Dogs have an enviable sense of direction. Even in a completely unfamiliar place, our pets have an uncanny way of tracking down a shortcut.

For the first time, Czech scientists have found evidence that canines can sense and navigate using Earth's weak magnetic field.

Exactly how they do this and to what extent is still unclear, but it appears this hidden sense, known as magnetoreception, really does exist in canines, just as it does in many other animals, including birds, salamanders, and frogs.

This hidden talent in our four-legged friends has long been suspected, but never actually tested in such a rigorous way.

"I'm really quite impressed with the data," biologist Catherine Lohmann who studies magnetoreception in birds and turtles and who was not involved in the study, told Science news.

While hunting, some dogs will simply retrace their steps, using scent trails to guide their way (known as tracking), but others will sometimes return to their starting point following an entirely novel route, an ability the researchers have termed as 'scouting'.

It's an interesting ability, but until now, research into how animals orient themselves and how that relates to magnetic fields has been investigated in other species in much more detail than in dogs.

A few years ago, scientists in Czechia found dogs tend to defecate and urinate along a north-to-south axis, suggesting they're able to sense Earth's magnetic field; now, a similar team from the same university has found evidence that scouting relies on this hidden sense, too.

Isolating a single sense while testing a dog is difficult, but researchers came up with a unique method. Using GPS data and video records on action cams, they watched as 27 hunting dogs from ten breeds performed 'homing' trials at 62 different forested locations.

Between 2014 and 2017, the dogs performed over 600 trials, setting out for a chase and returning to their humans.

Analysing only the scouting events, the authors found dogs that went chasing an animal's scent began their return back to their owner with a roughly 20-metre (65 ft) run along a north-south axis, regardless of where their owner was standing.

The authors called this a 'compass run', and they suspect it's a way for dogs to prime their magnetic sensors before taking off.

Because the forest was unknown to the dogs, there were no scents to track. There was also no wind carrying smells from human to dog, and the thick foliage kept the sun and the path ahead mostly obscured. On the other hand, Earth's magnetic field is a 'universal' reference frame that doesn't wane.

Taking into account all these variables, the authors argue the hunting dogs really appear to be using magnetoreception to find their way back to their owner.

Not only is this skill essential for long-distance navigation, the team thinks it's "arguably the most important component that is 'missing' from our current understanding of mammalian spatial behaviour and cognition."

Magnetoreception likely exists in a lot more species than we know. There's even a chance it's been hiding in ourselves. The molecule thought to be responsible for this hidden sixth sense in birds has recently been found in dogs, certain primates, and even bears.

The research is just beginning.

The study was published in eLife.