As a search and rescue volunteer, I have had a number of fascinating experiences with trained scent dogs. I thought scent dogs only really worked in the movies, but watching them work to find humans lost in the woods was an eye-opening experience.

I watched a dog in training follow a 1km scent trail that was several hours old. This dog was not even fully trained for the activity and followed every footstep to the subject.

They really do navigate with their nose, as well. I was the subject for another exercise, and I watched a dog look almost straight at me, not see me, then pick up my scent and follow their nose straight to me.