In the U.S., about 4.7 million people get bitten by dogs in a year. About 800,000 of those bites result in some level of medical care. This might seem a little bit scary, but the fact is that while people do get bitten, it is possible in most cases to avoid it.

Avoiding a dog bite involves understanding why dogs bite in the first place.

Why do Dogs Bite Humans?

Dogs are intelligent, social, domesticated animals. Dogs do not bite randomly (and not all dog bites are attacks). Here are some of the reasons why dogs might bite you.

Play Bites

Some bites happen when you are playing with a dog and the dog gets a bit over excited. Play bites are seldom serious, and either happen because the dog has momentarily forgotten humans don’t have fur and are a little more fragile, or out of pure accident (the dog was going for the toy and got your hand by mistake).

The best way to avoid play bites is not to play too rough with a dog, especially one you don’t know. Be aware of what the dog is doing. For example, some dogs will get excited and grab the same end of the tug toy as you, which can result in an inadvertent nip if you aren’t quick to get your hand out of the dog’s way.

Protective Bites

By far the largest reason for a dog intentionally biting a human is defense of themselves or others. A dog may bite if they feel threatened, if they feel their owner or a member of their pack (which can include their owner’s family, other dogs, and other pets in the household. A bitch who has unweaned pups can be particularly dangerous. Never approach a whelping bitch you aren’t in a very good, established relationship with. Leave it to the owner.

If a dog growls, they feel threatened and you should back down unless you have a very real reason to escalate things with the animal. If it’s not your dog, back down. Some dogs can be overprotective, for example, a dog may growl and threaten if a stranger approaches the stroller containing their owner’s baby.


A dog may bite or snap if startled or suddenly woken up. This is the reason for the saying “let sleeping dogs lie.” These are generally quick nips and the dog may not even be consciously aware that it took a chunk out of you. Also don’t sneak up on dogs (or any animal).

A scared dog might also bite. Abused dogs will bite because they are afraid, but biting is not unknown if a dog is scared of a situation. For example, some dogs might get nippy when fireworks are being let off in the area or during a thunderstorm.

Resource Guarding

Resource guarding is sometimes called “food aggression,” but this isn’t accurate as it can occur with resources other than food. A dog might guard a favorite toy, its favorite place on the couch, etc. In some cases protection of the owner crosses over into resource guarding (That’s my lap and you can’t have it).

Resource guarding has to be addressed with training; with an unfamiliar animal it’s best to leave it be. Unfortunately, some owners find resource guarding behavior amusing and let it happen or even encourage it.

Hunting or Herding Behavior

Breeds with a strong prey drive may chase and bite somebody (especially a strange child) who runs away from them. Herding breeds may decide they want to herd the children (or other dogs, or you, or birds, or…) In the case of herding dogs the behavior is often triggered by boredom (herding breeds tend to be very smart and need a lot of mental stimulation).

Pain or Illness

A dog who is in pain or feeling unwell may simply be grumpy, and if that’s not respected, sometimes they will bite. They might bite even the people they like because, well, they hurt and they’re mad about it. This is obviously more common in older dogs. Don’t approach a dog you don’t know that seems to be in distress.

As a note, older dogs that suddenly become more aggressive and start biting without warning may be suffering from canine cognitive dysfunction, that is to say dementia. Yes, dogs can get senile. Often, hyper-aggressive dogs with dementia are candidates for euthanasia due to low quality of life and the danger they present to others.

So, dogs bite for all kinds of reasons, but there always is a reason. Being bitten is not always the victim’s fault, but it can be. The best way to avoid being bitten by a dog is to learn the basics of canine body language so you can tell when an animal is upset.

How are Dog Bites Treated?

If the dog has not broken the skin, then generally no medical attention is required. You should seek medical attention if you didn’t know the dog, if the bite is deep and/or bleeding profusely, or if the bite shows signs of infection. Otherwise, you can provide first aid by placing a clean towel over the injury and elevating it until bleeding stops, then wash carefully with soap and water and apply a sterile bandage. Use antibiotic ointment every day.

If in doubt, you should seek medical attention. If the rabies vaccination status of the dog is unknown or the dog tests positive for rabies, you will need the rabies vaccine. Otherwise, you may need a tetanus booster if not up to date and a short course of antibiotics. In some cases, the doctor may recommend a tetanus booster anyway, just to be on the safe side. Larger bites may be sutured. In some cases a larger dog can do enough damage that plastic surgery is needed, but this is relatively rare.

The largest concern, however, is preventing a bacterial infection, which can happen even with a relatively mild nip from a small dog.

Again, dogs always bite for a reason. Those reasons may vary from situation to situation and dog to dog; it’s not always the dog’s fault. If it is not your dog, though, you may need a good lawyer to help you get compensation and your medical bills covered. If you own a dog, it is a good idea to get dog liability insurance to protect you if your dog does decide to bite somebody.