How Aggressive Is Your Canine?

A recent study backs up Watson's experiences with golden retrievers. Evaluating surveys of two groups of owners, researchers at the University of Pennsylvania's Center for the Interaction of Animals and Society rated dog breeds on their levels of aggression. The study, accepted for publication in the journal Applied Animal Behaviour Science, indeed found that goldens rate among the least aggressive breeds. But the study also offers some somewhat unexpected conclusions when it comes to canine feistiness. You might be surprised to find where your dog's breed ranks.

Small Dogs, Big Attitudes
Using a survey called the C-BARQ (Canine Behavioral Assessment and Research Questionnaire), researchers collected results from both online respondents and a sampling of members of 11 breed clubs recognized by the American Kennel Club. Remember the saying "It's not the size of the dog in the fight but the size of the fight in the dog"? It turns out the surveys found two small dog breeds, Chihuahuas and dachshunds, rated high on aggression toward both humans and other animals.

"Initially, I was quite surprised by how aggressive these smaller breeds came out," says Dr. James Serpell, study co-author and director of the Pennsylvania center. "In smaller dogs, I think we tolerate higher levels of aggressive behavior," he says, adding, "the prospects of being seriously injured by a Chihuahua are small. Part of the problem with these little dogs is that they probably do live in terror a lot of the time because they are so small, and they are surrounded by giants - both humans and dogs."

How Other Breeds Rate
Akitas and pit bull terriers ranked high in aggressiveness toward other dogs, while Jack Russell terriers, Australian cattle dogs, American cocker spaniels and beagles were noted for aggression toward humans. Among the mellowest dogs were golden retrievers, Labrador retrievers, basset hounds, Siberian huskies, Bernese mountain dogs, greyhounds, whippets and Brittany spaniels.

"Interdog aggression is scarily high in some breeds," says Dr. Serpell. "Close to 30 percent of Akitas, for example, had shown serious aggression toward other dogs in the recent past," says Dr. Serpell. Indeed, says co-author Dr. Deborah Duffy, the amount of dog-versus-dog aggression reported by owners was alarming.

"What surprised us most was the percentage of owners reporting that their dog had bitten or tried to bite other dogs," says Dr. Duffy. "When we think of canine aggression from a public health perspective, aggression toward humans is typically what gets discussed. However, our study found that serious aggression among dogs is surprisingly common for some breeds, and this also presents a public health hazard because people can get bitten trying to separate dogs that are fighting."

Genetics likely plays a role in the aggressiveness of breeds such as the Akita, says Dr. Serpell. However, the researchers point out that these aggressive traits are often balanced by positive attributes, such as loyalty. Aggressive dogs, even the tiniest ones, tend to make terrific watchdogs, letting us know when strangers are around.