Evolution

• Because dogs evolved as pack animals, the domestic dogs' ancestors could not survive alone. Wild dogs that were hunting for food across great distances had to return to their pack or die. The canine's innate sense of direction evolved because it helped to ensure the species' long-term survival. Wild dogs with the greatest talent for finding their way home would have had the greatest chance of survival, and these genes may have been passed on, according to Animal behaviorist Dr. Nicholas Dodman.
  
  

Mental Maps

• Dogs, like people, combine observation with mental map-making to get their bearings and retrace their steps. They observe their surroundings and memorize landmarks such as trees, fields, or even a friendly neighbor's house.
  
  

Natural Senses

• Dogs' well-developed sense of smell, combined with keen hearing, are useful allies when it comes to finding their way home. A dog might, for example, be guided by the sound of a river and the scents from a farmyard.
  
  

Long-Distance Dogs

• The canine's use of its natural senses of sight, sound and scent to find its way home doesn't explain its apparent supernatural ability to travel home across vast distances. There are well-documented cases of dogs that traveled thousands of miles to return to their home and loved ones. The writer Victor Hugo's pet poodle, Baron, traveled from Paris to Russia, a distance of almost 2,000 miles, in less than a month to be reunited with his literary master. Hugo gave Baron to a friend in 1877 because the dog was excessively demanding and interfered with his writing, but the two were never again parted after Baron's return. Scientists are unsure why some dogs possess this ability, but, according to Dodman, it's possible that, like birds, they may use magnetic fields and the sun to find their way home.