called cryptochrome-1, which has been shown to be influenced by the Earth's magnetic fields.
A number of other animals have similar sensitivity to the Earth's magnetic field, including blind mole-rats, whales, and even bees.
The researchers hope that future research could clarify more about how these sensitivities affect navigation, potentially by providing a 'universal reference frame.'researchers believed helped the dogs orient themselves for the return trip.