It’s a happy day when a lost dog finds its way home, but how does it get back? A New York Times article offers two explanations. One is that a dogs’ hypersensitive sense of smell allows them to create a map of scents around their neighborhood, using gardens or grocery stores and human aroma as markers.

In addition, they may be sensitive to magnetic orientation. One study of dozens of canines observed that dogs tend to adopt a north-south orientation when they 'go potty', but that preference vanished when the magnetic field around them was disturbed.