Posted by: Viktor Mar | 2013 June 19

Pets: What are the most aggressive dog breeds? A university study provides interesting insight

By Lorrie Shaw Community Contributor

Posted on Wed, Jun 12, 2013 : 8:45 a.m.


I’m always amazed to hear the preconceived notions that people have of dogs in general.

The one topic really makes me shake my head: The misconceptions of dog aggression — particularly when it comes to breed. In working with any number of breeds on a given day, I can attest that aggression is far less common than one might think.

The truth is, any dog can become aggressive. But there a handful of breeds that rise to the top when it comes to exhibiting this most-unwanted behavior, and the findings of a study done by researchers at the University of Pennsylvania will certainly make one stop and think.

In my experience, I can say that the study, published in an issue of the journal Applied Animal Behavior Science, a few years ago, reflects what I see on a regular basis: the breeds of dog that have a higher incidence of aggression, snapping or attempting to bite strangers, their own humans and other dogs tend to be small breed.

In fact, the top three, are in order — dachshund, chihuahua and Jack Russell terrier.

So, is it a Napoleon complex? Something else?

A researcher who worked on the study, Dr. James Serpell, says that smaller breeds may have a genetic predisposition towards aggressive behavior than larger dogs.

"Reported levels of aggression in some cases are concerning, with rates of bites or bite attempts rising as high as 20 per cent toward strangers and 30 per cent toward unfamiliar dogs," he noted.

The study included questioning 6,000 dog owners. Breeds that scored lowest for aggression included Bassett hounds, golden retrievers, Labradors, Siberian huskies.

It’s interesting to note that the Rottweiler, pit bull and Rhodesian ridgeback scored average — even below average for hostility towards strangers.

Greyhounds rated the most sedate.

One important note, citing the study:

Our results indicated that there are certain types of aggressive tendencies (territorial, predatory, and intra-specific aggression) that are not reliably exhibited during temperament testing using this particular evaluation process


One reason that these smaller breeds don’t make for noteworthy attention when it comes to any hostile behavior is clear: because of their size, a chihuahua won’t inflict the same amount of damage as a larger dog.

As an aside, I notice all too often that the signs that a small breed dog is conveying that they are uncomfortable with a social situation — sometimes because of their babyish size and appearance — can be overlooked.

Do owners of these breeds have a tendency to not have the same criteria in mind when it comes to teaching them self-discipline as they might for a large breed dog, like training classes?

There are many complex reasons, beyond genetics, surely.

In any case, it’s vital that we understand that every dog has the capacity to behave aggressively. More importantly, it vital to note that in most cases, they choose not to do so, just like us.

Tags: Lorrie Shaw, animals, dogs, pets

Lorrie Shaw leads the pets section for Catch her daily dog walking and pet sitting adventures or email her directly and subscribe to’s email newsletters.



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