When is a Growl Not a Growl?

(Originally written for DogWatch, a newsletter for the general public from the Cornell University College of Veterinary Medicine)

My dog, a mixed breed, always does a lot of what I call “talking,” but a friend says this is growling and that I shouldn’t tolerate it. I find that hard to believe because my dog is the gentlest, best-behaved dog in the neighborhood. Should I stop the behavior or let it go?

Traditionally, all our knowledge of animal communication came from studying wild animals. In that realm, researchers quickly discovered that they needed to pay as much attention to the context in which the display occurred as they did to the display itself. For example, a lion’s roar could serve to alert other pride members of its location, warn another group of lions to stay in their own territory, or signal a competitor of the roarer’s intent to fight. The song spread of a red-winged black bird in which the bird spreads his tail, lowers his wings, and exposes his red epaulets may signal aggression to another male, but a desire to mate to a female.

Although our limited perceptual ability makes it impossible to detect many of the subtle differences that might distinguish these animal displays, this approach conserves energy compared to developing a new behavior to fit every need. In fact, we humans do the same thing in our verbal language. A simple phrase such as “Have a nice day” may convey completely different meanings depending on the speaker’s tone of voice. An upbeat tone might truly mean “Have a nice day,” but a surly one communicates, “I dare you to have a nice day since I’m so miserable,” whereas a sarcastic tone changes the meaning to “You are going to have a rotten day.”

In order to analyze dog communication in the past, scientists compared it to wolf communication. However, recent research indicates that dogs and humans have been living together much longer than previously suspected, perhaps as long as 135,000 years rather than the 14,000 years usually mentioned. Under these circumstances, contemporary dogs could owe more of their communication skill to their association with humans than wolves. Other studies indicate that while dogs have lost some of their problem-solving abilities compared to wolves, they have kept those that enabled them to survive in complex social environments.

When we put this altogether, two points emerge:

  1. We need to evaluate any animal’s behavior in the context in which it occurs.
  2. Displays such as growls that may mean one thing in a wolf environment might mean something completely different in a human-canine one.

So what are some of the messages that domestic dog growls communicate? The warning “Stay away” still ranks at the top of the list. When it occurs, other expressions such as a curling of the upper lip and stiff body posture often support the message. How seriously owners should take this depends on at whom the growl is aimed. Obviously such a display aimed at any person should never be dismissed based on the belief that the person did something to upset the dog. Rather, the details of the episode should be jotted down while clear in the mind and discussed with a qualified behaviorist or trainer.

In dog-to-dog communication, growling may function to keep the canine peace. In this situation, human interference may make the situation worse rather than better because it eliminates this valuable nonviolent way to communicate rank. Some dogs also make growling noises when they eat, and again context tells the story. A “talker” always makes noise while eating and doesn’t respond aggressively if the owner removes the food, whereas a food-guarder only growls when others are around and will respond aggressively. Still other dogs growl and snarl as they charge after and snag a thrown toy or play with one on their own, just as a child will make fierce noises when engaging in a battle with an imaginary enemy.

From these examples we can see that all growls are not created equal. By analyzing these displays in the context in which they occur and in terms of what they communicate about the human-animal relationship, we can eliminate the negative ones and enjoy what the others teach us about the richness of canine communication.