Do Dogs Turn on Their Guardians?

Is aggression predictable?
By Karen B. London PhD, August 2009, Updated June 2021

[Editor’s note: This post was inspired by a comment from a reader identified as Lou to a post about a seizure of dogs in dog-fighting bust. Read the original post and the comment here.]


Everyone who has experienced aggression from their own dog deserves lots of sympathy and the sympathy I personally have for them is deeply felt. It's horrific to be hurt by an animal you love and even more devastating to see that animal hurt somebody else in your family.  It’s even worse when people feel blindsided by the incident. As a professional behaviorist and trainer, I’m aware that we need to do a better job of educating people about the red flags of potential aggression. Red flags exist but are not always picked up on. In 10 years as an aggression specialist, I've yet to see an animal truly “turn on” someone without at least a hint that trouble was brewing. However, there's no doubt that is how it feels to many people who are involved when it’s their own dog who injures them.

Naturally dogs with a bite history towards dogs or people have given a warning, especially if it was an attack that was prolonged and hard to stop. Such relentless aggression is a serious red flag that the animal has trouble with inhibition. Other typical warning signs include growling, barking, lunging, tooth displaying (especially with an offensive pucker), a tendency to get frustrated, difficulty calming down after getting revved up, going stiff, tongue flicking, charging at anything of interest, hard stares directed at another individual, facial expressions indicating nervousness or discomfort, becoming mouthy when in an aroused state, excessive sniffing of the ground in social situations, guarding food or toys and being fearful of people, animals, or any other object.


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Any of these signs, or even the general feeling that something is amiss warrant a consultation with a person trained to deal with serious behavioral problems in dogs. Such a person may be a certified applied animal behaviorist, a trainer, or a veterinarian who is board certified in behavior.

Stereotyping breeds to predict aggressive behavior is not useful or fair. The predictability of aggression based on a dog’s breed is highly overrated. The idea of breed bans or rejecting certain animals simply because their relatives (members of the same breed) have misbehaved bothers me. Certain breeds are getting more bad press than they deserve, and aggression is a stereotype that seems to stick, even if other generalities are fitting. For example, most people with a Pit Bull will laugh if I say that whenever I meet a lovely Pit Bull, I always want to warn people, “Pity the poor intruder who gets licked to death,” and it’s a common joke that Pits can’t hold their “licker.” And yet, most of what we hear about is Pit Bull aggression, not excessive licking. Rottweilers and Dobermans are also breeds that many people fear on sight without any actual data about the particular animal in question.

On the other hand, there’s no denying that certain lines of dogs that have been bred for aggression do exhibit it. Regrettably, aggression is easy to breed for if that is someone’s intent. However, it is critical to remember that not all members of breeds who have been bred for aggression are from lines with that sort of breeding history.

Over the years, the two most common breeds I have seen for aggression issues are Golden Retrievers and Labrador Retrievers. Are these bad dogs? Aggressive breeds? Of course not. They are just common breeds so I see them a lot. I rarely hear of a breed of dog without being able to recall at least one client whose dog of that breed had an aggression issue. Yet, I have met far more dogs from all these breeds with lovely temperaments than I have met individuals with aggression issues.  Have I met aggressive Pit Bulls, Rottweilers, and Dobermans? Yes, I have, but I’ve also met aggressive Poodles, Bichons and Greyhounds, just to name a few breeds. In my experience, aggression is far more predictable based on a dog’s previous behavior than on the breed.

I look forward to hearing other people’s perspectives on the predictability of aggression. This topic truly fits the criteria for a can of worms, and I personally consider vigorous debate to be more fun than a barrel of monkeys.

 Image: iStock

Karen B. London, Ph.D. is a Certified Applied Animal Behaviorist and Certified Professional Dog Trainer who specializes in working with dogs with serious behavioral issues, including aggression. Karen writes the animal column for the Arizona Daily Sun and is an Adjunct Professor in the Department of Biological Sciences at Northern Arizona University. She is the author of six books about canine training and behavior, including her most recent, Treat Everyone Like a Dog: How a Dog Trainer’s World View Can Improve Your Life