If Your Normally Gentle Dog Turns Aggressive, This Could Be the Reason

If Your Normally Gentle Dog Turns Aggressive, This Could Be the Reason

Story at-a-glance -

  • Sudden aggressive behavior in even-tempered dogs is often a sign of an underlying painful condition.
  • According to a study published earlier in the year, good-natured dogs who grow aggressive due to a painful condition are more likely than normally aggressive dogs to hold their bodies in a defensive posture, have an aggressive episode during handling, and attack without warning.
  • An otherwise gentle dog that suddenly displays random episodes of aggressiveness needs to have a thorough veterinary exam to check for painful conditions like hip dysplasia.

By Dr. Becker

If your normally laidback, affectionate dog shows sudden, random signs of aggression, it could be that he’s feeling pain somewhere in his body. According to a new study1, dogs in pain are on edge and can react aggressively if they are touched.

Otherwise loving dogs can become violent from pain, and dogs that already have aggressive tendencies get even more aggressive.

"If the pet is handled when in pain, it will quickly act aggressively to avoid more discomfort without the owner being able to prevent it," says study researcher Tomàs Camps. "Dogs that had never been aggressive before the onset of pain began to behave in this way in situations where an attempt is made to control them."

Characteristics of Pain-Related Aggression

There are many factors that go into the making of an aggressive dog, including the mother’s health and well-being while she’s carrying the litter, how the puppy is handled during the neonatal phase, the age at weaning, whether the pup is appropriately and adequately socialized, diet, exercise, inherited traits, and whether the dog was trained using positive reinforcement techniques or active punishment.

However, the goal of the retrospective study, conducted at the Autonomous University of Barcelona, Spain, was to examine the main features of canine aggression brought on by a painful condition.

The subjects of the study were 12 primarily large breed dogs who were seen at the Veterinary Hospital of the Autonomous University for aggression-related problems during 2010 and 2011. The group included a giant schnauzer, Irish setter, pit bull, Dalmatian, two German shepherds, Neapolitan mastiff, Shih Tzu, bobtail, Catalan sheepdog, chow-chow and Doberman.

There were 11 males and one female, and all 12 dogs had been diagnosed with pain-related aggression. Eight of the 12 had hip dysplasia, though the specific painful condition did not appear linked to the type of aggressive behavior displayed.

The dogs’ owners completed a questionnaire to help determine in what situations the dogs were aggressive, their posture during an aggressive episode, the target of their aggression (usually the owner), level of impulsiveness (whether there were any warning signs prior to an aggressive episode), and the degree of aggressiveness exhibited before they developed a painful condition.

The dogs were categorized as to whether they were aggressive before they were in pain, or only after.

Dogs that were not aggressive prior to the onset of their painful condition were:

  • More impulsive (attacked more often without warning)
  • More often showed aggression as a result of being handled
  • More often held their bodies in a defensive posture

According to study authors, “These results suggest that previous expression of aggressive behavior has a major effect on the pattern of pain-related aggression in dogs.”

The study further emphasizes the need for diagnosis of painful conditions in dogs and effective treatment for those conditions.

If Your Dog is Suddenly Behaving Aggressively …

I strongly encourage you to make an appointment with your vet to have your pet examined. A normally peace-loving dog who suddenly develops random episodes of aggressive behavior is very likely suffering from a painful condition that he needs help with – and the sooner, the better.


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