What Is Aggression, Anyway?

Learn how aggression fits into social behavior among dogs – and with humans. Why do dogs have so many ways to signal social conflict? How do “agonistic behaviors” help them survive? The Dog Trainer explains.

Jolanta Benal, CPDT-KA, CBCC-KA,
December 24, 2012
Episode #179

What Is Aggression, Anyway?

If you’re like most people, you’re pretty sure you know aggression when you see it. So here’s a pop quiz: Is it “aggression” when your 8-week-old puppy nips you? How about your adult dog chasing a rabbit he spots on an off-leash hike – is he being “aggressive”? Or what if Dogalini has a bone, Zippy approaches, and Dogalini curls her lip at him. Is Dogalini being “aggressive”? Bonus question: Is “aggression” a bad thing?.

It’s upsetting when our dogs bark, snarl, and lunge at other dogs, or when they growl at us if we approach them while they’re eating. Many people don’t mind if their Zippy chases a squirrel, but heaven forbid he should catch that squirrel and kill it. (And never mind that most of us eat animals too.) When you combine emotional distress with the wealth of misinformation available on the Internet, it’s no wonder we find it so hard to think clearly about certain kinds of dog behavior. And what we have trouble thinking clearly about, we also have trouble handling successfully. So I’ll try to unpack “aggression” for you.

Most social conflict is ritualized – its function is to avoid potentially catastrophic fighting, not to bring it on.


“Aggression” Isn’t the Same as Violence

One reason humans get so upset about aggression is that we equate it with violence. It might help to think about aggression in the larger context of what scientists call “agonistic” behaviors. These are behaviors related to social conflict. Among dogs, agonistic behaviors include not just barking, growling, biting, and the other behaviors we think of as aggressive, but also appeasing behaviors such as lifting a forepaw and rolling on the back to expose the groin and belly. In human terms, agonistic behaviors might range from smiling apologetically, to using lots of “I” statements when arguing with your spouse, to filing a lawsuit, to starting a war. And in both species, the most important thing about agonistic behaviors is that very few involve bloodshed.

Conflict is a fact of life among social animals. But serious fighting is risky, and not only to the loser. It uses up scarce calories – not so much an issue for our well-fed friends, but dogs have a long evolutionary history that precedes their career as pets. Injury makes it harder to obtain food and avoid danger, and the body’s self-repair needs more calories yet. That’s even assuming the injury is a minor one.

Real Fights Are a Big Risk for Both Winner and Loser


Because real fights are potentially catastrophic, dogs (and other animals) resolve most of their conflicts by a ritualized exchange of threat signals – a raised head, a direct stare, a curled lip, a growl – and appeasements – a turn away, a lowered body, an exposed belly and groin.

Rarely does conflict escalate beyond a doggy “argument,” one of those fast noisy exchanges that scare the heck out of the humans at the dog park but end with no harm done to the dogs except maybe a nick.

Agonistic Signals Are Communications

It’s important to remember that dogs don’t choose aggressive behavior as a substitute for being polite. Agonistic signals, whether appeasing or aggressive, are the only way nonverbal animals have of communicating certain kinds of social discomfort. Dogalini can’t use words to say “It worries me when you come near my food, so please back off.” Likewise, we can’t reassure her in human words, “Relax, Dogalini, and enjoy your meal; I just want to hang out nearby.”

Of course, this doesn’t mean that we have to endure being growled at – or worse, if Dogalini is particularly touchy. But, again, for social animals, agonistic behavior almost always functions to keep conflict ritualized rather than bloody. We often hear about an epidemic of dog bites, but consider how many millions of dogs live in close quarters with people and, unfortunately, how many people misunderstand or even mistreat their dogs. Serious injuries inflicted by dogs are surprisingly rare, because it’s quite an unusual Dogalini who’s declaring all-out war.

With that in mind, why escalate a minor confrontation by aggressing in return? Back off for the moment, and then use your giant human brain to find a qualified behavior specialist. You can’t talk to Dogalini in words, but you can teach her, through well-accepted, dog-friendly behavior modification techniques, that whatever situation she perceived as a threat really isn’t one at all.

What Is and Isn’t “Aggression”

And now to return to those examples I started with. The young puppy who nips is probably not aggressing. Play often includes behaviors, such as barking, chasing, and mouthing, that also happen during agonistic encounters. But instead of developing  into an argument or a fight, the behaviors are jumbled up and don’t escalate. (If play does turn into a fight, something’s gone wrong.) Young puppies are just learning about appropriate social behavior, including when and how to use their teeth in play. That’s “gently with other dogs, and not at all with people.” They learn dog rules from other dogs, and people rules from us.

As for Dogalini, is she aggressing when she warns off Zippy with a lip curl? I would answer “Yes, but it’s okay as long as neither dog escalates the conflict and they generally get along.” I might give my wife a dirty look if she goes for my dessert, but please don’t call the cops on us.

Last, that rabbit-chaser on the off-leash hike. I’m going to amaze you now. A dog who chases rabbits or squirrels is not showing aggressive or agonistic behavior. Not even if he catches them, kills them, and eats them. Maybe especially not if he kills them and eats them. Catching and eating other animals is predation – food-getting. It’s got nothing to do with social conflict at all; animals don’t have a social relationship with their food.

Which leads me to this extra bonus. Suppose your dog lives with cats and never tries to catch and eat them. But he does curl his lip if Kittychai comes near him while he’s got a bone. Yes, you guessed it – your dog has a social relationship with Kittychai, and that curled lip is a sign of a social conflict going on. Many a Kittychai understands Dog, but if yours doesn’t, you might want to work on defusing the situation. That, however, is a topic for another day.

For more about teaching and living with your dog, check out my book, The Dog Trainer’s Complete Guide to a Happy, Well-Behaved Pet.You can follow me on Twitter, where I’m Dogalini. I’m The Dog Trainer on Facebook, and you can also write to me at dogtrainer@quickanddirtytips.com. I welcome your comments and suggestions, and though I can’t reply individually, I may use them as the basis for future articles. Thanks for reading!

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Dog with Raised Paw and Dog with Food Bowl images from Shutterstock