Do dogs have a secret compass?
Dogs are sensitive to small variations of the Earth’s magnetic field
When the magnetic field is calm, dogs like to face north or south during their walkies business.
Ig Nobel 2014
Researchers watched 70 dogs on thousands of walks, and recorded which way each dog was facing.
When the Earth’s magnetic field was stable, dogs lined up along the north–south axis. It suggests dogs can sense magnetic fields, a bit like birds.
Your dog has a secret built-in compass. Good dog.