Aggression

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.

When animals and people are afraid of something, they prefer to get away from that thing. This is called the flight response. But if escaping isn’t an option, most animals will switch to a fight response. They try to defend themselves from the scary thing. So a dog can be afraid of a person or another animal but still attack if she thinks this is her only recourse. A fearful dog will normally adopt fearful postures and retreat, but she may become aggressive if cornered or trapped. Some dogs will cower at the prospect of physical punishment but attack when a threatening person reaches for them. Fearful dogs sometimes run away from a person or animal who frightens them, but if the person or animal turns to leave, they come up from behind and nip. This is why it’s a good idea to avoid turning your back on a fearful dog. Fear aggression is characterized by rapid nips or bites because a fearful dog is motivated to bite and then run away. Sometimes the aggression doesn’t begin with clear threats. A fearful dog might not show her teeth or growl to warn the victim off. In this kind of situation, the only warning is the dog’s fearful posture and her attempts to retreat. Male and female dogs are equally prone to fear aggression, and this type of aggression is common in both puppies and adults.

Closely related to fear aggression is defensive aggression. The primary difference is the strategy adopted by the dog. Defensively aggressive dogs are still motivated by fear, but instead of trying to retreat, they decide that the best defense is a good offense. Dogs who are defensively aggressive exhibit a mixture of fearful and offensive postures. They may initially charge at a person or another dog who frightens them, barking and growling. Regardless of whether the victim freezes or advances, the defensively aggressive dog often delivers the first strike. Only if the victim retreats is the defensively aggressive dog likely to abort an attack. Male and female dogs are equally prone to defensive aggression. It’s slightly more common in adults than in puppies simply because dogs need to have some confidence to use this defensive strategy, and puppies are usually less confident than adults.

Animals who live in social groups, like people and dogs, typically live by certain rules in order to minimize conflict between group members. Canid species, including the dog, adopt a type of hierarchical order that influences which group members get first crack at food, the best resting spots and opportunities to mate. So rather than having to fight for access to valued things each and every time, those lower down on the totem pole know to wait until the higher-ups have had their share before taking their turn. These ordered relationships are frequently reinforced by displays of ritualized aggression. Individuals of high status use aggressive threats to remind the others of their place in the pack. The relationships between people and dogs who live together are certainly more complex than this simplified description, but it’s still important to know that a dog who perceives herself as high in status may show aggression toward family members. (This kind of behavior is sometimes called dominance or status-seeking aggression). This is why a dog might be perfectly trustworthy with one pet parent but react aggressively toward the other or toward young children in the family. Such dogs are often described as “Jekyll and Hyde” because, most of the time, they’re happy-go-lucky, friendly dogs. But if they feel that someone in the pack has overstepped his or her bounds, these dogs can quickly resort to aggression. An aggressive response is usually provoked by things that a dog perceives as threatening or unpleasant, such as:

• Taking food away
• Taking a chew bone, toy or stolen object away
• Disturbing the dog while she’s sleeping
• Physically moving the dog while she’s resting
• Hugging or kissing the dog
• Bending or reaching over the dog
• Manipulating the dog into a submissive posture (a down or a belly-up position)
• Lifting or trying to pick up the dog
• Holding the dog back from something she wants
• Grooming, bathing, towelling or wiping the dog’s face
• Touching the dog’s ears or feet
• Trimming the dog’s nails
• Jerking or pulling on the dog’s leash, handling her collar or putting on a harness
• Verbally scolding the dog
• Threatening the dog with a pointed finger or rolled-up newspaper
• Hitting or trying to hit the dog
• Going through a door at same time as the dog or bumping into the dog

Social aggression is somewhat more common in males than in females and more common in purebreds than in mixed breeds. Puppies are rarely socially aggressive with people, but they can be with other dogs, particularly littermates. Social aggression usually develops in dogs between one to three years of age.

It’s important to realize that the complexities involved in social aggression are poorly understood and hotly debated by behavior experts. Some believe that all social aggression is rooted in fear and anxiety, while others believe that it’s motivated by anger and the desire for control. When consulting a professional, make sure you’re comfortable with her treatment recommendations. If the professional’s suggestions consist of techniques for instilling fear and respect in your dog, such as alpha rolls, scruff shakes and hanging, there’s a very good chance that your dog will get worse rather than better—and you might get bitten in the process. Punishment may be appropriate, but only when it’s well planned and limited in application. The judicious use of punishment should always be embedded in a program that’s based on positive reinforcement and trust.

Dogs can be like human children in that when they get frustrated, they sometimes lash out with aggression. A dog who’s excited or aroused by something but is held back from approaching it can become aggressive, particularly toward the person or thing holding her back. For instance, a frustrated dog might turn around and bite at her leash or bite at the hand holding her leash or collar. Over time, the dog can learn to associate restraint with feelings of frustration so that even when there’s nothing to be excited about, she tends to react aggressively when restrained. This explains why some normally friendly dogs become aggressive when put behind a gate, in a cage or crate, in a car, or on a leash. Likewise, a dog who loves people can still show surprising levels of aggression when her pet parent lifts her up so that guests can enter or leave the home. Male and female dogs are equally prone to frustration-elicited aggression, and this type of aggression occurs in both puppies and adults.

Redirected aggression is a lot like frustration-elicited aggression with the exception that the dog need not be frustrated. Redirected aggression occurs when a dog is aroused by or displays aggression toward a person or animal, and someone else interferes. The dog redirects her aggression from the source that triggered it to the person or animal who has interfered. This is why people are often bitten when they try to break up dog fights. When a person grabs or pushes a fighting dog, the dog might suddenly turn and bite. Another example is when two dogs are barking at someone from behind a fence. Sometimes one will turn and attack the other. Male and female dogs are equally prone to redirected aggression, and this type of aggression occurs in both puppies and adults.

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.