I read about this in the newspaper. Someone mention about stray dog being a protector for our friendly neighbourhood. This was a very intersting thought that I have never think about. I always think that the dog in the house is kind of like a protecteor but didn't know that stray dog did the same job as the well kept dog.
Dog protect their own territory from outsider. They pee to show that they owned the territory. I think it helps them to recognize who is staying there and who is not. Stray dog don't really attack the neighbourhood that is staying there. Often they bark at stranger that passby.
So never despise the power of a stray dog, though I have the experience of being chase by a stray dog. Bad experience but it should be changed from now. Dog is always a good helper of human.