All dogs are capable of biting. It’s a natural behavior provided by evolution to allow dogs to protect themselves and hunt for meals. Domesticated dogs don’t really need to do either of these things most of the time but they are still capable of biting.
Most adult dogs will reserve biting as a last resort. They will give plenty of warning that they are considering biting and will avoid it as long as they can. The exception to this is dogs who have been punished for growling in the past. These dogs are likely to bite first and ask questions later. NEVER, punish a dog for growling! Dog parents are responsible for ensuring your dog never gets to the point where he feels he must bite. Supervise your dog’s activities so she always feels safe and never feels the need to bite.
Here are four reasons your dog might bite.
NOTE that I’ve left out puppy biting which is developmental (teething, learning bite inhibition, etc.). If you have a puppy whose biting seems excessive, see your vet first, then work with a positive trainer.
Excitement
Dogs use their mouths almost like humans use our hands. When dogs get super excited they can get “mouthy” or snappy. Offer a dog a 
yummy treat by holding it in your fingers and you may feel some tooth when he takes it from you. If your dog gets this excited about snacks, always offer them from an open palm.
Active (or rough) play can excite a dog to nip as well. A spirited game of tug can lead to your hand in your dog’s mouth. This often happens by accident but some dogs get excited enough for the win that they will grab your hand on purpose. When that happens, you both need to take a break from the game to calm down. Ideally, learn to notice the signs that your pup is getting over excited and take a break before any nips can happen.
Jake does both of the above so I taught him the cue “gentle” which I use to remind him to use a soft mouth when he gets excited.
Protection
Dogs can feel possessive of their people, food and things. Some breeds and individuals more than others. This behavior is called resource guarding and can become a serious problem if not nipped in the bud so if your dog displays guarding behavior, work with a positive trainer to eliminate it.
Resource guarding can start out mild with growls and escalate to biting. You often see this behavior among dogs living together in the same household. If your dogs are protecting their resources from each other, keep them separate when they have something of high value and consult a trainer for help.
Pain
When a dog feels ill or in pain, she may bite when approached or touched. It’s uncomfortable to be sick and many of us get cranky when we are in pain. Dogs have an instinct to hide pain and illness as a survival strategy so it isn’t always clear at first that your dog is suffering.
If your dog has any kind of sudden change in behavior, including growling, snapping or biting, your first step should be a thorough veterinary examination as a health problem can be the cause. Once pain or illness is ruled out, the next step is to look at behavior for a cause. A canine behaviorist and/or positive trainer can help you with this.
Fear
Just like humans, dogs have a fight or flight survival response and may bite when afraid. This manifests in a few different ways. If you try to pet a sleeping dog and he startles awake, he may bite instinctively. This is how children often get bitten.
Another common fear response is the reactive behavior often seen on walks such as barking and lunging at other dogs or people. This behavior can look ferocious but it’s rare for a dog to be truly aggressive. Most dogs would prefer to run away from something they fear. Leashed dogs don’t have that option so they have to “fight.” I put that word in quotes because what your dog is really doing in these instances is trying to appear quite frightening so the other dog will run away. Your dog doesn’t really want to get into a fight. Trainers call this a distance increasing behavior.
Jake during the height of his reactive days.
Reactivity can be resolved through training with a combination of desensitization and counter conditioning. It can take time but will make your dog’s life infinitely better to not experience so much fear. It will also make walks far more pleasant for you. Again, work with a canine behaviorist and/or positive trainer for help resolving your dog’s fear.
Just like people, dogs have a complex emotional life and are prone to both reasonable and irrational fears. Just like I might fight if attacked when I wouldn’t normally hurt a fly, your dog might bite when afraid when she is normally sweet as pie.
There is a lot of dog training that you can DIY by watching videos or reading a book, however, behavior caused by fear is potentially dangerous so I recommend starting with a professional positive trainer even if you then continue on your own.
If your dog is suffering from fear based issues, schedule a free 30-minute consultation with Ruth.
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