Last Updated on April 22, 2023
No one wants to have to worry about an aggressive dog. Landlords prohibit them, home insurance can cost double if you own one, and lawsuits can drain your finances.
In this guide, we’ll discuss aggressive dogs, including which breeds to watch out for and how to avoid creating a vicious dog.
What is Dog Aggression?
When we say “aggression,” what are we talking about, exactly?
Basically, aggression is behavior in the wrong time and place. A dog that barks and growls at a coyote while guarding a flock of sheep isn’t considered aggressive. But a dog that barks and growls at a friendly human is.
Here are some of the things you should watch for: rigid posture, barking, lunging, growling, showing teeth, snarling, snapping, nipping, biting, or shoving their muzzle into a body part hard enough to feel like a punch.
Bites can range from quick little nips that leave no mark to clamping down and shaking, drawing blood, and even breaking bones.
Any dog breed can be aggressive, but some have been bred to be naturally more aggressive than others.
There is also the question of nature versus nurture. Some dogs might have aggressive tendencies, but others are made to be aggressive through life experience.
We can’t discount the role that irresponsible owners play. Some people want their dogs to be aggressive because they want a guard dog or to seem tough.
But a well-trained guard dog isn’t aggressive unless the situation warrants it.
A dog that acts aggressively when the situation isn’t right is considered aggressive and even dangerous.
Dogs can be aggressive to just other dogs, other mammals, adults, children, or all of the above. That’s why some people worry about certain dog breeds with children.
But again, no dog breed is always inappropriately aggressive. It’s all about socialization and training.
Is My Dog Dangerous or Is It Aggressive?
Do the two things refer to the same trait?
Aggression isn’t the same thing as being dangerous. Dog owners want a dog to be aggressive under the right circumstances.
A dangerous dog is one that you can’t predict and one that behaves aggressively when you don’t want them to.
A dangerous dog can’t be trusted, and they don’t make good pets without some serious training.
When we talk about dangerous dogs, what do we mean?
Groups like the Centers for Disease Control have done studies to determine which breeds are most likely to act aggressively, but these studies are largely flawed because of the sample size.
There is also the issue of whether a bite is reported or not. More people report a major attack from a large dog than a nip from a small dog simply because the damage is less severe.
That doesn’t mean the dog is less aggressive, however, just less capable of damage.
Still, we can determine which dogs are most dangerous by the number of medical issues, deaths, and serious injuries that a breed causes, as Forbes recently reported.
Common Reasons for Aggressive Behavior in Dogs
There is a vast difference between an aggressive incident and aggression. For instance, a dog might bite if you take it to the groomer and get scared while its nails are being trimmed. Otherwise, the dog might be docile and friendly.
Then there are dogs that constantly lunge and other dogs or that nip at their owners anytime they try to touch the food bowl. One is circumstantial, while the other is more of a personality.
Illness is a very common cause of aggression. Some dogs may be sweet and calm their entire lives until they get sick. Dogs naturally want to protect themselves when they are weak, and they may lash out.
Illness is related to fear, which is another common cause of aggression. If a dog is afraid, they may bite first. The same goes for pain.
Then there are the things that are more of a life-long behavioral issue. For instance, a possessive dog or protective of food, a toy, or a human might act out.
Then there are dogs that show aggression in social situations when they are outside of the home.
Some dogs lash out when they are frustrated or annoyed. Others simply want to show that they are dominant.
Then there are dogs who are anxious. Instead of waiting for something terrible to happen to them, they attack to ease their anxiety.
Some breeds are more prone to aggression than others. That’s because they were bred to be fighters or guardians. But just because a dog was bred to have these traits doesn’t mean that they will necessarily bite.
Sometimes biting can even be a good thing. For instance, some German Shepherds are trained to latch onto a person and hold them down until law enforcement can arrive. Watchdogs are expected to chase and/or bite intruders.
But a dog that bites when it shouldn’t is often surrendered to places like the Humane Society or the ASPCA simply because their owners don’t know what to do about the problem.
What Dog Breed is the Most Aggressive?
Some dogs were bred to be aggressive – but remember: that doesn’t mean that they should be aggressive all the time.
Dogs that were bred to be aggressive were bred to be so only during the appropriate circumstance. Whether that is guarding, herding, hunting, or fighting, there is a time and place for that natural behavior.
It’s never appropriate at the wrong time, and that’s the difference between a naturally aggressive dog and a dangerous one.
Small Aggressive Dog Breeds
Small dogs are often accused of having “small dog syndrome.” They like to act tough in order to compensate for their small size or because their humans haven’t corrected them appropriately because they are so small.
Terriers of several breeds typically have the worst reputation.
Let’s just say it. Chihuahua’s have a bad reputation. Anyone who watched Cesar Milan’s Dog Whisperer television show back in the day will remember that he often encountered naughty Chihuahuas.
Here’s Cesar Milan talking about training a tough dog that was a real challenge for him. This dog was a Chihuahua.
Read more about this pint-sized pooch in our handy Chihuahua guide.
Dachshunds are adorable with their little, stubby legs, but they are terriers at heart. That means they have a tough side bred to contend with some seriously aggressive foes like badgers and prairie dogs.
Sometimes, that terrier nature can go too far. Read more about this delightful dog in our article on Doxies.
3. Jack Russell Terrier
The Jack Russell Terrier is incredibly smart and has a lot of personality, but that doesn’t mean they are always on their best behavior. To find out more, read our Jack Russell guide on this happy little friend.
Medium-Sized Aggressive Dog Breeds
It’s not always the giant breeds that cause the most damage. Many medium-sized dogs are considered among the most dangerous.
4. Chow Chow
Chows were bred to be stubborn and independent. While that can be a good thing when they’re doing their job of protection, it’s a bad thing if it gets out of hand.
Read our Chow Chow guide to learn more about this fluffy bear.
Many insurance companies won’t cover Rottweilers or charge extra for them. That’s because Rotties were bred as guardians and are independent and tough.
They’re extremely popular in the US, and according to Zacks, they are more likely to attack, which puts them high on the list.
That doesn’t mean they aren’t wonderful pets. It just means that only experienced owners should bring one home.
While Dalmatians don’t top the list of aggressive breeds, they can be dangerous if not well socialized and carefully bred.
Dalmatians weren’t bred to be aggressive, but poor breeding (much of which resulted from their popularity after Disney’s 101 Dalmatians) caused problems in many lines.
On top of that, Dalmatians need a lot of exercise and mental stimulation. Otherwise, they can become aggressive or shy.
7. Shar Pei
Shar-Peis used to be used as fighting dogs. They also have a stubborn and independent personality.
That doesn’t necessarily mean that they will be aggressive, but the chances are higher than with some other breeds.
Read more in our guide on Shar-Peis.
8. Pit Bull
“Pit Bull” is a catch-all term that applies to dogs with a similar heritage and appearance. Learn more about the four different breeds that make up the “Pit Bull” category in our guide.
Collectively, Pit bulls are considered some of the most dangerous dog breeds.
When it comes to dog bite statistics, the Pit Bull types are the most commonly reported.
American Pit Bull Terrier: Originally bred to bait bulls and used as farm dogs, American Pit Bull Terriers make exceptional family dogs these days, but you do need to use some caution. These dogs require proper training and good socialization to be the best pet that they can be.
American Staffordshire Terrier: The bold and loyal AmStaff is a good friend for the right owner, but remember that these dogs were originally bred as fighters. They have a high prey drive and might not be ideal for first-time owners. For the right person, they make a wonderful companion.
Staffordshire Bull Terrier: The Staffordshire Bull Terriers came from England, where they were bred to be fighters. Today, most people know them as lovely family pets, but they still have that fighting instinct. Good training and socialization are a must.
Large Aggressive Dog Breeds
When a large breed attacks a human, it’s a huge deal. A chihuahua might leave little teeth marks, but a large breed can cause serious damage or even death.
While Pit Bulls cause the most bite-related fatalities, Rottweilers and German Shepherds come in second and third. Here are the most aggressive large breeds of dogs.
9. German Shepherd
GSD wolf hybrids are even more dangerous. That said, good training and socialization and teaching all family members how to lead their pack results in a happy, safe family pet.
10. Doberman Pinscher
Dobermans are fearless, loyal, and smart. These working dogs make excellent guards or protectors, but that strong personality can lead to trouble in the wrong hands. Read more in our guide on Doberman Pinschers.
11. Cane Corso
Cane Corsos are mastiff-type dogs from Italy, and while they are calm, stable, and even-tempered, they have been banned in many places because of their fearsome reputation.
Akitas are bold, independent dogs that have been known to be aggressive. There are generally two types: the Japanese and the American Akita.
There aren’t records, however, on whether or not one is more aggressive than the other.
13. Alaskan Malamute
While Alaska Malamutes haven’t been trained to fight other dogs, they are one of the breeds responsible for most dog bites. Learn more about this beautiful dog in our Malamute guide.
14. American Bulldog
The American Bulldog descended from the Old English Bulldog and has been used to fight in the past. Now, they make energetic, athletic pets, but they can be dominant and stubborn, so they need a strong leader.
15. Bull Mastiff / Bullmastiff
Bullmastiffs and Mastiffs were bred to be guardians to protect property and game. That means they won’t back down from a challenge, but they also make loyal and affectionate friends.
Learn more about this loyal pooch in our Bullmastiff guide.
16. Dogo Argentino
The Argentine Dogo is a large, strong breed that was created for hunting. They are protective of their people and extremely brave, but they are also often banned because they look like many other mastiff-type dogs.
17. Great Dane
The Great Dane is a big dog, but it also has a big heart. While there have been some bite instances, these dogs can make great pets with the proper training and socialization. Find out more in our guide to Great Dane.
18. Perro de Presa Canario (Canary Mastiff)
Another mastiff-type dog, this one hails from the Canary Islands. There haven’t been many bite instances by a Canary Mastiff in the US, but there aren’t many of them there, either.
19. Wolf-Dog Hybrid
Wolf hybrids are almost universally banned by landlords because they are less predictable and reliable than dogs. Because they are less domesticated and more difficult to train, these are not dogs for a first-time owner.
Other Aggressive Dog Breeds
- American Bully
- Australian Shepherd
- Bull Terrier
- Cocker Spaniel
- English Bulldog / Bulldog
- Fila Brasileiro
- Rhodesian Ridgeback
- Shiba Inu
- Tosa Inu
What is the Most Dangerous Dog?
According to the research from Forbes, Pit Bulls are the most aggressive dogs, followed by Rottweilers, German Shepherds, Mixed-breeds, American Bulldogs, Mastiffs, Bullmastiffs, Huskies, Labrador Retrievers, Boxers, and Doberman Pinschers.
While they don’t cause the most damage or medical claims, Chihuahuas are considered the most “dangerous” small breed.
What breed of dog has the most attacks?
AAHA reports that Pit Bulls bite most often and cause the most damage per bite. Of the small breeds, Chihuahuas tend to bite the most.
While Beagles aren’t considered one of the most dangerous breeds, a study shows that they are the most likely to bite their owner.
A vast majority of dog fatalities in which a dog kills a human involved a Pit Bull.
What is a Temperament Test for dogs?
Many breeders put puppies through a temperament test to determine their general personality. Some dogs are naturally more timid or quiet; other dogs are more naturally dominant.
A test at an early age can help people determine their personality and match the dog with the right person.
Adult dogs can also go through a personality test. This is especially common when adopting a dog. While there are numerous tests, the ATTS Temperament Test is the most often used to assess a dog breed’s temperament.
How is the test conducted?
In a temperament test, a dog is approached and interacts with a neutral stranger and a friendly stranger. Then they are subjected to noises that range from fairly quiet to very loud.
Then someone opens an umbrella near them, and the dog is asked to walk on unusual footing. Also, during the test, the dog is asked to interact with other dogs in various situations.
The dog is rated on a scale, which helps determine how fearful, aggressive, or friendly the dog is. Of course, no test can completely answer the question of personality, mainly because the tests are given in an unusual environment.
Frequently Asked Questions (FAQs):
What are breed restrictions?
Companies and individuals create breed restrictions to limit their risk from canine aggression. Some limit dogs by breed, while others limit dogs by weight or age.
Little dogs are usually OK, while larger breeds are more often restricted.
While this may seem like discrimination, any private company or landlord can choose who they rent to, and that includes dogs. While it might not be fair, it’s the law.
Additionally, some cities have introduced Breed Specific Legislation, which might mandate that certain dogs are banned.
Some cities require certain breeds to be spayed or neutered.
For the most part, the intentions of these individuals, companies, and cities are good. They are trying to protect small children and the vulnerable from being attacked by dogs.
They also want to avoid dogfighting and limit their liability.
What are aggressive dog breeds banned by apartments?
Many apartments ban breeds that they have determined are dangerous or unsuitable.
This usually includes Pit Bulls, Dobermans, Rottweilers, German Shepherds, Great Danes, Alaskan Malamutes, Siberian Husky dogs, and some terriers.
What dog breeds do insurance companies consider aggressive?
Some insurance companies also refuse to cover certain breeds or have a much higher insurance rate. In addition to the dogs listed above, insurance companies may ban wolf hybrids, Akitas, and Presa Canarios.
What can I do if my dog is banned?
If you have a banned breed, it can be hard to find a place to rent. However, don’t just assume that you’re stuck. You can always argue your case with the landlord.
If you intend to try to get an exception, be prepared. The first step is to request an interview to have your individual dog examined by the landlord.
Bring along a “dog resume” which may include training they’ve had or any awards they’ve received.
Be sure to provide references and include your vet records. You might also want to create a video showing your dog interacting positively with people and other pets.
You might want to offer to pay a larger deposit and monthly pet rent, as well as getting insurance to cover any situation.
What is the friendliest type of dog?
Want to avoid even the danger of being bitten? While no breed is 100 percent guaranteed not to bite, dogs that were bred to carry things often have “soft mouths.”
Think Bernese Mountain Dogs, Golden Retrievers, and Newfoundlands.
To learn about some of the friendliest dog breeds out there, you might want to read our helpful guide.
The Takeaway: No Breed is Inherently Vicious
Remember that no breed is inherently aggressive. Owning a Pit Bull doesn’t guarantee that your dog will be vicious. Some of the sweetest dogs out there are Pit Bulls.
The same thing goes with owning a Golden Retriever. While most of them are gentle, some out there can be mean.
The most important element is good training and extensive, consistent socialization. That’s how you ensure that you will have a friendly, stable, reliable dog that isn’t prone to snapping, biting, or other bad behavior.
Do you own any of the dogs mentioned in this article? Let us know all about them in the comments below.
Further reading: Find the Perfect Breed For You
- Best Small Dogs for Kids
- Best Large Dogs for Families
- Best Dog Breeds for Seniors
- Best Low Maintenance Dog Breeds
Cess is the Head of Content Writing at K9 Web and a passionate dog care expert with over 5 years of experience in the Pet Industry. With a background in animal science, dog training, and behavior consulting, her hands-on experience and extensive knowledge make her a trusted source for dog owners.
When not writing or leading the K9 Web content team, Cess can be found volunteering at local shelters and participating in dog-related events.