Many dog owners don’t think much about aggression in dogs. Healthy, well-adjusted dogs don’t bite, growl, or snap at people or other animals. But not all dogs are healthy and well adjusted, and 4.3 million people are bitten by dogs in the United States every year.
The old saying that there are no bad dogs, only bad owners is not entirely true. Dogs are aggressive for a number of different reasons. And there are different types of canine aggression. Not all of them can or should be dealt with by pet owners.
Brain chemistry is a complex thing, and just as some people (like axe murderers) should not be wandering around free in society, so it is with dogs. Some dogs should never, ever be bred, sold, given away, or adopted out of shelters or rescues. If you go to a shelter or humane society and see a dog lunging, growling, and snarling at the gate, do not adopt it. And tell the shelter staff about it. Some dogs can’t deal with being in a cage for long periods of time and go "cage crazy" as it’s called in the humane community. These dogs should not be adopted and actually can pose a liability risk to the shelter itself.
Extended confinement is just one reason a formerly normal dog may start to exhibit aggressive tendencies. Others are abuse, pain, and extreme fear. However, some aggressive dogs behave that way not because of bad experiences or lack of socialization, but because of genetics.
For example, most terriers exhibit a very strong prey drive because they were bred to chase things. It’s what they do. However, an overdeveloped prey drive can become dangerous if the dog starts stalking the kids and biting them or killing the neighborhood cats.
If you are worried about your dog’s behavior, your first stop should be the veterinarian’s office. If the dog is biting because he is in pain, the vet can help. Thyroid conditions also can cause odd behavior, including aggression. At a minimum, the vet can spay or neuter the dog, which is a good idea since hormones trigger some types of aggression. If there’s no medical reason for the dog’s behavior, the vet also can refer you to a canine behaviorist.
You can help the behaviorist evaluate your dog by paying attention to details about the aggressive behavior. When does it happen and what does the dog do in response? Videotaping the dog also can be helpful. Behaviorists generally recommend behavior modification techniques to help mitigate or avoid problematic situations, but in most cases you have to remain vigilant. For example, if your dog has ever been aggressive around kids, you want to be very sure that the dog is never left alone with them.
If your dog is unpredictable, you need to get help immediately. Do not dump the problem on someone else by giving the dog away or taking it to a shelter. Safety for your fellow humans should always be your most important consideration.