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Top 10 Most Aggressive Dog Breeds

Aggressive dogs bite people more than 4.5 million times each year, according to the American Veterinary Medical Assocation. About 20 percent of those dog bites need medical attention.

If you're thinking about adopting a dog, it's natural to worry about whether they will become aggressive and bite you or someone you love. Find out what makes dogs aggressive, what the most aggressive breeds are and how you should factor breed aggression into your decision to get a dog.

What Makes a Dog Aggressive?

A 2021 University of Helsinki study collected data from 13,715 dogs, including 1,791 dogs with frequent episodes of aggressive behavior. The researchers identified several factors contributing to aggressiveness:

Fearfulness. Fear was the most significant contributor to aggressive behavior. Much more than breed or other factors.

Age. Older dogs were more likely to be aggressive. Possibly because pain from chronic illness makes them less patient with humans.

Gender. Male dogs were more aggressive than females. Sterilization did not affect aggressiveness.

Size. Small dogs were more aggressive than larger breeds. Possibly because they are more fearful towards humans and animals much larger than them.

Owner experience. Pets of first-time dog owners were more likely to be aggressive.

Socialization. Dogs who didn't have canine companions were more likely to be aggressive towards people.

Breed. Dog breeding is another factor that influences aggression, but its influence is not overwhelming. Training can help dogs from more aggressive breeds get along with humans and other animals.

10 Most Aggressive Dog Breeds

The University of Helsinki published data on aggressiveness in 22 dog breeds. These 10 dogs are more aggressive than average:

1. Rough Collie Rough collies are famous for their soft coats and loyal temperments. IStock/Getty Images Plus

Average Weight: 40 to 65 lbs

Average Height: 20 to 24 inches

Life Expectancy: 14 to 16 years

The loyal and loveable Lassie popularized this breed. But like the TV star's antics, its reputation as a friendly dog might be fiction. Rough collies (or long-haired collies) were the most aggressive breed in the University of Helsinki's study.

These dogs are known to be very energetic and alert. That might contribute to their aggressiveness towards strangers. They are also very loyal and may snap when their family is threatened.

2. Miniature Poodle Miniature poodles are small, but surprisingly aggressive. IStock/Getty Images Plus

Average Weight: 10 to 15 lbs

Average Height: 10 to 15 inches

Life Expectancy: 13 to 15 years

Like other small dogs in the University of Helsinki's research, miniature poodles behave aggressively to make up for their size. They are very energetic, and their hyperactivity can sometimes escalate to more aggressive behavior. Miniature poodles often come across as "yappy," rather than dangerous, but they are still one of the most aggressive dog breeds according to the study.

3. Miniature Schnauzer Miniature schnauzers are smaller versions of their full-sized cousins. IStock/Getty Images Plus

Average Weight: 12 to 20 lbs

Average Height: 12 to 14 inches

Life Expectancy: 12 to 15 years

A smaller version of the standard schnauzer. Miniature schnauzers were bred in Germany in the 19th century as guard dogs. Their stature may make them more aggressive than their larger cousins.

Miniature schnauzers are also fearless, despite their size. They won't back down in the face of a fight, which can cause normal situations to escalate.

4. German Shepherd German Shepherds are famous for their work as police and military dogs. IStock/Getty Images Plus

Average Weight: 49 to 88 lbs

Average Height: 22 to 26 inches

Life Expectancy: 9 to 13 years

German shepherds frequently serve as police or military dogs, but not because of their aggressiveness. Instead, it's because they respond well to training. German shepherd owners can use this to their advantage and train their dogs to behave well.

These jobs help them burn off all their energy. Without enough stimulation, they can turn their liveliness towards aggression.

5. Spanish Water Dog Spanish water dogs have identifiable wooly coats. They were originally bred as hunting dogs in Spain. IStock/Getty Images Plus

Average Weight: 31 to 49 lbs

Average Height: 15 to 20 inches

Life Expectancy: 10 to 14 years

These medium-sized dogs, known for their woolly curls, were originally bred to retrieve downed waterfowl. That may contribute to their above-average aggressiveness. Today, they're prized as athletic family dogs that can act as vigilant watchdogs.

6. Lagotto Romagnolo Lagotto Romagnolo dogs are curly-haired truffle-finding dogs from Italy. IStock/Getty Images Plus

Average Weight: 24 to 53 lbs

Average Height: 17 to 18 inches

Life Expectancy: 15 to 17 years

The curly-coated Lagotto Romagnolo breed began as a truffle-hunting dog in northeastern Italy. Like other working dogs, they can be very energetic and need plenty of stimulation, so they don't turn aggressive. Fortunately, they also respond well to training, so owners can help reign in any aggressive tendencies.

7. Chinese Crested Dog Chinese crested dogs have haired and hairless varieties. IStock/Getty Images Plus

Average Weight: 7 to 12 lbs

Average Height: 9 to 13 inches

Life Expectancy: 13 to 15 years

Chinese crested dogs are one of the smallest dog breeds in the world. The breed is most known for its hairless variety, which has only tufts of hair around its paws and head.

Their size contributes to their aggression, along with their energetic temperament. These dogs are also highly intelligent. Owners can take advantage of that trait and teach them tricks. This burns off energy and manages their aggressive dispositions.

8. German Spitz Mittel German spitz mittel dogs are small, but fearsome dogs with floofy coats and powerful yaps. IStock/Getty Images Plus

Average Weight: 15 to 24 lbs

Average Height: 12 to 15 inches

Life Expectancy: 13 to 15 years

These small dogs have poofy coats and a reputation for yapping. They're devoted to their owners, but very distrustful of strangers. They can make great watchdogs, and they'll always sound the alarm when they see an intruder.

9. Coton de Tuléar Coton de Tuléar dogs are famous for their white, cotton-like coats. IStock/Getty Images Plus

Average Weight: 8 to 13 lbs

Average Height: 9 to 12 inches

Life Expectancy: 14 to 16 years

Cotons are famous for their fluffy white coats and vocal personalities. They form very close bonds with their owners, and they make excellent companions. But as small dogs with lively temperaments, they're prone to aggressive behavior.

10. Wheaten Terrier Wheaten terriers are famous for their beards. IStock/Getty Images Plus

Average Weight: 30 to 40 lbs

Average Height: 17 to 19 inches

Life Expectancy: 12 to 15 years

These bearded dogs come from Ireland, where they were bred to hunt and kill vermin. Their soft coats might give you the impression that these dogs have a soft temperament, but they were originally bred as working dogs. They carry over the energy and aggression from those early days, but with training, they can be loving family dogs.

What Are the Least Aggressive Dogs?

Golden retrievers and labrador retrievers were vindicated by the University of Helsinki study. They were the least aggressive dogs among the breeds studied.

Shetland sheepdogs and Lapponian herders were all near the bottom of the list, making them more peaceful than many other dogs.

The Staffordshire bull terrier rounded out the list as the fifth least aggressive dog. This dog commonly appears on "most dangerous breed" lists as a member of the pit bull category, but data from the University of Helsinki doesn't support that idea.

The University of Helsinki's research should cause us to reexamine many of our beliefs about the most aggressive dog breeds. Small dogs and miniature breeds appear frequently in the top 10, while the usual suspects like pit bulls or rottweilers are proven to be less aggressive based on the probability of aggressive behavior.

Of course, a pit bull's bite would prove deadlier than a chihuahua's—so it's crucial to train larger dogs, even if their breed is technically less aggressive.

Should You Avoid Aggressive Dog Breeds?

No. If you find a dog you like, don't stop yourself from adopting it just because of its breed.

Breed is just one of many factors that can contribute to aggressiveness. Its contributions are minor compared to training, environment and how you behave around the dog.

Breeds can also be hard to determine. Animal shelter workers frequently misidentify dogs as pit bulls, a breed thought to be more aggressive than others.

The bottom line: dogs don't bite because of their breed. And concerns about breed aggressiveness should not stop you from adopting a particular dog.

FAQs About Aggressive Dog Breeds

If we don't have an answer to your question about aggressive dogs, ask your vet or a professional dog trainer.

Can You Train a Dog to Be Less Aggressive?

Yes. Training is a major factor in managing aggressiveness. And it could be one of the reasons why first-time dog owners tend to raise more aggressive pets.

To manage your dog's aggression, try working on:

Socialization. Take your dog to the park where they can practice socializing with dogs and humans.

Recall. If your dog responds quickly when you recall them, you can pull them out of dicey situations before things turn aggressive.

The cause. Dogs usually aren't aggressive for no reason. They respond to situations or stimuli. If you can find out what sets your dog off and address it, you can reduce their aggression.

However, training an overly aggressive dog takes skill and patience. If you haven't trained dogs before, call a professional trainer to help manage your pet's aggressive behavior.

Is Dog Reactivity Different from Aggressive Behavior?

Yes. Dog reactivity and aggressive behavior are not the same.

Reactive dogs overreact to common stimuli. They lunge, bark and growl in situations where other dogs would behave normally, like seeing other dogs at the park or meeting strangers. This might be because they're fearful of an uncertain situation or hyperstimulated.

Reactive dogs are not aggressive dogs. However, they can be pushed into aggression. If your dog is reactive, make sure to give them space and speak with a trainer about managing their reactive behavior.

Dr. Katherine Houpt, the James Law Professor Emeritus of Behavior Medicine at Cornell University, recommends advocating for your dog's personal space. In the short term, keep them away from stimuli that trigger reactivity. This will show them they can feel safe and calm outdoors.

In the long term, train them to behave well around the troubling stimuli. Houpt recommends keeping treats on hand and rewarding your dog as soon as their trigger appears. This will help them associate the trigger with something positive.

Do Apartments Allow Aggressive Dog Breeds?

It depends on the apartment. Apartments commonly ban these dog breeds, commonly thought to be aggressive:

Chow chows

Huskies

Rottweilers

German shepherds

Pit bulls

However, some of the most aggressive dog breeds, like rough collies, are rarely on apartment breed restriction lists. Apartment breed restrictions may have more to do with size and perceived danger than actual aggressiveness.

If you have a well-behaved dog that's part of a banned breed, talk to the apartment manager. You may be able to get an exception.

Emotional support animals are also exempt from breed restrictions, thanks to the Fair Housing Act. But you will need an emotional support animal (ESA) letter from a licensed mental health professional.

Does Insurance Cover Aggressive Dog Breeds?

Home insurance companies often have dog breed ban lists. Journalists working for Forbes analyzed ban lists at major home insurance providers and found that these dog breeds frequently appeared on them:

Doberman Pinschers

Pit Bulls

Rottweilers

Chow Chows

Wolf dogs and wolf hybrids

Insurance providers won't offer you a policy if you have a dog on their ban list. However, policies and ban lists vary between providers. Make sure to check with your insurance provider.

Breed is one of many factors influencing aggressiveness in dogs. However, that shouldn't stop you from adopting a dog that's more aggressive than average. Training can make any dog a good citizen, regardless of breed.

Uncommon Knowledge

Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.

Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.

Dog Bites 29 People, Beaten To Death

Chennai: A stray dog spread panic in the Royapuram area on Tuesday evening, biting 29 people in less than an hour on busy GA Road before it was beaten to death by locals who suspect it may have been rabid.Witnesses said the dog was lying on the road in the largely commercial area in north Chennai, when it suddenly attacked pedestrians, biting their ankles and feet. Some of the victims said the dog did not let go even when they tried to shake it off.The Greater Chennai Corporation has sent the dead dog to the Madras Veterinary College for postmortem. "The dog could be rabies infected as it has shown unprovoked aggression. We will get the test report in two days," said GCC veterinary officer Dr Kamal Hussain.Of those attacked, 24 had category three bites, which means deep cuts and bleeding with possible saliva transfer from dog to human. Ten of the injured were school children. Some senior citizens fell and hurt their heads too. All the injured were admitted overnight to the nearby Government Stanley Medical College and Hospital.Dr S Chandrasekhar, head of department, medicine, Stanley GH, said "We washed the lower limbs of all victims and gave them anti-rabies immunoglobulin medication to prevent infection from spreading to the brain. Following this, we gave an anti-rabies vaccine for which they have to come again for four more doses."Following the incident, the Greater Chennai Corporation rounded up 32 dogs from the area, including six puppies, and has kept them under observation for rabies. M Balagangatharathilagar, veterinary medicine specialist and TANUVAS professor, said victims of unprovoked dog bites should get anti-rabies immunoglobulin serum and vaccine doses within 12 hours."Street dogs are usually in packs and only chase vehicles in groups, if they find smell of other dogs' on the wheels or have previous memories of harm. If they are alone and attack somebody unprovoked the possibility of them being rabies positive is higher," he said.The professor said rabies tests can only be done on dead dogs through hippocampus fluorescent antibody tests where a part of the brain is removed to check for the virus. "In living dogs, a cornea smear test or saliva test can be done, but this is not always decisive as viral load may be less here," he added.We also published the following articles recentlyDog bite cases on rise, but many skip anti-rabies shotsThe district administration in Trichy has issued an alert regarding the increasing incidents of dog bites in the area. So far this year, there have been 21,243 cases of dog bites, with stray dogs accounting for 75% of the incidents. While not all dog bites cause rabies infection, those bitten are advised to take anti-rabies vaccines. The number of affected people seeking medical treatment for dog bites is increasing, but many still underestimate the importance of taking the vaccine. The animal husbandry department is also organizing awareness camps and special veterinary health camps to promote vaccination for pet dogs. Dog bites 29 people in less than an hour on busy Chennai road, beaten to deathA stray dog in Chennai bit 29 people in less than an hour before being beaten to death by locals. Witnesses said the dog attacked pedestrians, biting their ankles and feet. The Greater Chennai Corporation suspects that the dog may have been rabid and has sent its body for testing. Of the 29 people who were bitten, 24 had deep cuts and bleeding, with possible saliva transfer from the dog. The injured victims were admitted to the hospital and given anti-rabies medication. The corporation has also rounded up other dogs in the area for observation. Israel targets Hamas tunnels with attack dogs, sponge bombsIsrael's military is using a range of technologies to detect and destroy Hamas' vast network of tunnels in the ongoing conflict in Gaza. Surveillance drones, warplanes with bunker-buster bombs, bulldozers, attack dogs, unmanned vehicles, and robots are all being utilized to explore and destroy the underground complexes. The military is prioritizing blocking and damaging the network, but without ground forces, it is difficult to verify the extent of the damage inflicted. There is a concern that if the tunnels are not completely destroyed, they could be used for a long-term insurgency after the war ends.

Finding The Strongest Dog Bite In 10 Breeds

Although dogs are some of our closest companions, they pack a pretty powerful bite force. The average dog has an impressive bite force of 235 pounds per square inch (PSI). But which breed will deliver the strongest dog bite of them all?

What Determines a Dog's Bite Force?

Like all other animals that bite, a dog's bite force is determined primarily by its size. So a large dog like a Labrador Retriever will have a greater bite strength than a little Chihuahua, no matter how angry the Chihuahua is.

A 2020 study published in the Journal of Experimental Biology examined the relationship between bite force and jaw shape in domestic dogs and found that, while size is still the biggest predictor of bite force, morphology plays a role, too.

Large brachycephalic dogs — those with shortened snouts, like the Rottweilers, pit bulls and bulldogs — tend to have a biting advantage over the longer-snouted and smaller breeds. The study's authors believe the advantage could come down to the tasks the dogs were bred for:

"Most of the large brachycephalic dogs are historically dedicated to the protection of humans (such as the rottweiler), whereas small brachycephalic dogs are dedicated to companionship, and mesocephalic or dolichocephalic dogs are dedicated to herding or hunting. For skills such as protection or attacking, breeders try to improve biting or gripping ability. Thus, it is not surprising to observe relatively higher bite forces in large brachycephalic dogs that were bred for defence/attack rather than dogs bred for herding or hunting."

The authors also point out that bite force varies significantly among individuals of the same dog breed. Of the 10 Beagle specimens studied, bite force ranged from 559 to 1018 Newtons on the same tooth.

Central Asian Shepherd Dog. Sherret / Shutterstock

10. Central Asian Shepherd Dog: 500 PSI

The Central Asian Shepherd Dog is one of the world's oldest dogs, with a history that spans 5,000 years. Unlike other dogs on this list, which were bred specifically for tasks like herding, hunting and fighting, this particular breed developed through natural selection.

That doesn't mean they don't make great guard dogs. These protective dogs travel alongside nomadic tribes, protecting the people and livestock they live with. The breed stands 27.5 inches (69.9 cm) high at the shoulder and weighs 110 pounds (49.9 kg).

Perro de Presa Canario. TamaraLSanchez / Shutterstock

9. Perro de Presa Canario: 540 PSI

The Perro de Presa Canario ("Canary dog of prey") is a mollosser, a group of short-snouted dogs including the English Mastiff, Bullmastiff, Cane Corso, Dogue de Bordeaux, Tibetan Mastiff and Tosa Inu.

Bred as guard dogs to protect livestock and property, mollossers' large size and short snouts give them the strongest bite force of any group of dogs. The Perro de Presa Canario was used in dog fights until the practice was made illegal in the Canary Islands in the 1940s.

Tibetan Mastiff. Tatyana Kuznetsova / Shutterstock

8. Tibetan Mastiff: 550 PSI

With its huge size (males are at least 26 inches [66 cm] to the shoulder and weigh up to 150 pounds [68 kg]) and fluffy mane, the Tibetan Mastiff looks more like a lion than a dog.

The Tibetan Mastiff's history is murky. According to the American Tibetan Mastiff Association, it may have descended from an ancient Chinese dog, and its isolation in the Himalayan mountains may have contributed to its unique features. The Tibetan mastiff traveled with Tibetan sheepherders to protect sheep (and humans) from wolves and snow leopards.

Caucasian Shepherd Dog. Tatianasoba / Shutterstock

7. Caucasian Shepherd Dog: 550 PSI

Measuring up to 30 inches (76.2 cm) from paw to shoulder and weighing up to 170 pounds (77.1 kg), this large Eastern European shepherd dog has guarded livestock and humans from predators like coyotes and wolves for centuries. The American Kennel Club recognizes two breed standards: the heavier, long-haired Mountain type and the shorter-coated Steppe type.

English Mastiff. Monica Arauz / Shutterstock

6. English Mastiff: 552 PSI

The largest of the mastiff breeds, the English Mastiff measures at least 30 inches (76.2 cm) at the shoulder and weighs up to 230 pounds (104 kg).

According to the American Kennel Club, the English Mastiff dates back to at least 55 B.C.E., when the dogs apparently impressed Julius Caesar in his invasion of Britain. In Medieval England, English mastiffs were used as war dogs, big game hunters and guard dogs.

Today, the English mastiff is known as a "gentle giant." Despite their size (and strong bite force), many people believe English mastiffs make great family pets with proper training.

5. Black Russian Terrier: 556 PSI

Not technically a terrier, the Black Russian's impressive bite force is due to its large size: up to 30 inches (76.2 cm) at the shoulder and 130 pounds (60 kg).

Black Russian Terrier. Daryl Solomon / Getty Images

The black Russian terrier's origin story reads like a superhero comic.

According to the American Kennel Club, the Russian government commissioned breeders at its Red Star kennel to create a war dog more cold-hardy than the German shepherd.

After World War II, the kennel was able to import the Rottweiler and Giant Schnauzer from East Germany.

Those two dogs, plus the Airedale Terrier (also not a true terrier) and the Newfoundland, form the foundation of the breed.

Tosa Inu. Anita Kot / Getty Images

4. Tosa: 556 PSI

Also known as the Tosa Inu and the Japanese Fighting Dog, this large (21.5 to 23.5 inches [54.6 cm] tall and up to 200 pounds [90.7 kg]) short-haired dog was originally bred as fighting dogs. The Tosa is a hybrid of the Japanese Shikoku and Western breeds including Bulldogs, Mastiffs, German Pointers and Great Danes.

Dogue de Bordeaux. Little Brown Rabbit Photography / Getty Images

3. Dogue de Bordeaux: 556 PSI

The Dogue de Bordeaux ("dog of Bordeaux"), also known as the French Mastiff, isn't just large breed (up to 27 inches [68.6 cm] tall and 110 pounds [49.9 kg]). It also has the largest head (proportionally) of any canine, according to the American Kennel Club.

A large head means a big mouth, and a big mouth means stronger bite force. Originally bred for fighting, a Dogue de Bordeaux also makes an excellent guard dog or livestock drover.

The breed gained international recognition with the release of the film "Turner & Hooch" (1989), featuring a detective (Tom Hanks) who adopts a Dogue de Bordeaux after the dog owner's murder.

Cane Corso. Predrag Vuckovic / Getty Images

2. Cane Corso: 700 PSI

This ancient Roman dog's name translates roughly to "bodyguard dog." At 28 inches (71.1 cm) tall and over 100 pounds (45.4 kg), this molloser makes for an impressive bodyguard. Like the other breeds on this list, the Cane Corso is a working dog typically traditionally used for guarding farms.

Its thick, coarse coat is completely waterproof.

Anatolian Shepherd Dog. Ozgur Donmaz / Getty Images

1. Anatolian Shepherd Dog: 743 PSI

This ancient Turkish breed was developed to protect sheep during hot summers and freezing winters. Today, Anatolian Shepherds continue to work on farms and ranches.

The breed became popular in the United States in the 1970s with the passage of the Endangered Species Act, which required ranchers protect their livestock without killing endangered wolves.

Anatolian Shepherds, which can reach 29 inches (73.7 cm) and weigh up to 150 pounds (68 kg), were the perfect solution for intimidating wolves without killing them. Their large size explains why they have the highest bite force of any breed of dog.

Original article: Finding the Strongest Dog Bite in 10 Breeds

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