Do Dogs Know How Big They Are?

A study of body-size awareness in dogs seems to indicate that the answer is yes.
By Karen B. London PhD, August 2020
big and small dog

Who among us has not been stepped on by a dog who seemed completely unaware that her paws were on our feet? So many dogs do this that it’s hard to guess what kind of general body-awareness dogs have.

A recent study, “That dog won’t fit: body size awareness in dogs,” looked into this very question and found evidence that dogs do indeed have an awareness of their own body. Essentially, the scientists asked if dogs understand their body as an object of a particular size. If so, they should react differently to wall openings of different sizes.

As the researchers predicted, dogs’ responses to openings that were too small for them to pass through were different than their responses to openings that were large enough. Much of the study involved comparing the time it took dogs to approach the different-sized openings.

The dogs were tested on three sizes: smaller than their body; intermediate, or approximately the same as their body; and larger than their body. Dogs were slower to move toward an opening that was too small than they were toward one that was larger. After being tested with the smaller/larger openings, dogs were faced with an intermediate-sized space, one they could fit through, but without much room to spare. Not surprisingly, the time it took them to move toward this space was between the times for openings that were too small or much larger.


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I agree with the researchers’ prediction—that being aware of their own size would cause hesitation at the small openings and, to a lesser extent, at medium openings—but this isn’t the only explanation for the dogs’ behavior in this experiment. Even without familiarity with this particular experimental set-up, dogs’ experiences may have taught them what they can and can’t fit through. (As an example, watch a Mastiff run—or rather, trot—an agility course.) The results of the experiment may simply reflect some generalization by dogs from a lifetime of experience.

In other words, I’m not convinced that this experiment shows what the researchers think it does. Even though the results of the research are consistent with such an awareness, they do not disprove other possible explanations. Dogs have a lot of experience moving around in the world and going through or between things. Perhaps what this experiment shows is that they are capable of determining what they won’t fit through, which might simply mean they can see that objects and gaps are different sizes.

There is certainly evidence that dogs can be taught to have better body awareness based on experiences. In fact, there are many classes that offer to do just that, especially for dogs who compete in agility. By practicing a variety of skills—walking backward, weaving through a person’s legs, crawling forward and backward, putting front or back paws on a platform and walking backward up a stair or two—dogs improve their ability to coordinate their own movements in a variety of situations.

Many trainers have dogs practice walking over a ladder lying flat on the ground. Dogs who have practiced doing this are less likely to step on the rungs (especially with their back paws) than dogs who are new to the task.

As trainers, we commonly say that dogs need to learn where their back paws are, and many believe that dogs who have done so are less likely to stand on the delicate feet of their humans.

What does your experience suggest about your dog’s awareness of his or her own body?

Photo by Karolina Wv

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