Social aggression is a natural, albeit scary, behavior in dogs. Much of it stems from instinct passed down through generations. Not all dogs are socially aggressive; many are dog-social and enjoy the company of other dogs. Others, however, feel the need to push their dominance over other dogs -- and humans.
Reason for Behavior
Social aggression stems from the behavior of dogs' wild relatives. Wolf packs have a social hierarchy in which their family packs all have a designated position. The alphas of the pack are highest, followed by lower-ranking adults and then juveniles. Contrary to popular belief, these social statuses are not often defined by fighting or aggression, although both sometimes occur when a challenge for dominance arises. Domestic dogs still have the instinct to form this hierarchy, and dominance is a status many dogs want to achieve. The dog with the higher status will oftentimes eat first, play first, receive attention first and be the decider on many activities. Not all domestic dogs show the need to be the dominant member. According to the ASPCA, male dogs show this behavior more than females, while purebreds are more prone to social aggression than mixed breeds.
Fights don't always ensue during displays of dominance. Some common behaviors in dogs asserting dominant behavior include putting their head or a front paw on the back of the lower-status dog, stiffening or low growls. In social aggression, the body posture is typically a stiff, upright position leaning forward with the tail out, not tucked.
Social aggression most often is the synonym for dominance aggression, although other types of aggression fall into the social realm. Territorial, possessive, defensive and fear aggressions can all be a part of the dog's life with other dogs -- and humans. Territorial aggression ensues when a dog or stranger comes into the dog's territory. Possessive aggression is protecting valuables such as food dishes or toys. Defensive aggression is feeling the need to defend himself against a bigger dog or human, while fear aggression is somewhat similar to defensive and comes on when the dog encounters a bigger dog whom it is afraid of.
Puppy socialization can curb a lot of social aggression in dogs. Socialization at a young age encourages your pooch to recognize that other pet dogs are friends and equals. Many of the ways that humans naturally react in a situation with a socially aggressive dog can actually make the behavior worse. Leash-tightening, raising your voice or tensing up during an encounter, or allowing your pooch to guard areas in the house can all reinforce negative aggression. Reputable trainers and behavioral specialists can help you and your socially aggressive pooch find the right path.