Certain things set dogs off. Our obedience instructor years ago explained to a room full of puppy owners that, most likely, there would be certain things that would trigger odd or fearful reactions in our dogs. For some it may be umbrellas, for others it may be wheelchairs or strollers or any other contraption they haven't encountered before. For Baxter, it has turned out to be two things: 1) backpacks and 2) people who smell like cats.
1) The Mysteries of the Backpack: Baxter is great with children. He approaches them quietly and gently and waits for them to reach out their hands to pet him. He doesn't jump or slobber or gush in any way. He will tolerate amazing things from babies -- a toddler once ambled up to him on a hiking trail, giggled, grabbed him by the nostrils and held on with a vicelike grip. He just stood there looking back at us like "um, is somebody going to get me out of this?" My infant neice did the same thing. He gave her a wide berth after that, but it hasn't stopped him from walking up to other babies and letting the same thing happen again. But if a child wearing a backpack tries to approach Baxter, he usually freaks out. His little tail is pressed firmly against his bum and he starts backing up and making a little "voof" sound under his breath. I can see the whites of his eyes. If the backpack-wearer continues to approach, Bax will run behind me and start barking. If the exact same child had approached him without the backpack on, he probably would have been greeted cheerfully. I don't know if it's the Quasimodo-like change in profile that throws him or if he had some bad experience with a backpack in his early life (certainly not with us), but it never fails to upset him. Oddly enough, we can go hiking with backpacks on and he's not phased at all. He knows the biscuits are in there. And he even has his own backpack and seems to enjoy wearing it. Go figure.
2) Eau de Cat: All his life Baxter has had fearful reactions to specific people who seem perfectly nice to me. I've always tended to believe that dogs are pretty good judges of character, so when Bax had a fearful reaction to a stranger, I also used to regard them with some suspicion. But now I'm thinking I can't take him too seriously, because I've realized that, probably not coincidentally, most of the people with whom he has a fear reaction have one or more cats at home. There is no such thing as a cat owner that doesn't have cat essence all over them, or at least their legs...which are right in Baxter's sniff zone. I think he gets one whiff of cat and immediately puts the person under suspicion. Are they hiding a cat somewhere under that coat? Then, if the person approaches him too quickly or reaches a hand out in an assertive way, he starts the duck and cover routine. Does he think they're somehow related to that mysterious realm of catdom and are, thus, dangerous? Or perhaps it's because these people are primarily cat people and have their own wariness or awkwardness around dogs and Baxter somehow senses that and reacts in kind?
I wish I knew what was going on in that scruffy head of his...but then again, maybe I don't!