Breed Differences in Canine Aggression

Over the past few weeks, I've been thinking a lot about a mantra that I read a lot in news articles, from rescue sites, from commentors defending pit bulls on various websites, etc. The mantra, and if you've been around "pit bull" rescue people for very long at all you've heard it: "Pit Bulls aren't people aggressive, they're dog aggressive."

Is this true?  And if true, what is the severity of this truth?  And what implications (if any) are there?

Last year, three researchers, Deborah L. Duffy, Yuying Hsu and James A Serpell, got together and published a scientific paper on dog breeds and aggression. And when they looked at aggression, they looked at four different kinds of aggression: Aggression toward the dog's owners, aggression toward strangers, aggression toward other known dogs, and aggression toward unknown dogs.

The research paper also has a great intro that talks about the reason for the study to be to analyze a correlation between "breed" and "aggression" -- and why "traditional" approaches of doing this based on dog bite statistics are dramatically flawed.

The research is based on completed questionaires based on the Canine Behavioral Assessment and Research Questionaire (C-BARQ).  And while the researchers admit that as with many studies, there is some research bias involved as there is some sample bias and some bias that would go into the respondent's responses -- but I will say the overall results pass the sniff test of not being complete BS.  I wouldn't want to base all of my decision-making on the results, but I do think they provide an interesting look at how dog breed may or may not influence "aggression".

The study shows reports on 33 different breeds of dogs -- based on these breeds being the ones that they had a large enough sample size to provide accurate data.  All "pit bull" breeds were grouped into one "pit bull" category, so does not account for behavioral differences among the different breeds in the category.

Stranger Directed Aggression

A couple of breeds appeared really high in this category with Dachshunds and Chihuahuas leading the way. A few other breed, Australian Cattle Dogs, Australian Shepherds, Bichon Frise and Doberman Pinschers (in that order) also pretty consistently scored above average.

Greyhounds and Siberan Husky's were by far the least-aggressive in this category.

The mean score for "pit bulls" was below average on this type of aggression -- while the high end of their spectrum was above average (as it was for 22 of the 33 breeds) -- their overall scores were below average.  The closest comparison for "pit bulls' in this category are Great Danes and Soft Coated Wheaton Terriers -- with "pit bulls" scoring slighly lower than Boxers, Beagles and Poodles in this category.

Owner Directed Aggression

Most dogs showed no aggression toward owners, so the scale on this was significantly lower than others. However, there were 6 breeds here that were significantly higher than average in their aggression toward their owners: Dachsunds, Beagles, Chihuahuas, Cocker Spaniels, English Springer Spaniels and Jack Russell Terriers.

The four lowest breeds in this category were Rhodesian Ridgebacks, "pit bulls", Doberman Pinschers and Bernese Mountain Dogs. None of the dogs in these breeds scored above the all-breed average.

Dog Directed Aggression (unknown dogs)

The five highest breeds in this category (in order) are: Akitas, Dachsunds, Chihuahuas, Jack Russell Terriers and 'pit bulls'.  Other breeds that were above average include: Australian Cattle Dogs, Australian Shepherds, Border Collies, Boxers, Doberman Pinschers, English Springer Spaniels, German Shepherds and Soft Coated Wheaton Terriers.

The lowest breeds in this category were Greyhounds, Whippets, Collies, and Bernese Mountain Dogs.

Twenty two of the 33 breeds were above, or statisitically possibly above, average in this category.

Dog Aggression toward known dogs

Because these are known dogs, these numbers were again much lower than the unknown dogs:

Again, in order, the top 7 breeds here: Chihuahua, Jack Russell Terrier, Dachsund, English Springer Spaniel, "pit Bull", Beagle, Border Collie.

The lowest in this category: Labrador Retrievers, Brittany Spaniels, Golden Retrievers, Portuguese Water Dogs, Rhodesian Ridgebacks.

The pit bull's closest comp here is probably either the English Springer Spaniel or the Beagle.

Thoughts

Again, I would caution anyone from using any of the information as an end-all-be-all report on aggression by breed. Not only is the study subject to sample and survey bias -- but it is also important to note that any results do not indicated a causal relationship between breed and aggression -- only that a correlation may exist.  I think this is an important point still with this study.

That said, I thought the results were interesting enough to share and I do encourage people who are interested to purchase the study at the link provided above (cost is $31.50 -- I cannot legally make the study available for you).

As it turns out, based on this study, it turns out that there is some truth to the old addage that "pit bulls aren't human aggressive but are dog aggressive". In fact, there are few breeds that performed bettter in friendliness toward people -- particularly the dog's owners (which should help people understand why so many people are attracted to these types of dogs as pets -- they tend to be extremely friendly and loyal). It should also be noted that test scores from the American Temperament Test Society echo this notion that 'pit bull' breeds do well in temperament tests involving people.

As for aggression toward other dogs, it does appear as if 'pit bulls' do tend to be a little more aggressive toward other dogs than what is average. But I think it's important to note that they are not some weird statistical outlier here -- that are infinitely more aggressive than other breeds of dogs -- and in fact scored below several breeds of dogs in this category.

A slight tendency toward aggression toward other dogs is NOT something that is unique to 'pit bulls'. In fact, many breeds scored similarly to them in this category -- including many breeds people would not generally associate with being "aggressive".  The reality here is that there is a wider difference among dogs within a breed category than there is among most different breeds.

Based solely on this information, there is no scientific evidence that would in any way justify legislation targeted at specific breeds of dogs (any breeds), particularly 'pit bulls'.

The more we dive into what actual science has to say about dogs, the more we begin to realize how flawed all Breed Specific thinking is. That it is 100% based on emotion (often driven by media hyperbole) and not off of rational, scientific thinking.

Meanwhile, my hope also is that when 'pit bull people' talk about their dogs, they realize that the "dog aggression" they talk about is not something that is "unique" to 'pit bulls' -- but something that is somewhat common among many breeds of dogs. And that there is often much more difference in temperaments within particular breeds than there is between breeds.

Comments

[EmilyS]

do they define what "aggression" means?

I have a big problem with studies that use that word, especially if it's one of those "owner selfreporting" things.

It's such an incredibly loaded word.. behaviors that people may call aggressive may not be (and vice versa, of course)

[Brent Toellner]

Emily,

They based it off of the C-Barq qualifiers that seems to try to take judgment out of it (as much as is possible -- admitting that there will still be bias). I'll also admit to not being completely knowledgeable about C-Barq outside of what is in the study.

People were asked to report on a 0-4 point scale how their dog reacted "in the recent past" given a certain scenerio (and there are 101 scenerios). No negative reaction is given a 0. A snap, bite or attempted bite is a "4" - and then thinks like growling, barking, etc fall in the "1" "2" and "3"'s -- although those aren't well defined in this study but apparently are in the C-Barq test.

I think it is also important to note that even breeds that scored the highest in human "aggression" and dog "aggression" still averaged around a 1.5-1.7 -- so even within the breeds that scored the highest, the majority of the dogs in the test groups still scored way below what I would consider "aggresssive" -- which further indicates just how safe dogs are as a species.

I think the study is worth reading -- it does pass the "sniff test" IMO...but certainly isn't an end-all for the overall discussion.

[TEH]

The paper is worth reading and does support the fact that many dogs can be "aggressive". There is a German study (do not have the reference here right now) that shows similar result, the "pitbull" not being high on the tendency to aggression.

The large number of herding type dogs is interesting, something that does come up in bite reports. The following statement is from one of my "research advisers".....

“I think somewhere it would be valuable to mention the genetic work on dog breeds, showing that about 8 breeds are closely related to the wolf- this group includes several of the breds (sic) that often account for serious dog bites. In contrast, herding breeds are very unrelated to the wolf. This suggests behavioral differences that are genetic for certain groups of breeds. Our breed rankings based on veterinary interviews provide the same results as the genetic work.”

No references were given....and it took me a while to figure out what paper was being referenced. It is from the Science 2004 article on the genetic disposition of dogs. I disagreed with the statement re the herding dogs, and have known aggressive behavior in aussies and border collies. And the GSD certainly is represented in bite data, and this is a herding dog. Actually even the authors of the Science paper did not agree with the statement made, neither did a wolf expert.
Of course the basic problem with the statement is the assumption that the wolf is "aggressive". That then raises the question as Emily mentions define "aggression".
What it all comes to is the need for a better understanding of dog behavior......
something which I think very few of the human species does......
The whole topic is one for more study....and not to pigeon hole any one breed....

TEH

[Carianne]

I really like this blog post today. However, I think it is fair to say that when "pit bull" type of dogs are adopted out that the adopter should make the adoptee aware that most people will blame a "pit bull" dog even if the dog was not the aggressor, so try to keep them out of some scenarios, e.g. dog parks. Our pittie just passed her CGC and I still believe in not letting her loose with other dogs, other than our own. I really would rather avoid any undue media attention.

[Brent Toellner]

Carianne,

Thanks. I don't necessarily disagree with telling potential adopters that their dog won't get the benefit of the doubt in case of an incident. I do think that's very different than saying "don't ever take your dog to a dog park". I think it's very important for people to know their dog, know how it will react in certain situations, and not set their dog up to fail. I know that my dogs are generally fine around other dogs. However, I also know that if we were at the dog park and some unbalanced dog with rude behavior jumped on one of their heads (and it happens at the dog park) they would understandably not react well to that. And I'd just as soon not having that situation come up. So I prefer small play groups with other balanced dogs with owners I know (so that a mild skirmish, which does sometimes happen between dogs, doesn't become a life or death issue). It's more fun and relaxing for both me and my dogs.

And yeah, I prefer to stay out the media as much as possible :)

[Social Mange]

Thanks so much for sharing the information about this study.

[Julie]

An important point that you mentioned is that correlation and causation are not the same thing.

I think that owner expectation is extremely influential. When so many "pit bull" owners themselves believe that their dogs are "naturally" dog aggressive, one can easily imagine the implications for how those dogs are (or are not) socialized.

I completely understand rescue groups cautioning adopters about taking rescued "pit bulls" to dog parks or leaving them unattended with other animals. I expect that level of caution from anyone with a newly rescued dog. But I will never understand, or agree with, the idea of socializing "pit bull" puppies differently than you would any other dog. I know that plenty of people with all kinds of different dogs don't like dog parks- dog parks are a touchy subject all on their own. But if you restrict "pit bulls" from the experiences that you would freely allow any other dog, it isn't hard to see how "pit bull" could, in fact, become different.

Ultimately, I know that anecdotes do not equal data, but I have worked around dogs for far too long to think that dog-dog aggression is a "pit bull" problem.

[Fred]

Excellent post. I'm surprised this study hasn't gotten more notice. Well, maybe now it will.

[Christopher@BorderWars]

Fascinating!

I too wonder what the criteria are. For instance, I have no doubt that Border Collies are likely to be above average, if not in the top 10, for interactivity with other dogs. I don't think they're really fighters tough. So in this case I wonder what things qualify as aggression.

Having no data, just observation, I'd say that BCs are highly likely to stalk other dogs, perhaps herd them, and even nip. But I don't think they'd rank highly on serious injury inflicted to other dogs or people.

When I have a toy at the dog park, this changes. My BCs completely ignore other dogs, and the other dogs become fascinated with the intensity of the BCs. I've seen this provoke attacks from other dogs, as well as amorous advances. It's rather funny watching your BC in a crouch getting humped by some crazy other dog, and the BC not even caring.

One time, the dog mounted my BC backwards, so my dog was peeking through the other dog's hind legs waiting for me to toss the frisbee. Needless to say the Lothario went sailing once the frisbee was thrown. :c)

The intensity in BCs seems to bring out intense responses from other dogs.

[Jot Nirinjan]

I reaaaally want that article but am not rolling in expendable income, what was the percentage of "pit bulls" that were dog aggressive in relation to the total # in the study? I think that is a very important point to make: being more inclined to dog aggression than other breeds and the majority of the breed being dog aggressive are two COMPLETELY different things. At present, the wording that even rescues use leads the reader to believe that most APBTs are dog aggressive, which in my experience is not at all true (and these are dogs rescued from the kill list at my city's shelter - not responsibly owned and trained dogs) Are you at liberty to expose such infromation and dispell such myths?

[Brent]

Joe,

When they put the average score for all dog breeds, 'pit bulls' did score higher than average for aggression toward other dogs (both in strange dogs and known dogs) -- however, I think it's important to note that they were never some major statistical outlier like you would be led to believe -- in fact, in neither case were they the most dog aggressive breed of dog. So while it apppears that "trending toward dog aggression" would be some correct terminology -- "dog aggressive" probably isn't. In this case, 29 of the 132 'pit bulls' studied showed dog aggressive behavior (defined by the BARQ study as "Snaps, bites, or attempts to bite". That's an aggression score of a 4 on the BARQ test. The entire category of 'pit bulls' scored below a 1.5 -- so a large number showed no aggression at all.

[Brian]

I've been in law enforcement for over 25+ years and have taken my fair share of dog complaints, dog bite reports and general pet issues. I can tell you one thing, there was no single breed that stood out from any other. It all depends on the circumstance at the time, not the breed in my opinion. For the most part of these complaints, the owners should have and in some cases were criminaly charged.

Thanks for the discussion.

[Nimfa and my english springer spaniel]

Aren't dogs aggressive because they were provoked? If so, what are the most common things that make dogs behave unusual? I have a pitbull and every time he sees a ball, he won't stop barking and running. I really can't explain why.

[wordpress deveveloper]

This design is incredible! You certainly know how to keep a reader entertained. Between your wit and your videos, I was almost moved to start my own blog (well, almost...HaHa!) Wonderful job. I really loved what you had to say, and more than that, how you presented it. Too cool!

[Sue Pike]

Believe pit bull are all individuals with Individual personalities. We've owned 2 of them. First one well-trained from 4 weeks everyday. She was great under all circumstances. Second one well trained but occasionally needed to be crated.It was knowing each dog and being aware of their potential on or off leash. We are looking for an u aggressive herding dog now. We have horses, one burro, lambs, pigs,ducks, chickens, small dogs and cats so must fit in with our zoo. Young is probably good. Is collie best? Sue

[DB Goldstein]

Is there any study that reports the past C-Barq test scores of dogs that are documented biters? I'm asking if there is any evidence that the C-Barn test is actually predictive of aggression in dogs.