Why do dogs bite?

“It came out of the blue,” is the statement that most often accompanies headlines about dogs biting children. Typically the dog has always been “fine” around children and bit “without warning”. While it may seem that way to traumatised parents, these are erroneous statements. Dogs never bite without warning; unfortunately the warning signs go unnoticed by most pet owners. We’re going to take a look at why dogs bite, especially why they bite children, and what you can do to prevent dog bites from happening.

Why do dogs bite?

Dogs bite when they’re afraid, in pain or feel threatened.

Some dog breeds have heightened predatory instincts and after the initial fright, when they may snarl or snap, they may chase and attack a child who squeals and runs away. These breeds instinctively react in this way towards any “prey” that flees, including frightened children and small dogs and cats. Breeds with high prey drive include Rhodesian ridgeback, Irish wolfhound, German shepherd, Cane corso (considered one of the most dangerous mastiff breeds), Malamute, Australian Cattle Dog and many terrier breeds. This is just one of the reasons why you need to thoroughly research any dog breed that you want to bring into your household.

Dogs may also bite if they are naturally anxious (including separation anxiety and generalised anxiety), have a particular phobia (noise phobia) or have a medical condition, such as hip dysplasia and osteoarthritis.

Resource guarding is a common behaviour in dogs, ranging from mild to severe. Severe resource guarders can guard anything from the washing machine to a dropped pen. The most commonly guarded resources include food, toys, beds, and space. One of the most common causes of dog bites is not reading the signs of guarding behaviour.

Some dogs are not as cuddly as people would like them to be. They simply don’t like to be kissed, hugged and fondled. Unfortunately, those are the things we like to do to show our love and we also think it’s ineffably cute when our kids grab puppy’s nose and kiss her ears. All it takes is one hug too many and you’re in casualty waiting for your kid to get stitches.

Elderly dogs who are going blind and deaf may startle very easily (especially when in that special deep sleep that old dogs do) and lash out at whoever gave them a fright. Even a child who is not intentionally sneaking up on an old dog could find themselves on the receiving end of a nip.

When dogs are overexcitement they tend to lose all inhibitions and self-control (much like people). So when play gets over-the-top dogs may accidentally bite and bite hard.

Are there dangerous breeds?

That’s a loaded question because while some dog breeds are definitely dangerous when they bite, thanks to the damage their strong jaws can do, other breeds are more aggressive and more likely to bite. For example, a study in the journal Applied Animal Behavior Science reported that the most aggressive dog breed and the breed most likely to bite people (strangers and their owners) is the dachshund.

Behind that cute Daxie body and sad eyes lies a feisty spirit with dog bite statistics showing that one in five have bitten or attempted to bite a stranger and one in 12 have bitten or attempted to bite their owners.

Dynamite definitely comes in small packages as far as biting dogs are concerned, because Chihuahuas are the second most aggressive breed and Jack Russells the third most aggressive. In fact, according to the study, up to 30% of these smaller breeds are also quite happy to have a go at unfamiliar dogs.

The reason that bites by dachshunds don’t make headlines is because they aren’t usually serious, and owners tend to make light of the situation (cute little daxie flexing her muscles). They may pierce skin but some disinfectant and a plaster will usually cover the wound, unlike bites from larger breeds, like pit bulls.

The same study found that the least aggressive dogs include Bassets, Golden Retrievers, Labradors, Huskies and Greyhounds, while breeds that ranked below average to average on that aggression scale included Pit Bulls and Rottweilers. With this in mind, Pet Breeds.com found that the most dangerous dog breeds include:

Other studies have similar results, finding small- to medium-sized breeds to be far more aggressive than larger dog breeds traditionally associated with biting and aggression. For example, a study in Canada found that collies, spaniels and toy breeds are most likely to bite.

Headline-grabbing dog bite incidents, the ones that result in breed-specific legislation (including breed bans), are the ones that result in bodily harm and even death. With this in mind, the most dangerous dog breeds include:

About pit bulls

It’s worth noting that one of the reasons pit bulls are vastly over-represented in dog bite statistics, especially fatalities, is the fact that people can’t properly identify them and assume that most attacks come from pit bull-types. People have become conditioned to think that pit bulls are dangerous and bite, so when they witness a dog attack, the first breed they think of and identify is the pit bull, regardless of whether a pit bull was actually involved.

Another reason pit bulls are over-represented has to do with the type of people who usually own the breed. Because of their reputation, many pit bulls are owned by people who are involved in criminal behaviour, especially dog fighting where pit bulls’ skills are honed. When these dogs are rescued and rehomed, it doesn’t take much for them to resort to the skills they have learnt so well. Even successfully rehabilitated fighting pit bulls are a high risk for biting people.

It’s thanks to this element of society that banning dangerous breeds does not effectively combat dog biting incidents. After all, people who are willing to flout the law in some respects are probably not going to be fazed by a breed ban.

The American Veterinary Medical Association published the results of a study on Dog Bite Risk and Prevention: The Role of Breed, which essentially found that “Breed is a poor predicator of dog bites”. There are too many variables that come into play, including genetics, mother’s emotional and physically state during pregnancy, early life experiences as a puppy, training methods, gender, sterilisation, lifestyle, and the target (focus of aggression and biting).

Basically, it’s not as simple as blaming a breed.

Children are more likely to be bitten than adults

According to dog bite statistics in the US, between 60% and 70% of all dog bites are to children. The primary reason, according to one study, has to do with the dogs feeling threatened. Eric Goebelbecker pulled out what he considered the most important points from the study, namely that food guarding, resource guarding and territory guarding were responsible for just about half of all dog bite cases. Children in the family were most likely to be bitten over food guarding, while children outside of the family were most likely to be bitten over territory guarding.

Resource guarding was behind 61% of cases, while discipline measures were behind 59% of dog bite incidents. What this means is that punishing a dog for guarding or adopting aggressive postures does not eliminate the behaviour, instead it can aggravate the dog’s anxiety and insecurity and can eliminate all the warning signs so that it does appear that dogs “bite out of the blue”.

Dog bites are also worse for children because of their size because their faces are right in the firing line and if a dog lunges, they are sent flying, giving dogs the opportunity to stand over them and finish the attack.

How to prevent dogs biting children

The first way to stop dogs from biting children is never to leave children alone with dogs in the first place. In an ideal world, children younger than 8 years old (10 years old according to some experts) should never be left alone with dogs, but it’s not always possible to monitor an 8-year-old 24/7. If you have children younger than 8 years old, however, you should manage the environment to make sure they can’t accidentally end up with your dog unsupervised. Baby gates and play pens (play pens for dogs and kids) are invaluable in this regard.

Before you dismiss this as too much effort, think about all the possible signs of guarding that adults can miss, and then think how much less perceptive small children are. Dogs that are guarding a resource can warn you that you are getting close to crossing the line by:

Children usually miss all of the signals up to growling at which point they will either shout for mom or dad (making a sudden noise and startling the dog even more), squeal and run away (startling the dog and perhaps triggering a chase instinct), or smacking the dog on the nose, especially if they’ve seen mom and dad or any other adult do it. The smack doesn’t even have to land to trigger a bite, the simple act of lifting their hand signals intent and for a dog who is already on edge, it can be enough to make her lash out.

The second way to prevent dogs from biting children (and other people) is to learn how to read your dog’s body language and then teach your children how to read their body language too. This will not only help prevent your dog from biting your children, but it will also help your children protect themselves from being bitten by strange dogs, including strays. Body language that indicates your dog is unhappy or uncomfortable in a situation includes:

Many dogs display these warning signs for years without people taking notice and then one day, when they’ve had enough, they bite (out of the blue).

The third way you can stop dog bites is to teach your children to treat all dogs with respect. They need to learn how to interact gently and appropriately with dogs. This includes the dogs in your home as well as any dogs they are likely to meet when out and about. Children should always ask for permission before touching a stranger’s dog, especially if the dog is on lead.

You also need to teach children how to play appropriately with dogs. Overexcited dogs have very little self-control and if there is one thing children excel at, it’s ramping up dogs’ excitement levels. You can teach an older child to play with restraint or to recognise the signs of overexcitement and calm things down. But you will have to supervise play with younger children and step in and manage the situation if it looks like it’s getting too much for your dog to handle. Remember, some dogs, like staffies, get excited more easily than others, and will need closer monitoring.

The fourth way to stop dogs from biting is to understand that they can also have a bad day, so you need to be aware of what your dog has to deal with on a day-to-day basis. You might have the gentlest dog in the world, one who is patient with your children, who seems rock steady and wouldn’t hurt a fly. But all she needs is one bad day, when stressors stack up (called trigger stacking) and she gradually becomes less tolerant of irritations.

Casey Lomonaco likens it to losing at Tetris; the more things that go wrong in your dog’s day, the faster the puzzle pieces fall, the more out of control your dog feels and the more her anxiety increases – suddenly the screen is full, the game is over and someone is in tears. The stressors (puzzle pieces) don’t even have to fall on the same day; the game of Tetris can be getting out of hand for weeks before the final stressor sends your dog over the edge.

For example: Your 4-year-old has a fever and has cried all night for 2 nights, so your dog hasn’t had much sleep and is trying to assimilate the feelings of panic and anxiety that the rest of the family is feeling. Because your child is sick, your dog’s mealtimes have been erratic and she may be hungry and confused. She hasn’t been for a walk in two days and you haven’t had time to play with her or give her the love and attention she usually gets. So she’s bored and confused. Your patience is thin so you shout at her when she barks for attention or out of boredom. You shout at her when she brings her smelly, spitty toy into your sick child’s bedroom. Two days later, your child is getting better and you’re starting to feel human again but you’ve run out of dog food and have to cobble something together out of remnants in your fridge and it hasn’t agreed with your dog’s stomach. She’s feeling a little sick, she’s still sleep-deprived and confused and your 8-year-old has been running in and out of the house past her bed, shouting for you to play with him. He accidentally stands on her tail. The screen is full and she can’t take anymore. Game over.

Different dogs have different threshold levels. Some dogs could withstand all of the above and still be fine. Other dogs would have broken after the second sleepless night. This is why you have to know your dog and be aware of how life is treating her at any given point in time. If your household has been more chaotic than usual, you may have to manage her environment more. Give her space, give her more brain games, make some time for her, etc.

The fifth way to prevent dogs from biting children is to understand the difference between “fine” and “happy”. Many people think that their dogs are fine with children simply because they don’t see an obvious negative reaction, like growling. They don’t see any of the signs that indicate the dog is not “fine” and then the dog “bites out of the blue”. Dogs are, as a rule, incredibly tolerant and will put up with an awful lot before they resort to biting. Most families will be lucky and even if their dog doesn’t like children, they will tolerate them until they grow up and learn how to behave more respectfully.

A happy dog looks very different to a tolerant dog. Tolerant dogs have stiff body language, and their faces look tense. For example, their ears are flat and back, their eyes are wide and their mouths are pulled shut. A relaxed and happy dog has soft (squinty) eyes, the ears are loose and their mouths are open. Learn to tell when your dog is genuinely happy and when they are just tolerating a situation and take steps to manage the environment so your dog doesn’t have to tolerate more than is necessary.

Recognise the times when your dog is stressed, for example, when your kids’ friends come over to play, when you have family dinners, when it’s Guy Fawkes, etc., and take steps to minimise the impact and keep her comfortable.

Dogs and Babies has a great post on dog body language. Turid Rugaas has a great book on dog body language – On Talking Terms with Dogs: Calming Signals (£3.82 from Amazon.co.uk).

The sixth way to stop dogs from biting is to provide a safe place, a sanctuary, where no one, especially children, will bother them. A crate makes a great safe place for dogs who need to get away from it all, but some dogs choose their safe place, which could be under a tree, under a table or in a corner in the bathroom. Wherever your dog’s safe place, no one bothers her, on pain of death.

The seventh way of preventing dog bites is to muzzle your dog whenever you go out for walks. Always use a basket muzzle so that your dog can eat, drink and pant comfortably. You may have to do some muzzle training to get your dog used to wearing it. Many behaviourists use muzzles as interim measures. They deal with a symptom of a problem and not the problem itself.

Can you train dogs not to bite?

That’s a tricky question. Technically the answer is no. Biting is a natural dog behaviour; it’s not something you can untrain. However, you can give dogs an emotional head start by socialising them properly as puppies, by not putting them in stressful situations where their choices are limited and by teaching bite inhibition when they are still young.


During a puppy’s first 16 weeks of life it’s important to expose her to as many new people, things and places are possible – and to keep those experiences positive. The more success your puppy has of coping with novel stimuli, the better able she is to deal with novelty as an adult. This means the more positive experiences she has with different types of people the less likely she is to be reactive or defensive around people she’s just met. Even if you don’t have children and no one in your social circle has children, which is increasingly common these days, you need to socialise your puppy because children are drawn to dogs like magnets and our dogs need to know they can cope.

Bite inhibition and self-control

Bite inhibition is also something that you can teach your puppy. In an ideal world, puppies would stay with their moms for about 16 weeks, during which time she’d teach them appropriate doggy manners, including bite inhibition (using their mouths softly. You can teach your puppy bite inhibition using food and play.

Some great resources on teaching bite inhibition include:

Note: Good bite inhibition and self-control don’t mean your dog will never bite, but it may just limit the severity.

Obedience training

Dogs with a solid foundation of basic obedience training are more likely to be able to exercise self-control and your cues are more likely to cut through once their brains have exploded than a dog with no training. It’s important to work on strong recall, leave it and look-at-me exercises.

You can make your children part of the training. If they are old enough and coordinated and patient enough, they can help you train your dog directly. If they are still too young (younger than 12 years old), they can watch and you can teach your dog that good things happen in the presence of children. Your kids can also be a built-in distraction, so that your dog learns to stay calm and focused even if the children are playing football.

What to do if your dog bites someone

Hopefully, you have noticed that your dog is anxious, fearful, reactive or overexcited so you can contact a qualified animal behaviourist to help you with any problems before a bite occurs.

It’s not too late to contact a behaviourist after a bite. Depending on the context, the bite history, the severity of the bite and your willingness to put in the work, a behaviourist will put together a behaviour modification programme (BMP). The BMP may include ways to increase your dog’s mental stimulation during the day, including training. It may include a change in diet and, in some cases, it may even include medication, at least for the short-term. Most behaviourists will ask you to visit your veterinarian to eliminate medical issues.

Sometimes it’s best to rehome your dog. A lot of dogs who can’t cope in a household with several children thrive in childless homes or homes with much older children. It’s important that you realise rehoming your dog is not a reflection on you as dog parents. Sometimes it’s just the best option for you and the dog. Again, a behaviourist can help you make the decision and can even help you through the process.

In very few cases, euthanasia is the only option. It’s heartbreaking but it’s true, some dogs may be too traumatised by their history to ever be able enjoy any kind of quality of life. They are too fearful, too reactive, or their fighting instinct has been too well honed for them to do anything else but bite. In these cases, euthanasia is the kindest thing to do.

What to take away from this post

The most important points to take away from this post are:

Finally, you love your dog, so try to make any long-term decisions about your dog’s future based on what is best for her as well as your family.


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