dog aggressive with visitors to home
Behavioral Problems

Why is My Dog So Aggressive Towards Strangers?

It’s no secret that dogs make the best friend that anybody could wish for. Our tail-wagging companions offer goofy affection with no ulterior motive whatsoever, showering their owners with love for no reason other than existing.

This is all fantastic – but what are we to do with an unruly hound that isn’t quite as social with other people? Some owners find that their bundle of furry joy turns from Lassie to Cujo when confronted with visitors to the home, or when another dog crosses their path during walkies.

Assuming that your dog’s behavior is not a result of boredom or frustration due to a lack of appropriate exercise, let’s take a look at why dogs seemingly randomly become aggressive.

Are Dogs That Bark at Strangers Always Being Aggressive?

First thing’s first; it’s vital to know that not all barking is a sign of aggression. Some dogs bark out of excitement, and the dog in question believes that he or she is just being sociable and saying hello.

This will not reassure a stranger that’s on the receiving end of a canine voice box, though. A dog’s bark can still be pretty frightening to anybody that doesn’t understand that your pet would not hurt a fly, as many people will fear that an attack is set to follow.

Imagine a stranger approaching you in the street and yelling in your face, “HELLO THERE! I LOVE YOUR SHIRT! WHERE DID YOU BUY IT?” No matter how good their intentions may be, they will come across as antisocial at best!

Now, imagine that they were not speaking English when they did this. Suddenly all you know is that somebody is screaming incoherently at you, seemingly at random. This is why it’s essential to train your dog to behave his or herself appropriately around new people.

Why Dogs Bark at Strangers

Dogs often bark at strangers in the street, or when they visit the home. Many mailmen bear the psychological scars of being scolded by the real head of the family when they set foot on a property. Strangers that approach a dog may be told in no uncertain terms to stay away, even if they only intended to make a fuss through a selection of strokes and tickles. Sometimes a hound on high alert will bark at another dog or human strolling on the other side of the street.

If a dog is displaying these signs of aggression towards a stranger, it will stem from one of two causes – dominance or fear.

Popular science would have us believe that dogs are roughly as intelligent as a toddler.  This suggests that dogs operate on an instinctual, lizard-brain level. What’s more, dogs are pack animals, and they will see their human owners as the alpha of their pack. No matter how smart our tail-wagging partners in crime may be, they’ll always struggle to operate a can opener. Human owners provide the food. This means that we’ll always have the key to a canine heart!

Of course, the result of this is that our dogs are hard-wired to protect us from perceived threats. This is why dogs become dominant. They’ll do everything and anything they can to guard their territory, and by extension, the other members of their pack. A dog will grow aggressive to frighten a competitor away from their area before this interloper can help himself or herself to the precious food and resources found within.

Let’s go back to our toddler comparison…

Have you ever watched a bunch of mini-humans playing? If so, you’ll see that they’ll often guard a favored toy as though their very lives depended upon it. They’ll only reluctantly relinquish possession when an adult sternly informs them that they need to share. Dogs operate on the same basic intellectual level. This is my food! This is my house! This is my ball! These are my humans! Stay away – you can’t have them!

dog randomly becomes aggressive

Another way that dogs are comparable to small children is in their inability to communicate their feelings clearly – and the frustration this may cause. If a dog is suspicious about the motives of the mailman, for example, they will grow concerned for the safety and well-being of their pack.

Unfortunately, Fido isn’t able to tap you on the shoulder and calmly explain that the strange man wearing red is wandering around the street again, and it looks like he is checking every house for signs of weakness to break in. After all, why else would he carry that giant bag around? He must be robbing the neighbors, and we’re next in line! When a dog grows frightened, he or she instinctively starts to bark up a storm. This is your best friend’s way of warning you that danger is afoot and that you need to take action.

Ever heard the saying, “their bark is worse than their bite?”

That applies to most dogs, as they will be hoping that barking will be enough to warn their humans that some kind of shenanigans is about to unfold. If snarling and growling accompany the barking, however, you need to take immediate steps to calm the pooch down. We’ll discuss that later.

Of course, a dog that barks at strangers is not always an entirely bad thing. After all, you’ll be grateful to have a four-legged security guard is somebody tries to break into your house in the middle of the night; a pooch that rolls over for a tummy tickle in such a situation and says, “sure, take the TV – you’ll be coming back to play afterwards, right?” isn’t much use.

However, you may find that your dog takes a dislike to a particular person, such as a friend or family member. This could be an issue if the individual in question is a regular visitor to your home!

Dogs Disliking Particular Individuals

We’ve made a few references as to how dogs and mailmen are mortal enemies, and that has been done with tongue firmly in cheek. However, there is no denying that some dogs do take a seemingly random dislike to specific individuals.

This can seem like loathing at first sight, and many dog owners take this seriously. After all, dogs are excellent judges of character right? If they do not take to somebody, they must sense something that we don’t.

The truth is, there are many reasons why dogs take a dislike to certain people. It could be as mundane as the fact that this a new person that has yet to gain Fido’s trust, and an insecure dog is concerned that they will steal the attention and affection of their owner.

Dog Aggressive Because It Dislikes Your Scent

Perhaps this infiltrator is a – whisper it quietly – cat person, and carries the distinct scent of the enemy all over their clothes. There could be a laundry list of other scents that deter a dog, too.

If the person in question works in catering, for example, they may have traces of vinegar or citrus fruit on their person – both of which are loathsome to our furry friends. There could even be the smell of an unfamiliar dog, which will either be intriguing or intimidating, depending on the canine in question.

Dog Dislikes the Sound of Your Voice

Sometimes, much like humans, dogs don’t like the cut of somebody’s jib, and it takes a while for them to warm up!

There are many more scientific reasons why some dogs dislike particular individuals, however. Perhaps the most important of these is their voice.

Dogs may understand particular words, but they respond more to the tone of voice used. This is understandable, as Fido probably hears his name hundreds of times over the course of the day as people make a fuss of him. When it is shouted in a short, sharp tone that is out of the ordinary – perhaps because he is about to wander out into traffic and needs to stop at once – fear kicks in.

Scientific studies have shown that dogs respond better to a higher-pitched, gentle tone of voice. This is linked to the reward center of the canine brain. After all, we all tend to use a soft voice when offering a treat and a cuddle and saying, “good boy!” or, “good girl!” when our pets do something to please us.

A dog will assume that somebody that speaks in a deep, booming voice is angry with them and is behaving aggressively. This will mean that a dog will respond in kind – either growling, snarling and barking, or running away with their tail between their legs. This means that, when introducing a potentially aggressive dog to a new person, they should always approach the pooch with a soft, welcoming tone.

Dog Doesn’t Like Your Body Language

It’s not just our voices that dogs listen to, though. They also pay a great deal of attention to our body language. That’s primarily how these tail-wagging critters communicate with each other (more on that shortly), so they’ll make sure they investigate how a strange human is presenting himself or herself.

Sudden movements – even if they are designed to offer a gentle pat or a stroke – make dogs skittish. This can launch a fear-based aggressive response. Fido is basically saying, “keep your hands where I can see them, please.”

Likewise, a dog may stare lovingly into the eyes of their owner for hours, but humans should never try to earn a canine’s affection by attempting this trick themselves. Dogs see direct, uninvited eye contact as a threat and an attempt at establishing dominance. This will launch an instant distrust and dislike.

dog aggressive towards one person

Past history will also need to be taken into consideration, especially if a dog has been rescued from a shelter. Many pooches end up in such an environment because they have been mistreated in the past, and that will live long in the memory.

Some dogs will only seek comfort from female humans and behave aggressively towards men if a male owner has abused them in the past, and vice versa. Scents could also trigger a reflex memory, so it could be worth changing a preferred perfume or cologne in the event of a dog taking an instant dislike to a human. It may simply be a case of negative connotations.

Finally, as we have previously established, our furry friends like to have our backs. According to the New Scientist, this means that anybody who behaves rudely towards a human owner will earn immediate distaste from a dog, as canines judge strange humans based on how they treat their loved ones.

If your dog hasn’t taken to your new partner or a particular family member, ask yourself how this person has treated you in the past. Also, remember that dogs can scent pheromones. If this individual has caused you to feel afraid, intimidated, upset or frightened in the past, their card will be permanently marked as unwelcome in your dog’s territory!

Why Dogs Bark at Other Dogs

We have covered why dogs display aggressive behaviors towards humans. What about hounds that are fine with people, but struggle to get along with other dogs? It’s a common problem for many owners, especially when taking their pet out for what should be a pleasant stroll.

Territorial Dominance in Dogs

One of the primary causes of this behavior is one that we have already covered: territorial dominance. A dog staring at their canine rival, making eye contact and stiffening their tail, usually accompanies this kind of barking.

In this instance, it isn’t necessarily dangerous. It’s merely a warning shot across the bows from one dog to another. They do this in the hope that the last resort of fighting for the territory will not be necessary.

This behavior stems from a love of routine. Once a pooch visits the same place many times, they start to think of it as ‘theirs’ because dogs do not understand the concept of public spaces.

If they visit the same park every day, that becomes their park. If they take a long walk in the woods every day, that whole forest belongs to them and their owner. Nobody else is welcome without their explicit invitation!

This is why our furry friends like to stop and sniff everything, then strategically pee. They are inspecting the area to see who has visited previously and laid claim to the territory. They will then request to join a pack (by urinating in the same spot), or claim something else as their own (peeing on the next fire hydrant over).

The point is, if a dog is displaying territorial dominance it isn’t too much to worry about – it’s mainly posturing. However, Fido should be removed from the area before the situation escalates. This could include snarling and growling. If this starts to happen, the animals will need to be separated immediately.

Dog Scared by a Bad Experience

Of course, as with humans, dogs also bark out of fear. Again, this is primarily a matter of bravado. Your furry friend may have endured a scary experience at the hands of a particular breed in the past, for example, and that means they instinctively bark at any similar-looking canine they encounter.

This is partly to scare off the other animal, and partly to act as a warning; a notice to humans that a dangerous presence is in the area, and perhaps more pertinently, a heads-up to other dogs that they should protect their weaker pack members and puppies.

Another thing that you may notice is that Fido only reacts negatively to particular dogs, despite cheerfully greeting or ignoring 99% of others. Some dogs, just like some humans, can’t get along. If this appears to be the case, it’s best that the human owners make an effort to stagger their walkies times and keep the beasts apart. Like a pair of aging western gunslingers, the town isn’t big enough for the both of them. You may even find that a dog doesn’t want to leave the house because it is scared.

If the same dog appears to continually growl, snap and snarl at other dogs, seemingly at random, it could point to a deeper-rooted behavioral problem though. A professional should investigate this as quickly as possible.

Dog Breeds Prone to Aggression

It’s important to note that every single dog is an individual. Upbringing and personal temperament are almost certainly more likely to result in aggressive behavior than genetics.

However, this doesn’t change the fact that some dog breeds are more prone to aggression than others.

According to Pet Helpful, these are the ten most aggressive dog breeds:

  1. Chihuahua
  2. Dachshund
  3. Chow Chow
  4. Doberman Pinscher
  5. Dalmatian
  6. Rottweiler
  7. Jack Russell Terrier
  8. German Shepherd
  9. American Staffordshire/ Pit Bull Terrier
  10. Siberian Husky

Surprised? Don’t be. As the list above goes to show, size isn’t everything when it comes to dog behavior and aggression. As unlikely as it may seem, a Shih Tzu can be every bit as dangerous and antagonistic as a German Shepherd if untrained and left to lash out as strangers.

If you have any concerns about aggressive actions from your dog, make an appointment with a behavioral specialist as quickly as possible. Just because a canine is small, it doesn’t mean that it cannot do some severe damage to a child or another pooch if their hostility is not managed.

Dog doesn't like people he doesn't know

How to Calm an Aggressive Dog

As previously intimated, a dog that is prone to constant and seemingly random bursts of aggression should be taken to a specialist. This could get out of hand before we know it, and lead to dangerous outcomes.

Here are some quick tips:

  • Keep your dog on a leash: If there is any danger of your dog becoming aggressive, ensure that they are kept on a tight leash. Avoid collars around the throat, as that can be dangerous for the canine in question. Look into a harness that fits across the body instead, as this means that you’ll be able to pull your dog away from another human or animal without hurting them.
  • Don’t be aggressive: Never attempt to restrain an angry or aggressive canine by wrapping your arms around them. This will make the dog panic, and only heighten their anxiety and aggression as they become determined to escape. Offer soothing words and gestures, such as strokes. Fido will calm himself down as quickly as he wound himself up.
  • Avoid extendable leashes: If you are concerned that your dog may become aggressive at any point, also avoid using an extendable leash. Keep the cord short, so you are always close by and in control of your pooch pal. This will also likely keep Fido calm, as it means that you are always nearby.
  • Use firm commands: Have a special command that is used sparingly, for when you need to capture your dog’s attention. They hear their names dozens of times every day – and despite their excellent hearing, dogs can have a propensity for selective deafness when the mood takes them! Use a short, sharp command like, “come away!” or, “leave it!”, or even a dog whistle. This should break the almost trance-like state that your dog finds himself or herself in when they become aggressive.
  • Muzzle your dog: If you absolutely must use a muzzle to prevent an aggressive dog from attacking other canines, never do so as a punishment. When applying the muzzle, pop one of your canine chum’s favorite treats inside so it can be seen as a positive thing.

Of course, prevention is always better than cure. Try to observe any doggy behaviors that spark aggression, especially if it’s out of character. This can be particularly important with rescue dogs, which may have been mistreated in the past. Find out whatever you can about your pet’s history before you bring them home.

Once you know what acts as a trigger for aggressive behavior, try to expose Fido to this in a safe environment – such as your home – and reward him with treats as soon as he doesn’t react to any negative stimulation.

Dogs are trainable by their very nature, and your dog will not be ‘broken.’ They need to learn to act differently. Remember, most dogs would be mortified at the idea of disappointing or upsetting their human parents, and they want a quiet life and to be happy!