Aggression in Dogs
Dogs’ wild relatives are territorial. They live in certain area, and they defend this area from intruders. Wolves are highly territorial. If a coyote or a wolf who’s not part of a pack invades their territory, the resident wolves will attack and drive off the intruder. Some dogs display the same tendencies. They bark and charge at people or other animals encroaching on their home turf. Dogs are often valued for this level of territorial behavior. However, some dogs will attack and bite an intruder, whether the intruder is friend or foe. Territorial aggression can occur along the boundary regularly patrolled by a dog or at the boundaries of her pet parents’ property. Other dogs show territorial aggression only toward people or other animals coming into the home. Male and female dogs are equally prone to territorial aggression. Puppies are rarely territorial. Territorial behavior usually appears as puppies mature into adolescence or adulthood, at one to three years of age.
Dogs are a social species. If they were left on their own, they would live together in small groups, or packs, of family and friends. If one member of a pack is in danger, the others typically rush in to help defend that individual. This is classified as protective aggression because the dogs are protecting one of their own. Pet dogs may show the same type of aggressive behavior when they think that one of their family members or friends (human or animal) is in peril. Sometimes dogs reserve protective aggression for individuals they consider particularly vulnerable. A dog who has never shown aggression to strangers in the past might start behaving aggressively when she has a litter of puppies. Likewise, a dog might first show protective aggression when her pet parents bring a human child into the family. While this behavior sounds appealing at first glance, problems arise when the protective dog starts to treat everyone outside the family, including friends and relatives, as threats to the baby’s safety. Both male and female dogs are equally prone to protective aggression. Puppies are rarely protective. Like territorial behavior, protective aggression usually appears as puppies mature into an adolescence or adulthood, at one to three years of age.
Dogs evolved from wild ancestors who had to compete for food, nesting sites and mates to survive. Even though our pet dogs no longer face such harsh realities, many still show the tendency to guard their possessions from others, whether they need to or not. Some dogs only care about their food. These dogs might react aggressively when a person or another animal comes near their food bowl or approaches them while they’re eating. Other dogs guard their chew bones, their toys or things they’ve stolen. Still others guard their favorite resting spots, their crates or their beds. (Often, these dogs also guard their pet parents’ beds!) Less common are dogs who guard water bowls. Usually a possessive dog is easy to identify because she’s only aggressive when she has something she covets. But some dogs will hide their cherished things around the house and guard them from unsuspecting people or animals who have no idea that they’re anywhere near a valued object. Male and female dogs are equally prone to possessive aggression, and this type of aggression is common in both puppies and adults. For more detailed information about food-related possessive aggression and how to treat it, please see our article, Food Guarding.