Preventing Dog Bites: Stop Dog Aggression Before It Starts

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By Dr Sophia Yin

A viewer of this video recently commented to me, “This dog’s not aggressive because the definition of aggression is that he has an intention to hurt. The dog is just poor and misunderstood.”

While it’s clear that, yes, this little Jack Russell Terrier was probably misunderstood by his previous owners who returned him to the animal shelter, the full definition of aggression, as described in “Nelson’s Biology of Aggression” textbook includes the fact that threats intended to make you go away are also considered aggression. Even setting the definition aside, while most people look at the first few snarls or snaps as a fluke because they are so infrequent, doing so is similar to responding to reports that your child has gotten into a fight at school while using a bat or knife as a weapon, by saying, “Well it doesn’t happen very often.”

With dogs, all snaps and snarls or signs of fear need to be taken seriously because with practice they can turn to overt aggression leading to a bite. That is, unless you take steps to understand and remedy the situation, the dog is not likely to get better. Rather, these dogs tend to get worse.

For instance take this common scenario, Mr. Blue states, “A friend came to the house and went to pet Fifi. Usually Fifi avoids people or barks but then warms up to them. She would never hurt a fly. But yesterday when my friend reached for her this time she lunged and bit. I don’t know why.”

Or the scenario may sound more like this, “We were walking down the street and we saw a cute Shih Tzu.  I asked the owner if my daughter could pet the little dog and if the dog was friendly. The owner said, ‘yes’. But when my daughter reached out, the dog backed up for an instant and then leapt forward and bit her. The owner was shocked and said to me,  ‘She’s never done that before.’”

In both of these cases the owners failed to read their dog’s signs of fear or to take in consideration that their past fearful or reactive response might progress. Instead of thinking or saying, “She’s never done that before,” a more appropriate thought would have been, “ I guess in the past I’ve just been lucky that she had never bitten YET!”

Dogs can respond to fear by fleeing, freezing or fighting. For many dogs, the only question is at what point will they decide that fighting works best. With this in mind, it’s important that when you see signs of fear or even if your dog already barks and lunges and nips, you should address the issue immediately instead of relying on luck.  And hopefully address it successfully before it turns into a bite.

How to Fix Aggression

Ideas of how to address aggression vary among dog trainers with some saying you should have the dogs face their fears, the way you would deal with a fear of speaking in public or making friends in a room full of strangers. For dogs it would involve something like placing them a room of people they prefer to avoid and hold them down to show them you’re in charge. This type of technique, where you introduce the dog to the situation or stimulus full force, is called flooding. The idea is that the dog should calm down instead of becoming hysterical.

This approach can definitely work in a small subset of dogs, just like giving a speech in front of an auditorium may cure some people of their speech fears. This method can especially work in those cases of dog aggression or fear that really are not that difficult—ones that even though they may bark ballistically or even bite, would do well if you just got them out in public a lot with really very little training other than making sure that they are somewhat controlled instead of pacing and lunging and barking.

Putting Yourself in the Animal’s Place Reveals the Pitfalls of Flooding

While some dog trainers would go with the method described above, veterinary behaviorists, Ph.D. behaviorists, and those who base their methods on the science of animal behavior favor a graded approach that relies on changing the pet’s perception of the event and training more appropriate responses. To really understand this approach, you first have to understand the nuances of treating fear. You must first put yourself in the place of a fearful pet. For instance, imagine you are afraid of spiders. Then, imagine how you would feel if spiders were allowed to walk right up to you. Even if the spider is harmless or a baby, you’d want to get away. Now imagine someone held you so that you couldn’t escape and even held your mouth so you couldn’t scream when the spider was so close you feel it’s course hairs. Undoubtedly, this treatment would help some people to improve.

Photo from Low Stress Handling, Restraint and Behavior Modification of Dogs & Cats (book & DVD). If you’re afraid of spiders you don’t want a spider in your face, even if it’s a friendly baby spider. Similarly, if dogs are fearful or uncomfortable with some unfamiliar people, approaching the dog can cause him to defend himself.

But it’s likely to cause others to get much worse. They may stop struggling, not because they’re no longer fearful, but more likely because they are catatonic; they have given up. Their internal emotional state of fear has not changed but they are now expressing it in a different way, more like a possum playing dead. When you look at it from a more empathetic perspective, it’s pretty clear. Animals, including humans, respond to fear by fleeing, fighting or freezing and remaining very still. When fleeing and fighting don’t work, freezing is the only remaining choice.

As a result, the arachnophobe who’s held while spiders dangle in her face may finally freeze, but she will most likely still fear spiders even if she’s not allowed to show her fear when you’re around. You might think, “Well, no harm done,” but the repercussions down the road are that she becomes more fearful of spiders and that her fear may generalize to anything that reminds her of spiders—locations where she’s seen spiders, objects that she can’t immediately identify. Basically she may develop a post traumatic stress of sorts.

Low Stress Handling, Restraint and Behavior Modification of Dogs & Cats (book & DVD). Holding an arachnophobic person down so she can face her fears and a spider approaches generally does not make the person feel better. They may eventually top struggling even though internally they feel scared. The traumatic event may even make them more fearful of spider.

Similarly with dogs, putting them into the scary or reactive situation and just holding them down may cause them to look better on the outside but feel more conflicted on the inside. They may learn to hide their signs of fear because acting out their fear gets bad results. Then down the road, when they are in a scary situation, they may no longer give a warning growl. Instead, when they can no longer handle the fear, they break it in a bite out of the blue. So the outward warning signs of their inward emotional state have been extinguished leading to a more dangerous dog.

What are Your Other Options?

If flooding dogs can have such detrimental effects, what’s your choice? For decades, scientists and psychologists dealing with such fears have been using a combination of two techniques: desensitization paired with what’s called classical counterconditioning (DS/CC) or desensitization paired with operant counterconditioning.

What do those fancy scientific words mean? They’re actually pretty simple.  Classical counterconditoning basically means you’re going to change the pet’s underlying emotional state, in this case from fearful to happy. Operant counterconditioning means you’re going to train more appropriate behaviors such as focusing and engaging in behaviors with you rather than barking, lunging, or being reactive around the scary people. Desensitization in essence means you’re going to start with the scary person far away or less threatening somehow and when the dog can deal with that level of scariness, the person moves closer or acts scarier.

Changing the Dog’s Emotional State (Classical Counterconditioning)

Now let me explain in a little more depth starting with desensitization and classical counterconditioning (DS/CC). For humans who were afraid of spiders traditionally, what would happen is they would work on some relaxation techniques and think happy thoughts about being in happy places so that they started out in a positive emotional state. Then you’d introduce the spider in a form that was not that scary. For some people that means a picture of a small spider or a cartoon drawing of one because a real spider would be too scary. Once the human could remain in a positive emotional state, the fake or real spider could be moved a little closer or made just a little scarier. The goal at each stage though is that the human does not feel fearful and that they can stay below the threshold of fear.

For dogs, instead of telling them to think happy thoughts, we pair the process with something they like, such as playing fetch or eating treats. For instance, the owners could  give the dog a rapid sequence of treats while the scary person was nearby and stop the treats when the person moved away. The continuous stream is important because the treats have to come fast enough to keep the dog in that happy state. If the gap between treats is too long, then the dog may start slipping into his fearful state. Alternatively the unfamiliar person can toss yummy treats continuously while staying far enough away that the dog is only associating them with happy thoughts. In either case once the dog is comfortable with the person at one distance, the person can move closer, or if the dog is comfortable with the person standing stationary, the person can start moving while treats are being delivered. The dog should be on leash or controlled in some other non-restrictive way if he has a history of lunging.

It seems like this process would take forever, but if you always stay under the distance or threshold that scares the dog and you make sure the environment is comfortable and the dog starts out hungry, and the person is careful to follow all of the rules of movement around the dog, the dog can actually progress quite quickly. For instance in veterinary hospitals that use this technique, dogs that were previously untreatable or that caused a ruckus each visit can often be handled in the span of just 5 minutes if the rules of modification are closely followed. For other dogs though, just like people with spiders, multiple sessions may needed.

Training Dogs to Perform More Appropriate Behaviors

The other approach that science-based trainers and behaviorists use is to train dogs to perform alternate appropriate behaviors. This helps to take the dog’s mind off the scary person or object. But the trick here is that the dog must enjoy the alternate behaviors since no matter what they will still be associating the scary object with an underlying emotional state. For instance some people recommend that if your dog wants to bark aggressively at a passerby you make your dog sit. The issue of HOW you get him to sit is important. If you make your dog sit by giving a choke chain or pinch collar jerk or use some other coercive method, the dog may sit but may associate the scary person or situation with pain or more negativity. Hence the dog may get worse.

Furthermore, if he’s still looking at the scary person, he’s probably still thinking of how scared he is. If, on the other hand, we train the dog to sit and look at us for rewards then the dog is learning to behave well and to associate the scary object with good things. Typically in all but the easiest cases, I recommend more than just training the dog to sit. I like to engage the dog in more exciting/fun behaviors to get his mind focused on fun interactions with me. That is, I’m distracting the dog but in a way that he forms a positive association with the situation.

The Better Your Technique, the Faster the Dog Will Progress

Realistically regardless of whether you choose to just put the dog in a positive emotional state or to train fun behaviors that are incompatible with barking, lunging or acting aggressive/fearful, there is technique involved that can speed the process. And the exercises often involve more than just training the dog in the fear-inducing situations. For instance, I generally start dogs off on my version of the learn to earn program where they learn to automatically say please by sitting for everything they want while owners simultaneously learn to communicate clearly with body language and movement. The ultimate goal here is that the dog develops a habit of looking to the owner for guidance so he’s more likely to look to the owner for help in the scary or aggressive situation. The owner is learning how to direct the dog better so that the dog understands exactly what the owner wants. (For detailed instructions on my version of the Learn to Earn Program, read Perfect Puppy in a 7 Days: How to Start Your Puppy Off Right. This version is good for both puppies and adult dogs).

In any case, if you’re trying to work with your own dog and not clearly getting good results, it probably means you need help from someone who can coach you. If your dog has actually bitten someone or you have little control you should seek the help of an applied animal behaviorist, veterinary behaviorist (, or a trainer they recommend. Ideally, find someone who knows both the science and  who can coach you through the technical training skills. You can find links to trainers and behaviorists on my web site at:

Do you have a dog that you did not realize was a problem until it had bitten or nipped people? Share your story here.

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19 responses to “Preventing Dog Bites: Stop Dog Aggression Before It Starts

  1. Thank you Sophia for your videos!! I have a Yorkshire Terrier called Biggy. he is 10 months old and he is scared of unknown people and he bites them!! yesterday he did it to a man at the ariport. he goes crazy with people when I walk him and jumps at them to bite. however, with me, family and friends he is kind and friendly. he lets me groom him with no problems and he is very obedient. he comes when i call him and sits and everything. Same with other dogs. He has no problems, only with other unknown humans!! His brother Jen is an angel and very sociable and totally oposite. now I am going to try your techniques and see what happens!


  2. Dear Sophia,

    You have a way of explaining things that is clear, concise and to the point, and which I admire very much! This article, in particular, is outstanding!

    I often use the example of human fear of spiders when I explain to clients and class students why flooding, or forcing the dog to face his fears, might not be a good idea.

    I only wish we had more board-certified veterinary behaviorists in North America, particularly here in Canada! I carry a link to your site on my website, and often refer clients to specific videos or blogs on your site.

    Thank you for all you do, Sophia!

    Lisbeth Plant KPACTP
    Cowichan Canine Behaviour & Training Ltd
    Cobble Hill, BC, Canada

  3. Thank you so much Dr. Yin. The amount of valuable, practical information you provide for people is truly astounding and it is so accessbile it’s amazing. I am a dog trainer and behavioral consultant and I have experience with science based methods as well as dominance and pack theory as well as aversive training methods and I love that you seem to cover all the bases, mentioning the pros and cons of various training methods. Thank you so much and I’m very grateful.

    Paul Cottman

  4. Dear Dr. Yin,
    I am so grateful for the training techniques you provide. My boyfriend and I rescued a 1 yr old Jack Russell about 1&1/2 yrs ago. Soon after we realized this dog was badly abused. We have socialized him with our other dog and 2cats, as well as other people. He is great even with the babies that come to our home. Unfortunately we have a more difficult issue of aggression that occurs only at night and is directed towards me as well as the cats. Hondo will charge me teeth bared if I leave and try to re-enter my bedroom. I have been bitten more than once. He chases the cats but so far they have not been injured. We are hopeful that through modification we can resolve this issue as well. Hondo is too young to give up on and we know we have provided a much better home than he had before. Thank you for showing the videos that difficult animals can change. We will keep you posted on our progress!

  5. My vet gave me your website and I have worked with my beagle on his aggressive behavior on my own and with a very experienced trainer since he was a puppy and first exhibited biting behavioe. He is better, but still bites me occasionally and just nipped at the vet the other day. He is three years old. My problem is I can’t determine what causes the biting. I will do the same thing one day and he is great. He stands on command for his harness and sits right after and sometimes gets a treat for this behavior and always praise. He waits for me to allow him outside. Then other days, I was snapping the harness and he snarled and nipped at me. He immediately knows he is bad. I yell and let him know this is not acceptable and isolate him. He never aggressively attacks me and all bites seem to be when people’s hands are near his body. I can’t figure out how to use your method because I can’t figure out what causes it only sometimes. The fact that he does it to me is extremely concerning.

    1. If the dog gets aggressive only when people seem to touch his body, he could be in pain. It could be artgritis, toothache, something physical. I’d have a thorough vet check and blood work

  6. I have a 6 month old Beagle mix he is fine with my wife and I but he likes to bite my two boys (8 & 12) if they get to close to his face he will snip at them he has gotten their noses abs lips. Any suggestions

    1. Unfortunately, we cannot diagnose behavior problems over the internet. We do recommend that if you are having these issues, you see a certified Animal Behaviorist. We recommend the International Association of Animal Behavior Consultants, or the AVSAB, American Veterinary Society of Animal Behavior

  7. Neutering (or spaying) your dog is of critical importance for many reasons, including curbing any aggressive tendencies.

  8. I have a 4 yr old PRECIOUS Shih Tzu, but she is so bad at nipping at people that come into our apartment like the Nurse , and a Fed Ex man.
    She has also nipped two young boys that came over to play with my great granddaughter.
    When I take her outside, if there are anyone close to us or across the drive, she tries her best to get to them,and no matter if the dog is 10 times her size , she wants to get to them yelping her head off.
    I have her on a lease when outside and I have bought a sm muzzle but she rubs her face on the ground until it comes off.
    Thank you. Help is much appreciated ?

  9. Hello, my partner has an older dog, who’s anxious behaviour kicks in when I approach him after he has done something bad. This anxiousness involves turning his head to the side, slow movement, snarling and biting. The extent of my physical interaction with him in this circumstance is gently pushing down on his nose- (where the biting takes place) Otherwise I just approach repeating “Noo..” in a low stern voice. I have seen him use this nipping snarling response with others as a way of communicating his discomfort as well, including children. Now he is doing it with me too, I am wondering if there is a way of taming his knee jerk reaction to being uncomfortable.

    1. We’re sorry you are having this issue with your dog – that can be very frustrating. Included some links below that discuss canine aggression.
      We can also recommend our Perfect Puppy book & the Creating the Perfect Puppy DVD for more on training issues. Also you should rule out any medical issues that could be the problem, by seeing your vet. If the problem persists, we suggest you see a veterinary behaviorist. To find behaviorists in your area, please visit the American Veterinary Society of Animal Behavior website ( Under Resources, click on “Behavior consultants near you.” They will be able to better assess your situation and can give more detailed advice. You can also find others here:
      Hope that helps.

  10. My 7 yr old Yorkie/Pom just bit me so bad it bled just as I was reaching for his collar. A couple days ago he snarled and snapped when I picked up his toy. He also bit my Daughter as she was putting him down from her lap. He has always been loving and. Happy. What is happening to him and how should I handle it?

    1. I rescued a Lhasa Apso when he was 2 years old… he is now 4 and biting me and my partner AGGRESSIVELY! Oh yes, he is extremely loving ON HIS TERMS! I am legally blind and CAN NOT have him BITING ME.OMG I NEED HELP BEFORE HE …. has to go!

  11. I need help, my dog is a rescue, I got him at age 11 months, he is of mixed breed, I did a DNA and the results were retriever, ridgeback, collie, Rottweiler, Great Pyrenees, so he is a huge dog. He has started to lunge at people when on a leash, and recently lunged and bit. I need to break this, I’ve been putting him into a submissive state by laying him on his side but this does nothing to prevent it, it is after the fact. Please, if you can, advise

  12. Hi I have a shih tzu cross with King Charles he is nearly two and up ontill now he has never tried to snap at any one but he did it too my mother when she tried too put him too bed he was never like this could there be something wrong

  13. My parents have a 3 month old Australian shepherd puppy which just wants to jump, bite, latch on to clothing and pull. It isn’t “little puppy” nips that she does either. I have many bleeding bites to show for it. Our vet said we need to nip it and nip it right now and gave me your sight. It seems like she gets really excited and just would rather bite than play. You an be playing with her and she just clamps down on your hand or what ever other part of your body she can get ahold of. She was just to the vet yesterday and unfortunately she is still full of worms so she is on a new medicine for that. When she eats, she eats like she is starved. She constantly pulls mouthfuls of grass and eats it even dirt. If she gets a rock out of the landscaping it is hard to get it away from her as she snaps and bites. If we could just get her to stop biting it would be great. I am at my wits end with her.

  14. I have a Shih-Tzu who is 8 years old. I have noticed she has an aggression problem where she is not playful with other dogs and she doesn’t do well with kids. I went to my sister house for Christmas eve and my dog bit my nephew who is 5 years old and growled at my sister as she tried to pet her. How do I control her behavior?

  15. We have in our apartment complex a dog that bite my Scottish Terrier. The dog lunges at people. The dog is very aggressive and is getting more so. What is there that I can use to deter the dog and the woman ?

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