Breeds like pit bulls and rottweilers get a lot of attention as being “aggressive” breeds. In contrast, most people think of small and toy breeds as cute, clownish and harmless, but that is not always true.
Some small breeds have been bred to hunt and kill prey, and others can be aggressive due to fear or inbreeding, and you should take that possibility into account when choosing the right dog for you.
Here is a look at some of the most aggressive small dog breeds.
1. Manchester Terrier
However, like most terriers, the Manchester was bred to hunt vermin, and it was very good at that job thanks to its tenacious and sometimes even aggressive nature.
This terrier has a strong prey drive, which can lead him to be aggressive with smaller animals. He is likely to take off and chase birds, squirrels and other outdoor critters, so keep him leashed outdoors.
The Manchester terrier is not a good choice in a home with small pets like kittens, hamsters and guinea pigs. These pets will not be safe around a dog that was bred to hunt them out and kill them.
The Manchester Terrier is generally not a threat to humans if it is well trained. However, these dogs do need their own space, and can snap at people who refuse to leave them alone when they want some alone time.
As a result, they are not generally recommended for families with very young children. Older kids who can understand when the dog wants to be left alone should not have a problem, however.
2. Lhasa Apso
These dogs are intelligent and do well with obedience training. They can be taught to sit, heel and even beg if owners are persistent with training them.
However, there are a few character traits that new owners of Lhasa Apso dogs need to keep in mind.
Though often similar in appearance to Shih Tzus, the temperaments of Lhasa Apso dogs can be very different. The Shih Tzu was bred as a companion dog and tends to be friendly with people, even children.
In contrast, the Lhasa was bred to guard the temples in Tibet, and it takes that job very seriously. Lhasas tend to be standoffish with unfamiliar people, especially children, and can be nippy if approached too suddenly or boisterously.
This behavior is understandable given the small size of the dog, which can feel as though it needs to protect itself from larger humans.
Treat this dog with care and respect. Despite its small size, it is capable of inflicting a painful bite. However, in a calm environment with familiar people, the Lhasa Apso can make a very loyal pet.
3. Jack Russell Terrier
The Jack Russell was bred as a working farm dog, and it always wants to be in motion.
Owners of Jack Russell dogs need to make sure that their pets get plenty of exercise every day.
Otherwise, the dogs can become restless and irritable, and they might start to chew up the house.
The stubborn streak of a Jack Russell dog can make him tough to train, and his high prey drive can lead him to take on other larger dogs.
The Jack Russell can be hurt in these scuffles, so keep him leashed when in a park or other public place where other dogs can be present.
Unless taken in hand early on, the Jack will assume he is the alpha in any group and will act like it. This can lead him to act aggressively toward strange dogs and people, and many Jacks have little patience for children.
In order to make a Jack Russell a well-behaved member of your family, you need to start his training as early as possible. The dog must be taught to respect all humans, even the smallest child.
4. Cocker Spaniel
They are intelligent, energetic dogs that love to play and run around.
Take your Cocker spaniel to the park, and you will see him snuffling around with his nose in the grass, tracking scents, while his tail wags happily.
Cocker spaniels are also very popular companion animals, and have spent decades as one of the most popular dog breeds in the United States. This has led to some overbreeding issues, including a problem called “rage syndrome”.
A Cocker prone to “rage syndrome” can become suddenly aggressive toward strangers, people she knows, or even her own family, and just as suddenly become calm again.
Even without this disorder, a Cocker who is not well socialized as a puppy can tend to become high-strung and overly protective of its owner and territory. You can reduce your risk of getting a raging Cocker by purchasing your pup from a good breeder who understands the importance of socializing puppies from an early age.
A puppy that comes from good breeding stock can become a loving and cheerful member of your family, integrating well with all members of the household, including children.
5. Bull Terrier
This breed of dog is strong and energetic, which means they need vigorous exercise every day.
However, their short coats mean that they are very easy to groom.
The bull terrier has a similar origin to “pit bull” breeds – it was originally bred for pit sports, such as entering a ring full of rats and killing them quickly.
This instinct has not completely left the breed, and it is generally not recommended to keep a bull terrier around small pets such as hamsters, guinea pigs or rabbits.
The modern descendant is not as aggressive as its ancestor, but if not well trained can become domineering and hostile to strangers and other animals. Even bull terriers who display no behavior problems with their own family can be hostile toward strangers.
Like pit bulls, bull terriers are very muscular and tenacious, so if they do bite, it can cause serious injury. Owners need to be willing to put time and effort into training their dog to reduce the risk of biting or other types of aggressive behavior being displayed.
For example, they are a very popular breed for use in airport security, as they can sniff out drugs, weapons and even contraband agricultural products.
Once a scent catches a Beagle’s attention, she is single-minded in pursuing it and will often ignore commands from her master.
This trait can be frustrating when trying to get a Beagle back on the lead while out for a walk. Owners need to be prepared to be patient and firm to make the dog obey.
The typical Beagle has a very high prey drive and will chase down smaller animals, and sometimes take on dogs and other animals much larger than her. Beagles have to be well socialized early in life, or their headstrong ways will lead them toward aggression to strange animals and people.
Beagles can thrive around children, but you need to ensure that they understand their place in the household hierarchy.
Even the smallest child should be able to display leadership over the dog. To achieve a happy household, all members of the family need to take part in training the dog and getting to know how to handle it.
This royal pedigree shows in the Pekingese temperament even today.
He is a loyal and even playful companion, but tends to be aloof toward unfamiliar people and dogs.
A Pekingese can be fearlessly aggressive even to dogs who far outweigh him, which can be dangerous to his safety.
A Pekingese dog demands to be well-treated and can be nippy with people, especially children, who do not approach with proper respect. He has a tendency to be possessive of his people, his food and his space.
Pekingese dogs can thrive very happily in quiet, stable homes with a few familiar people. As long as the owner respects the dog’s need for its own space, a very happy companionship can develop. Pekingese dogs can be extremely affectionate with people that they know well.
These dogs need frequent grooming, including daily brushing of the long coat. However, their exercise needs are not excessive. A leisurely walk every day will burn off excess energy and keep the Pekingese in a calmer, less aggressive mood.
Like miniature poodles, papillons have often been used as performing dogs because they can learn to do complicated tricks.
This dog is perfect for an owner who enjoys putting a lot of time into training their dog and teaching it to do a range of tricks.
Today, papillons are one of the most popular breeds for agility training.
Papillons are often very aware of their small size and vulnerability to injury, and as a result they can be extremely sensitive to what they perceive as rough handling. Their reaction can be a defensive bite, which makes them a poor choice as a pet for small children.
It is very important to socialize papillons early in life, as their cautious nature can otherwise lead them to be easily frightened and overwhelmed by noises and crowds. Nervous papillons also have a tendency to become fixated on and overprotective of their owners.
Always buy papillon pups from a breeder who makes an effort to socialize puppies from a very early age. This early socialization reduces the risk of the behavior problems that these dogs can be prone to developing, such as aggressiveness or defensiveness.
However, they were bred to this form for a purpose: to track and kill vermin or prey, including following critters into thickets or tunnels.
Dachschunds had to be aggressive so that they could fight against the creatures, including fearsome badgers, that they were trained to track down and kill.
Even today, dachshunds are known for a high prey drive, which can be triggered by smaller and sometimes even larger animals. Dachshunds also tend to be one-person dogs, and protective of their person, which make them excellent companions for single or elderly people and good watchdogs.
However, this highly person-specific loyalty can also make them very suspicious of strangers and quick to nip or bite anyone it perceives as a threat. They are generally regarded as being a breed of dog that is not very good with children.
Even though Dachschunds often appear to have difficulty walking and running on their short, stubby legs, it is important to make sure that they get plenty of exercise.
They are very prone to putting on too much weight if not allowed to get outside and run around every day. Also, lack of exercise can increase the risk of aggression in these dogs.
Perhaps for this reason, they have become very fashionable, particularly among city dwellers who only have enough space for a small pet.
However, the small size of these dogs makes it easy to overlook the fact that they can also be one of the most aggressive breeds.
The tendency of many owners to coddle their chihuahua can also exacerbate bad behavior. Chihuahuas are very aware of the small size and fragility, and can tend to protect themselves by barking at or going on the offense against dogs or people many times their size.
Owners who do not keep this behavior in check can end up being bossed around by their miniscule pet, which will come to see itself as the alpha dog in the household. Chihuahua owners must be firm with their dog to assert their leadership.
Chihuahuas can also be extremely possessive of the owner that they see as “their” person, and become hostile to strangers or even other family members. These problems can be avoided by socializing the dog early in life.
11. Shi Tzu
The curly, flowing hair is prone to mats and must be brushed and shampooed constantly. The breed also has stubby little legs and a short, squashed muzzle and a severe Napoleon complex.
The tiny dog is a known biter, and that adorable under-bite can make a very painful pinch. The name “Shi Tzu” means “lion dog”, since the breed is said to resemble Chinese depictions of lions, though the name’s more for appearance than temperament.
Shi Tzu’s can range from pleasant, eager companions to vicious fighters. They are enthusiastically affectionate if socialized early, but the dogs do not respond well to threats. Loud children, strangers, and competing pets have all known the sting of a Shi Tzu’s teeth.
Fortunately they’re a hypoallergenic breed and they tend to get plenty of exercise going about their own business, so they’re a hit amongst urbanites and suburban moms dreading allergy season.
Shi Tzu’s remain popular across the United States and in the UK, though it must be said the little guys require a more experienced trainer to keep them from turning into a ratty-haired bite machine.
12. Chow Chow
It’s got a thick double coat of luxuriously soft fur that just begs to be cuddled and snuggled.
They’re got tiny triangular ears and a face with shorter hair, giving them a sort of lion’s mane (the Chinese term for the chow chow translates to “puffy-lion dog”).
It has straight legs, a square frame and a distinctive bluish black tongue that it’s not afraid to use on faces.
The breed has remained largely unchanged since it was used in ancient China as an all-purpose working dog. It is among the closest breeds in terms of genes to the grey wolf, believe it or not, and that hardiness and aggression was useful when hunting, herding, and guarding.
The chow’s temperament has softened immensely in the centuries since it accompanied the Mongolian armies as they pushed into Europe in the 13th century. It’s still a very protective dog however. It becomes very suspicious of strange people and pets.
It is a very well-behaved breed, capable of great patience, but it will leap upon any threat real or imagined with aggression. They are intensely loyal dogs, usually singling out one or two individuals as a personal favorite, and they can become very overprotective as they age.
13. Shar Pei
The breed was struggling in its native country after the Communist Revolution, prompting Chinese businessman Matgo Law to smuggle two hundred of the dogs into America to preserve the breed.
Sadly, most Shar Peis are descended from these two hundred, leading to several inbred traits and a host of accompanying health problems.
Shar Peis are thought to be descended from the Chow Chow as both share a blue-black tongue. They have bulldog-like facial wrinkles that were originally bred into the dog to help it hunt in thick underbrush, as well as to fight boar.
It found popular usage in dog fighting rings in China, and unfortunately some of that aggression continues in the latest incarnation. They are very territorial and stubborn dogs, requiring a patient and firm trainer to keep them socialized.
Their Chinese name is “sand skin”, referring to their notoriously rough coats, which can cause scrapes and irritation on some humans if the dog rubs against them too hard. The breed is slowly making a comeback but inexperienced trainers would be wise to leave this one to the experts.
They are considered by many experts to be one of the most intelligent dog breeds, second only to the border collie in terms of trainability and intuition.
They were originally bred in Germany as hunting dogs, their distinctive curly, hypoallergenic coat being very useful keeping water and muck off their skin while they retrieved dead fowl from ponds. But it was the French that created the tiny, cuddly version we all know and love today.
They’re a favorite of dog shows the world over, winning top honors in both looks and problem-solving ability, and they interbreed easily. There’s very little a poodle can’t do.
Unfortunately, having such a smart dog as a member of the family can lead to boredom. Poodles still retain many working dog traits and have been known to slip into old behaviors like pointing out prey and herding other dogs. If left alone too long they become extremely restless and will get resentful and aggressive.
The toy varieties have a notoriously high pitched bark and tiny, sharp teeth that they’re not afraid to use. Fortunately, poodles are among the most trainable dogs and even a moderately skilled trainer can usually teach them how to behave with minimal effort.
15. Shiba Inu
They sport soft, short fur that tends to come in blond or reddish tones and a white underbelly that they love having rubbed.
The Shiba is a very old breed used by the ancient Japanese to help hunt up in mountainous terrain. They have strong jaws and a keen sense of smell and can be very independent, often charging far ahead of the rest of the pack.
Shibas are avid self-cleaners and can sometimes be seen to housetrain themselves. Their aloof nature makes them good companions for cats, but they are not afraid to get noisy and mean when the situation calls for it.
They’ve been known to emit a trademark “Shiba scream”, a high-pitched mix between a yip and a howl, when sufficiently threatened. The females are especially aggressive, especially against other dogs.
It is not an especially jealous breed but it has a strong drive to seek out prey and it does not appreciate other dogs’ competition. A Shiba is happiest when given plenty of room to run and jump, and the occasional downtime to do its own thing.
16. Boston Terrier
A compact and muscular little dog with bugged out eyes and high, front-facing bat ears. They have short muzzles and surprisingly large tongues that they love to use on just about anyone.
Their quick, trainable and don’t require too much space. There’s a reason the breed’s so popular in the US. Unfortunately they are subject to a slate of health problems, as is typical with pure breeds.
They are a brachycephalic dog, which is a fancy way of saying their snouts are very short. Sometimes their snouts are so short they cannot breathe. The dog has an awkward pant and frequently makes odd slurping noises while exercising, trying to get the mucus out of its tiny nose.
It’s also prone to cataracts and deafness, all of which can affect this usually pleasant dog’s demeanor. They are eager to please their owners, but sometimes they interpret that as scaring away dangerous relatives, squirrels and mailmen.
Like many small dogs, they were once used as vermin killers, and sometimes these behaviors can resurface in the pet varieties. They can become hostile to anything smaller than a mid-size cat and they should be socialized early if you plan on keeping other animals.
17. Skye Terrier
According to The Kennel Club, the Skye Terrier is critically endangered in the UK, with some experts claiming there are less than 40 years left to save the breed from extinction.
Like many terriers it found a home in Scotland. It’s one of the island’s oldest terrier breeds and though it didn’t originate there, it takes its name from the Isle of Skye.
According to legend, a Skye Terrier stood loyally by the side of Mary, Queen of Scots throughout her entire execution. It enjoyed great popularity up until the mid-20th century when its numbers declined sharply.
Like many ex-hunting dogs, the Skye Terrier reacts aggressively to other animals. Unlike other terriers which are known to play roughly but fairly, the Skye has been seen to go for the kill. It’s especially displeased with cats and will often continue barking at them long after they’ve fled.
The Skye Terrier is also one of the few dogs that requires less exercise rather than more. Too much exercise can cause the dog’s bone growth to become stunted and lead to limps and joint pain that will affect its disposition further. The best thing a trainer can do for the Skye is to teach it how to be calm.
They adore small enclosed spaces and fenced in yards, making them perfect for apartment dwellers and suburbanites alike.
They are toy dogs, made to be cuddled and groomed with regularity, sometimes professionally so.
The Maltese is a very prone to mats in its long, luxurious hair, and sometimes even regular combings aren’t enough to do the trick. Experts recommend blow drying your Maltese after a good wash and shampoo, although even then the dog will require professional grooming every two months or so.
The Maltese is a very playful dog, often bursting with energy when everyone else is ready for a nap. Even older Malteses can still outperform the young ones in terms of playful cheer. The unfortunate side effect of this is a generally sullen mood when they don’t get their way.
They can yip aggressively at small children who aren’t behaving interestingly enough and are very vocal when displeased. They can also suffer from separation anxiety so it’s best to get a dog sitter if you plan to be away for more than a few hours.
19. Bichon Frise
They are descended from poodles in the Mediterranean area and were popular companions for sailors.
As such, they love the water, and will often leap into pools or out of boats to retrieve some floating object or another.
They were rarely used for hunting but still possess a few preying instincts. It has been known to present whatever it finds in the yard to its owner, eager for a pat on the head.
The Bichon Frise is very even-tempered compared to the Maltese, but it still requires a certain degree of love. It can become jealous in groups of pets or children, demanding a significant amount of attention from whoever’s in charge. It likes to defend its yard from invading squirrels, people, leaves, and sometimes nothing at all.
Owners have noticed the dog barking at empty air more than once. The need to vocalize can be trained out early, and if exposed to children it will become a fast friend. It’s also hypoallergenic and does not shed, and it’s not as prone to health issues as many similar breeds, so you can expect to keep your furry, attention-seeking companion for many years to come.
Another British head of state, Queen Charlotte, was depicted in several paintings with her two prized Pomeranians, although the dogs in the picture are much larger than the diminutive toy dogs we have today.
It’s among the most popular dogs in the US, a favorite of city-dwellers who need to feed their dog on a budget.
Like many toy dogs, the Pomeranian is a known barker. It will sound off at the smallest external stimuli, treating each falling leaf like an invading threat. They don’t bite often but they will persist in barking at strangers long after everyone’s settled down to dinner and cocktails. This habit must be trained out of the dog early for the sake of everyone’s eardrums.
They are very intelligent and cute and able to use both traits to their advantage. They are not above emotional manipulation to get what they want, often barking, whining, or playing dead to provoke more human attention. They’ve also been known to sneak into cupboards and closets, and they can leave a trail of destruction while teething.