It is thought there is a protein in their eyes that causes a shadow when they are in the correct alignment with the earth’s magnetic field.
When they align to the north, they successfully pounce on their prey 74% of the time. If they align in any other direction, they are only successful 18% of the time.
So while other animals use the earth’s magnetic field to judge distance, foxes use it to judge distance, depth and direction. Pretty darn cool. A true superpower.
https://championsforwildlife.org/nature-journal/blogs/discover-how-the-amazing-fox-uses-earths-magnetic-field.html#%3A%7E%3Atext=It+is+thought+there+is%2Csuccessful+18%25+of+the+time.
I had no idea. That's so cool! Thanks for sharing that tidbit, made my day :D