You Say Tomato, I Say……..

One of the benefits of offering puppy classes is that we often have the opportunity to follow dogs from the early stages of puppyhood through adolescence and adulthood.

An example of this is a young dog named Sassy, who attended class with her owners, June and Mark. They completed our 5-week puppy course and then, a few weeks later, enrolled in  Basic Manners. When Sassy started puppy class at 10 weeks, she was already a highly energetic and bold little gal. Her owners were dedicated and experienced students who had owned several dogs of the same breed in the past. Sassy was doing great in class and her owners were attentive and receptive to the advice of the class instructors.

At AutumnGold, we do not promote puppy play free-for-alls, but rather pair up pups each week, matching according to age and personality. We call this the “puppy dating game”. Pairs are carefully introduced and play is closely monitored to ensure that both pups are comfortable and having fun. Sassy got along well with other pups and though very confident, usually showed appropriate greeting and play behavior.

That is, until we introduced soft toys into the mix……..


While rubber toys and balls had little value to Sassy, we discovered that small, plush toys were another matter altogether. Sassy grabbed the toy , positioned it between her paws, hovered her head a few inches above the prized possession, and froze.

We quickly tossed several high value treats on the floor near Sassy and when she released the toy and moved to gobble the treats, quietly picked up the toy. The episode led to a discussion with June and Mark about resource guarding behaviors and instructions for teaching Sassy to “leave it” and “give” using a variety of items at home. We also offered them the opportunity for in-home lessons outside of class to directly work on these behaviors. (They did not take us up on this offer).

Fast forward: First night of Basic Manners class, two months later.

Carla, the lead instructor for our puppy classes, welcomed Sassy and her owners to class. Consulting her records, Carla inquired “So, are you still seeing any resource guarding behaviors with Sassy?

Mark answered: “Resource guarding? Oh no, she does not have a problem like that. She is fine.”

Perplexed, Carla elaborated. “Oh. So Sassy will readily give up her toys to you?”

Mark: “Oh heck no! She is awful with her toys. She runs away with them and freezes and holds on tightly if we try to take a toy away. We can’t take anything away from her!”.


You say tomato, I say…… Trainers and behaviorists use the term resource guarding to describe either defensive or offensive behaviors and postures that a dog may use to maintain possession or control of a particular toy, place, or food item. It is generally considered to be an umbrella term that encompasses the entire spectrum of possessive behaviors – everything from avoidance to becoming still to full-blown aggressive displays. Some trainers make a distinction between food and non-food resource guarding behaviors and use the term food-related aggression or food-bowl aggression as a sub-classification. Pet owners, on the other hand, may or may not have any of these terms in their vocabulary. Rather, as in the case of Sassy and her owners, they may recognize their dog’s behavior to be unacceptable, but do not have a specific term to describe it.

The words that we use to describe behavior, especially for those of us who work with pet owners, are important because these terms influence owners’ perceptions and reactions to both the behavior and the dog. For example, the issue of whether to label the behavior discussed above as resource guarding versus possessive aggression is one that comes up frequently and seems to have no clear consensus among trainers. Recently, to explore this issue in more depth, a group of scientists did what scientists do – they studied it.

The Study: Researchers at the University of Guelph in Ontario, Canada, surveyed a group of canine behavior experts regarding the terminology that they use to describe dogs who guard various types of resources. A group of 85 canine behaviorists were invited to participate. Thirty-six responded and completed the on-line survey and 29 participated in a follow-up discussion board. The survey used several approaches to gather data. Open-ended questions asked participants to define resource guarding and possessive aggression and to describe the behavioral criteria that they use to identify and differentiate these behaviors. In the discussion period that followed, participants responded to statements and questions that arose from the survey and discussed details of  terms and definitions.

Results: The majority (66 %) of the behavior experts enrolled in the study preferred to use the term resource guarding. However, there was not complete consensus. About 1 in 5 experts (21%) preferred to use the term possessive aggression, 2 respondents said that they use both terms interchangeably, and (oddly), 1 person used neither term. Interestingly, when asked about the use of a separate term for food-related aggression, the majority said that the use of a separate term for this was not necessary. Reasons for terminology preferences included:

  • Avoiding use of the word “aggression”: A substantial proportion of behaviorists felt that inclusion of the word aggression in a descriptive term was not broad enough to encompass all forms of possessive behaviors that dogs can show (and that may be problematic).
  • Communicating with owners: Pet owner perceptions were an important consideration for many behaviorists. They stated that the terms possessive and aggression can be easily misunderstood by pet owners. For example, the term possessive may be construed as a dog competing for ownership of something and result in erroneous beliefs of competition (similar to problems with the term dominance) between the owner and dog. Others focused more on the word aggression, stating that  the use of this word could cause a misunderstanding of the dog’s motivation for the observed behavior.
  • Inclusion of all resource-related behaviors: Participants agreed that dogs can use a variety of strategies other than aggression to maintain control of valued items. These include avoidance, running away, rapid ingestion, and body blocking. Although owners are usually less concerned with these behaviors (see “The Many Faces of Resource Guarding“), they can be problematic, would be missed under the label of possessive aggression, and yet should still be included in a treatment program.

Conclusions: The authors concluded the paper with a concise definition for resource guarding: “The use of avoidance, threatening, or aggressive behaviors by a dog to retain control of food or non-food items in the presence of a person or other animal”.

Take Away for Dog Folks: As a trainer, I prefer the term resource guarding because it encompasses a full range of possession-related behaviors  that dogs may show and avoids the word aggression and all of the emotional baggage that comes along with it. However, I also realize that I also use the term possessive (not always with guarding attached to it), and that I have not been tremendously consistent with my own terminology.

For example, below is a sequence of photos depicting a range of possessive behaviors that dogs can show. I developed this series for a lecture that I teach about canine body signals. This series uses the terms possession and possessive, rather than “resource guarding”. In considering my own inconsistencies, I realized that one possible drawback of using both resource guarding and possessive aggression is that these terms miss normal and non-problematic possessive behaviors that dogs can show during play or when they are simply enjoying having a toy near them. I think it is important to recognize and address these behaviors on the continuum to avoid categorizing all possessive behaviors as being unwanted or problematic.

The first row of photos below depicts a few of these – a dog playing with a pine cone, two dogs playing possession games with a tug, and a dog simply resting with her head on a beloved green toy.

In the second series below, the dog on the left may be avoiding eye contact. She also could have been simply looking away when the picture was taken and is just enjoying her time on the couch with her yellow toy. The dog in the center photo and the dog to the far right on the other hand, both appear to be still/freezing, with the cattle dog throwing in a whale eye for good measure. These are of course, problematic behaviors.

And no one would misinterpret the signals being sent by the two dogs in the bottom row or dispute that intervention is needed to address these resource guarding behaviors.

So, trainers and instructors – What do YOU call possessive and resource-related behaviors when you are speaking with other trainers and/or when you are working with students? Do you change your terminology depending on who you are talking to? Do you have a preferred term – resource guarding vs. possessive aggression? Something else altogether?

Tomato or……? 

Cited Study: Jacobs JA, Coe JB, Widowski TM, Pearl DL, Niel L. Defining and clarifying the terms canine possessive aggression and resource guarding: A study of expert opinion. Frontiers in Veterinary Science 2018; 5:115. 10.3389/fvets.2018.00115.

Interested in Learning More about Canine Nutrition? Take a Look at the Science Dog Courses and Webinars!

Interested in learning more about dog training and behavior? See Linda Case’s newest book – “Dog Smart: Evidence-based Training with The Science Dog“!


One thought on “You Say Tomato, I Say……..

  1. I think of this as a matter of degrees and situation dependant, not an absolute. I’m looking at the low end of the spectrum. I have a Springer pup who is grabby and tends to drive my very laid-back Labs away from both food and toys. No barred teeth, growling or hostility. It’s like the older dogs are saying WTF, if she wants it that much, let her have it.


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