Why Do Dogs Bite?

By Chyrle Bonk, DVM August 23, 2020

You’ve probably heard the old saying, “his bark is worse than his bite.” For most dogs, we are fortunate enough to never get the chance to find out. However, every dog, even the smallest, fluffiest canine companion, is capable of biting if provoked, and caution should be taken to help ensure that they never do.

Why Do Dogs Bite?

Dogs bite in response to something. They may bite when they feel scared, surprised, threatened, defensive, or when sick or injured. Dogs may also bite during play and some may bite simply out of aggression. In order to prevent dog bites, you need to be able to recognize these triggers and respond appropriately.

Every dog has the ability to bite if they have a good enough reason. Knowing what those reasons are can help you predict and prevent when a dog may bite.

  • Defense

Never mess with a mother dog or her puppies. Female dogs with a litter may bite if they feel they need to defend their pups. Dogs may also bite if they feel their territory, food, bed, or toys are in jeopardy.

  • Scared

Dogs may bite when they’re feeling scared or stressed. Ask any vet out there and you’ll see how many have been nipped at or bitten because a dog was uncomfortable or scared with a situation such as going to a veterinary clinic and being examined.

  • Threatened

Similar to being scared, threatening a dog with a weapon or even towering over them or using a loud voice can instigate a bite.

  • Startled

If you’ve ever woken a dog up suddenly from sleep or snuck up behind them, you’ve probably seen them jump. Just like humans, dogs can be easily startled and sometimes that surprise may bring on a bite.

  • Sick or injured

When pups aren’t feeling well or are in pain, biting may be their way of asking to be left alone.

  • Play

Puppies especially, but adults also, may bite during play. It may be due to over excitement, practicing new skills, or to let someone know they’ve gone too far.

Every dog’s tolerance for these causes is different. Some dogs may be quicker to bite than others when in the same situation. So don’t ever assume that you know how a dog will react to something.

Specific Situations When Dogs Bite

For a better understanding of what makes a dog bite, let’s look at individual situations and why a bite may occur.

  • Why Do Dogs Bite Playfully?

Biting during play may be due to excitement or due to a dog getting back to their roots and playing like a puppy again. A gentle bite, or mouthing, can also be a sign of affection. Your pup is trying to show you that they appreciate you.

  • Why Do Dogs Bite Other Dogs?

The reason that a dog bites another dog depends a lot on their relationship. If they’re normally friendly toward each other, then it’s most likely a playful bite. In addition, it is a way for a dog to express a warning if one dog is aggravating the other dog or that they’re not feeling well. However, if two dogs aren’t normally friendly toward each other, then a bite may mean one dog is trying to defend their territory, which may include you, or they may be scared, nervous or stressed by the other dog.

  • Why Do Dogs Bite Strangers?

If a dog bites a human stranger, then it’s almost always out of fear or defense. Something about this stranger could make them nervous or scared or they may feel like they need to protect themselves or you.

  • Why Do Dogs Bite Themselves?

When a dog bites themselves, it’s not typically a bite as we know it. The bite is usually a nibble or even a gnaw. Most of the time, a dog biting themselves is their way of trying to relieve discomfort. The discomfort may be due to skin, muscle or joint pain. It can also be due to itchiness from fleas, allergies, or other irritations. Dogs may also bite themselves as a form of neurotic behavior. These dogs are usually anxious especially when left alone or if something has changed in their world.

Dogs will typically bite themselves most frequently on their paws and tail because these are the easiest places to reach and have a higher risk of irritation. For example, fleas like to camp at the base of the tail, and the joints of the feet are common sites for arthritic pain.

Why Do Puppies Play Bite?

Puppies bite during play because they are learning how to fight. Just like a sparring match between friends, play biting helps puppies learn how to fight without actually hurting each other. While our domestic dogs typically don’t need to learn how to fight in order to survive, it’s still a skill that most puppies want to master.

Sometimes that playful biting will extend to you, especially if you have an only puppy in the house. This is just their way of saying that they consider you a member of their pack and would like to test out their skills on you.

When Do Puppies Stop Play Biting?

When your puppy stops play biting behavior will depend a lot on them and also some on you. Some puppies never really grow out of it, especially if they are encouraged to play bite and nip either by humans or other dogs in their household. Plenty of adult dogs will still play bite when they’re wrestling with another dog. Some will even continue to play bite when they play with humans, it all depends on their training.

As a dog parent, you can control the amount of play biting by doing some simple training. Whenever your pup is biting and you don’t like it, stop playing. Reward them for playing nice and stop the play if it gets too rough. You can also try jumping up or crying out as if you are getting hurt to let them know that things need to become gentler. This will hopefully help prevent having an adult dog that thinks it’s okay to bite humans.

What To Do With An Aggressive Dog

No one wants to worry about having an aggressive dog, especially one that may bite unexpectedly. Aggression may take many different forms and can be caused by different stimuli. But whatever the case is, being around an aggressive dog will take some work.

Dogs that aggressively bite will benefit from socialization with other dogs and humans. Socialization helps dogs become more comfortable in a variety of different situations, making them feel less fearful and less stressed. Socialization is more easily done with puppies, but can work for dogs of any age. You can try to socialize your pup at the dog park, an obedience class, or by having visiting friends. Just make sure you’re in a situation where you can control your dog should they become uncomfortable.

When Should I Be Concerned About A Dog Biting?

No one wants to deal with treating a dog bite or being around a dog that may bite. You should be concerned anytime you feel uncomfortable with your pet’s behavior. If you constantly have to keep your pup confined when visitors show up or you don’t want them threatening the mailman, then it’s time to do something.

Also, if you have children or other pets at home that serve as an added biting stimulus, it may be time to seek help. Remember, puppies often play bite, so it’s important to start young in order to teach your dog that biting isn’t an acceptable behavior.

What Can I Do If I Am Concerned About My Dog Biting?

Again, socialization may work wonders for a dog that bites out of fear or stress. Exposing them to as many different situations as possible will help them be more comfortable with the unfamiliar. But if socialization isn’t working, then there are a few other methods to try.

  • When to use a muzzle

Muzzles are used as a way to control dog biting. However, they don’t do anything to change your dog’s reaction to things or aggression. Rather, they just provide a physical barrier between your dog and other animals or people. Muzzles can be used whenever the biting risk is high. For example, use a muzzle when going to the vet or when going to an obedience class.

Muzzles should not be used when it’s hot out or for long periods of time, especially if it prevents a dog from panting. They should also not take the place of some kind of training to curb your dog’s biting behavior in the first place.

  • When to see an expert

It’s never a bad idea to get your veterinarian involved when you have a biting dog. First of all, they can help rule out any medical reasons that a dog may be biting, such as pain or illness. They can also help steer you in the right direction for further help from a behavioralist.

If you’ve tried socialization and other at-home training to help ease your dog’s biting, an animal behavior expert can help you further that training. They may be able to pin point the causes of your dog’s biting and help you and your dog overcome those causes. With methods like desensitization training and others, they can help change the way your dog responds to stimuli that causes them to bite.


Biting in dogs is a natural behavior that is used in play and to protect themselves. However, when it comes to our furry best friends, it’s a behavior that most of us would rather not see. In order to prevent your dog from biting, it’s important to understand the reasons that a dog may bite and how you can best change their response.

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