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Understanding Aggression in Dogs

Mean dogs are not just born that way

One of the most common reasons dogs wind up being relinquished to shelters, abandoned, or euthanized is aggressive behavior. For dog owners, canine aggression can be frightening, distressing, and baffling. One of the most important things we can do as dog owners is understand why dogs become aggressive, why punishment is not the answer, and whether there aren’t things we can do to help prevent them from becoming this way.

People sometimes think that aggression is innate—that certain dogs, and certain dog breeds, are just mean. But dogs aren’t just born mean. They become that way through a complex interaction of many factors—the majority of which are beyond the dog’s control. Some of the factors that can influence aggression include the conditions of the mother during gestation, age at weaning, early socialization, methods of training, diet, exercise, and genetics. But there is much we still don’t understand about aggression in dogs, and continued research is helping to give us a better picture. Not surprisingly, getting a handle on dog aggression involves taking a close look at dogs and the people who “own” and train them.

Here are some interesting recent studies which shed further light on dog aggression:

→ Outbursts of aggression are sometimes triggered by pain. A team of researchers from the Autonomous University in Barcelona, Spain carefully analyzed 12 dogs with aggression problems. They diagnosed all twelve dogs as having aggression caused by pain. Eight of the dogs had a hip dysplasia. Pain can cause aggressive behavior in an otherwise non-aggressive dog, and it can make an already aggressive dog have more frequent and more intense outbursts. It is particularly important to seek veterinary advice if a normally easy-going dog suddenly begins to bite or growl, and especially if an older dog shows behavioral changes. A painful medical condition is often to blame. The research was published in the March issue of Journal of Veterinary Behavior.

→ Contrary to popular opinion, pit bulls, German shepherds, and Rottweilers are not inherently aggressive. A dog’s breed has far less to do with aggression than owner-dependent factors such as how a dog is trained. According to a study in the Journal of Animal and Veterinary Advances, 40% of dominance aggression in dogs can be traced to the owner having failed to provide basic obedience training.

→ Aggressive training leads to aggressive dogs. This may seem like a no-brainer, but confrontational, even brutal training methods are still employed by many owners who want a disciplined dog. Unfortunately, these methods tend to backfire. According to a study done by researchers at the University of Pennsylvania, dog owners who used aggressive training techniques such as hitting their dog, growling at their dog, rolling their dog onto its back, or staring down their dog, often elicited aggressive responses from the animal. Many of these dog owners had come to a veterinary behaviorist for help with aggression problems in their dog. This study was published in the journal Applied Animal Behaviour Science.

→ Disagreeable people tend to prefer aggressive dogs. Researchers at the University of Leicester confirmed one of the common stereotypes about dogs and their owners: dogs often match the personality of their owner. The research team found that younger people who rank high on psychological tests for disagreeableness (unconcerned with the needs of others, suspicious, unfriendly, hostile) are more likely to prefer dogs with a reputation for being aggressive, such as pit bulls or boxers. Still, the results of the study also challenged some enduring stereotypes about dog ownership: they found no link between owning a dog perceived as aggressive and delinquent behavior. Nor did they find a link to status display or what researchers call “mating effort”: young men don’t buy tough-looking dogs in order to get girls. One of the findings that most surprised the researchers was that those who liked aggressive dogs tended to rank high on conscientiousness (being careful and reliable).

More from Jessica Pierce Ph.D.
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