Causes of Dog Behaviors & Aggression

A dog dealing with aggression may bite, snarl or growl, bare its teeth or snap. Causes of aggression are complex and are best determined and treated by a veterinarian or animal-behavior specialist. Visit your veterinarian to rule out any medical problems that may be contributing to your dog's aggression. Remember to be patient with your dog and never approach an aggressive dog as it may harm you as a result.

  1. Brain Chemistry

    • Your dog's mental make-up may contribute to aggressive behavior. According to k9aggression.com, just as brain chemistry causes depression or obsessive-compulsive disorder in humans, brain chemistry can cause agression in dogs. Medication and behavior modification can help this problem.

    Chronic Disease

    • Hypothyroidism (thyroid produces low levels or hormones), hypoglycemia (low blood sugar) or even epilepsy may result in aggression as a symptom of the disease. Veterinary treatment and maintenence of the disease should put a halt to agressive canine activity.

    Infection

    • Distemper and rabies are examples of contagious infectious diseases contracted by dogs. Aggression is a symptom of each of these diseases.

    Cancer

    • Cancer is a painful condition, and any dog in pain may exhibit aggressive behavior. Brain tumors alter the way the brain works, so a dog may become aggressive without even meaning to or realizing that he has.

    Head Trauma

    • Injuries to the dog's head cause swelling. Occasionally the swelling occurs in the brain, which affects the way the brain functions. This may cause aggression.

    Dominance

    • Dogs often feel the need to establish their dominant role in their "pack." Addition of new or strange dogs, family members or living arrangements may cause your dog to be more aggressive instinctually, as he tries to solidify his spot in his new pack.

    Fear

    • The Humane Society of the United States notes that dogs feeling threatened or scared may lash out aggressively to protect themselves. Your dog's perception of his circumstances may make him feel frightened even if the fear is unwarranted. For example, if you throw a ball for your dog he may interpret your raised arm as a sign that you want to hit him. He may then act out in an aggressive way.

    Territory

    • Dogs may react in an aggressive way to protect what they see as their own, or their territory. Territory may be food, a toy, a person, a place or so forth. If a dog feels that his territory is threatened, he may become aggressive to protect it.

    Frustration

    • Dogs that feel provoked by other animals or people become angry. If they cannot take it out on the animal or person that made them angry, they may redirect that anger and aggression towards someone who was innocent of it all.

    Behavioral Seizures

    • These seizures occur precisely in the area of a dog's brain that controls aggressive behavior. They alter the way that part of the brain works and make a dog act aggressively.

    Maternal Instincts

    • Puppydogweb.com states that dogs with puppies automatically become a bit more aggressive as a way to protect their young. A dog may react violently towards anything she sees as a threat to her puppies.