Many dogs are uncomfortable around unfamiliar people. By the time most people call me for help, the dog hears, sees, or smells someone coming - maybe to their home or yard, maybe past their car, or just out on a walk, and erupts into barking, lunging, and growling. This behavior is designed to drive the stranger further away. Some dogs are "fine" until people are much closer to them, invading their space by leaning, reaching, or touching them to greet the dog or when visiting the vet or the groomer. If a dog is pushed too far too many times, they may escalate to using their teeth to end perceived conflicts with strangers.
The early signs that a dog is uncomfortable with strangers may be too subtle for most people to read. Dogs might simply avoid other people as puppies by retreating, hiding behind a familiar person, or averting their gaze, and the body may be crouched with a tail drooping or tucking. You might notice the white of their eye becomes visible when this happens. People often pick up or move puppies to allow strangers to handle them. From a human perspective, they are showing the pup that it's not scary. I like to ask clients to imagine a scenario where someone holds them still for something they find scary to touch them, like a bat, snake, rat, or spider. Even if nothing bad happened, most people would not enjoy that interaction.
Why would a puppy or dog be uncomfortable with strangers? First, they may have been born with a genetic predisposition toward anxiety, and certain breeds may tend to be aloof with strangers or created at some point to guard flocks or homes. They may also have lacked adequate positive experiences during socialization between the ages of 3-14 weeks, or they may have had one or more negative experiences with strangers. It's important to realize the puppy or dog decides what's negative, not us, so things like picking up, getting shots, and being bathed can all seem really uncomfortable and scary to a young pup. You can avoid this by using cooperative care techniques and working with vets and groomers who have taken fear-free and low-stress handling classes.
When people don't read a puppy's signs, the puppy may need to escalate. I tend to see escalation begin at around 8-9 months of age, and again around 18 months, and then again around age 3 years. This might include tall postures, tail flagging, direct stares, lip curls, bared teeth, and growling. Then the dog may escalate to lunging and snarling, muzzle punches or snapping, and finally to biting with decreasing levels of inhibition.
If your dog has escalated to obvious signs of trying to drive strangers away, it's important to work with a qualified professional like a veterinary behaviorist in partnership with a CDBC or CAAB. They should help you learn to recognize body language, manage the environment to prevent bites and keep strangers safe, and create protocols for helping your dog feel more comfortable around visitors. A veterinary behaviorist may also suggest the use of medication to help your dog think and decide in difficult situations instead of panicking and reacting.
Management
Create a safe haven at your home. Your dog should have a space away from the entry. I prefer to have 2 doors or a gate plus a door between the dog and the visitor, except in cases where dogs have separation anxiety. This may be in an en suite bathroom or in a closet in a bedroom, for example. We provide a new, interesting, edible chew, a comfortable bed, and masking noise (like brown noise plus rock music or TV.)
Create space on walks by wearing a vest that requests space. Etsy has lots of good ones for dogs and humans, and I find the ones for humans have the best visibility. You may also want to check out using a head halter or muzzle. It takes time to train a dog to wear either of those happily, and you can look at Muzzle Up Project online for video resources about that. Have backups on your equipment in case of failure. I like to attach a hands-free leash to one harness clip and then run a carabiner between the second harness clip ring and a martingale collar, for instance.
If your car can accommodate a crate, you can toss a light sheet over the crate to block views. If not, you can teach your dog to wear a Thundercap to obscure views slightly, too. Do your best to choose routes where you avoid areas with lots of pedestrians and park further away from shopping centers where fewer people are nearby.
Protocols
Meeting outside: Your dog may feel better about seeing visitors outside initially, and you'll pair the noticing of the visitor by your dog with you feeding a steady stream of high-value food, like diced chicken breast. If you have a fenced yard, you and your dog can be in the yard with your visitor outside the fence, but if not, meet outside the home, a little way down the street if possible, with some distance between you, enough that your dog can notice the visitor but not seem stressed. Then take a walk with some distance between you so you are parallel, maybe on opposite sides of a street or yard. Your dog should look fairly relaxed. Then, your visitor can enter the home and sit down, and you follow at a distance. Keep your dog on a leash and at a safe distance until you are sure your dog is comfortable. Your dog may be less comfortable if your visitors stand, lean, reach, make eye contact, gesture, or walk, so keep enough space to handle those unexpected moments, called sudden environmental contrast or change (SEC for short.) Ask your visitor to ignore the dog unless the dog is actively soliciting attention with a loose, wiggly body.
Meeting while seated: Some dogs live in such a busy environment that meeting outside isn't a good option. Have your visitor send you an ETA, and confine your dog in the safe haven a few minutes prior to arrival. Ask the visitor to text on arrival instead of knocking or ringing a doorbell, and let them in quietly. Those sounds likely have too much history predicting strangers to be used, and doorways are usually stressful for dogs who are wary of strangers. Have them take a seat, then go get your dog. I find that people do best on bar stools as opposed to low chairs if that's an option. Get your dog with a leash, and pause as soon as your dog notices the visitor or at the entrance of the room if your dog gets there without noticing yet. Then, feed a steady stream of high-value food, like diced chicken breast. Keep your dog either behind a gate to that room or on a leash near you and at a safe distance until you are sure your dog is comfortable with the visitor. Your dog may be less comfortable if your visitors stand, lean, reach, make eye contact, gesture, or walk, so keep enough space to handle those unexpected moments, called sudden environmental contrast or change (SEC for short.) Ask your visitor to ignore the dog unless the dog is actively soliciting attention with a loose, wiggly body.
Set up happy visits at the vet or groomer, where you go to the parking lot, walk around, give your dog treats, and leave. If that's easy, go inside the lobby, feed treats, and leave. Vets often have times of day, like during surgery hours, when the lobby will be quiet. Groomers may not have as many quiet times, so be sure to ask what's best wherever you're visiting.
Things to Avoid
Don't assume your dog will remember the visitor the next time they arrive. Not all dogs remember from visit to visit, and some dogs take a few moments to recognize someone's scent. Always keep a safe buffer between your dog and people at the entrance of your home and yard.
Don't have the visitor feed the dog. You may inadvertently put the dog in a position of conflict to decide between their worry about the stranger and their desire for the food.
Be extra cautious with people who tell you they are great with dogs and dogs love them. They tend to be overconfident, leaning and reaching hands to dogs. That's the last thing they should do. Ignoring the dog is a better plan.
If the dog sniffs the stranger, that is not a sign of comfort - it's just a sniff. The visitor should not reach for the dog at that moment. I prefer sniffing through a fence or gate when possible to avoid accidents.
Remember, you are your dog's advocate. By making proactive decisions and communicating with strangers exactly what to do and not to do, you can help keep your dog feeling as safe as possible.