About 15 years ago, I was taking Lady out for an 11 pm walk, and we were strolling out of the carport. Suddenly, Lady turned and dragged me back to the door.
As I opened the door, I smelled it: a skunk! Lady's nose knew before mine did.
Another time, we were walking down the lane late, and Lady suddenly stopped. She turned and hurried us back to the house. I didn't smell a skunk, but she had detected something.