Dogs instincts are infallible....
When I was married (a century ago..
), we had 2 chows. I was a brand new father and a rookie cop. 1 night both my chows awakened, took up an "attack stance" at the front door, with heads lowered, and giving that very soft but deadly gutteral growl they use when danger is near. When I didn't immediately respond, the male, Buddy, came and slapped my face with his giant paw..he was huge...
I awakened somewhat annoyed and he quickly ran to the bedroom door, looking back to make sure I was following him. It was then that I heard Yonah, my female, growling and giving soft whisper like barks. She had not moved at all. Then I realized what was going on. So I returned to my bedroom and picked up my duty weapon.
I then looked outside the front windows carefully, keeping all interior lights off. I saw 2 bodies in my front yard...kind of just standing there...feet away from my front door. I watched and listened intently. I heard girls voices, laughing, and observed them kind of stumbling over each other.
Turns out they were neighbors teen-aged daughters, who were walking home from a party, drunk, and were lost. That was only 1 of many instances where those 2 dogs kept me and my family safe. Everyone in the nieghborhood knew about those 2 dogs. Probably why when a rash of home invasions occurred mine was never touched...