Aggression in Dogs
An otherwise gentle, friendly dog can behave aggressively when in pain. That’s why it’s so crucial to take precautions when handling an injured dog, even if she’s your own. A dog with a painful orthopedic condition or an infection might bite with little warning, even if the reason you’re touching her is to treat her. The improper use of certain pieces of training equipment, such as the pinch (or prong) collar or the shock collar, can inflict pain on a dog and prompt a pain-elicited bite to her pet parent. Male and female dogs are equally prone to pain-elicited aggression, and this type of aggression can occur in both puppies and adults.
Even though pet dogs rarely have the opportunity to reproduce, intact male dogs will still vie for the attention of females in heat, and females will still compete for access to a male. Intact male dogs sometimes challenge and fight with other male dogs, even when no females are present. Fighting can also erupt between males living together in the same household. In the wild, this is adaptive because the strongest males are more likely to attract females for breeding. Likewise, females living together in the same household might compete to establish which female gets access to a male for breeding. This type of aggression is rare. It’s observed most often in reproductively intact males and less often in intact females. Dogs who were neutered or spayed as adults may still show this type of aggression. If sex-related aggression happens, the dogs involved are usually at least one to three years of age.
Dogs are closely related to wolves and coyotes, both of whom are large predators, and pet dogs still show some classic canine predatory behaviors, including chasing and grabbing fast-moving things. Many dogs love to chase running people, people on bicycles and inline skates, and cars. They might also chase pets, wildlife and livestock. Some dogs bite and even kill if they manage to catch the thing they’re chasing. Predatory aggression is very different from other classifications of aggression because there’s rarely any warning before an attack. A predatory dog doesn’t growl or show her teeth first to warn her victim, so predatory aggression can seem to come out of the blue. Predatory behavior can be especially disturbing if it’s directed toward a human baby. Sometimes the sound of a baby crying or the movement of lifting a baby out of a crib can trigger a lightening-fast reaction from a predatory dog. Fortunately, predatory aggression directed toward people or other dogs is extremely rare in pet dogs.
Family Members, Strangers or Other Animals
Determining whom your dog is aggressive toward is essential to understanding her behavior. It’s common for dogs to behave aggressively toward unfamiliar people. Some studies report that as many as 60 to 70% of all pet dogs bark threateningly at strangers and act unfriendly when around them. Aggression toward unfamiliar dogs is also widespread. It’s less common for dogs to direct aggression toward family members or other pets in the home. Most problematic are dogs who are aggressive toward children, especially children in the family. Not only is aggression toward children exceedingly difficult to treat because of safety concerns, the likelihood that a dog with this problem will ever become trustworthy is slim.