I think most dogs bark when they see other dogs unless they are both outside of their territory. I've noticed that spitz dogs don't bark as much as other dogs.

This morning, we saw one of the tom cats of the neighborhood. He stayed put, while my dog talked to him, but when she got closer (she's very eager), he got up and walked away, marking his territory on the way. It was like he said, "I'm not scared of you, just because you're bigger. I just wanted to leave for other reasons, and here, look, this is MY place."