Canine aggression over resources like food or edible chews is commonly called food guarding or food aggression. Food aggression directed at humans can be relatively common in dogs. While it may be part of normal dog behavior, little is known about why some dogs show food aggression and others don’t.
There is a longstanding belief in the animal welfare field that underweight or previously starved dogs are more likely than normal-weight dogs to show aggression toward a human who approaches while the dog is eating. The assumption has been that a dog who has experienced food scarcity will place a high value on food even after food is readily available to them. The ASPCA® tested this theory to determine its accuracy.
The study examined existing data from 900 dogs who were a part of criminal cruelty cases and brought into the care of the ASPCA between January 2012 and July 2016.
Each dog’s body condition score (BCS) on the nine-point Purina Body Condition Scoring System was recorded at intake.
Behavioral data was collected during standardized evaluations conducted by teams of animal behavior professionals who were Certified Professional Dog Trainers (CPDT) or Certified Applied Animal Behaviorists or Associates (CAAB or ACAAB). The dogs were given at least 3 days after intake to the shelter to settle into their new environments before their behavior was assessed.
The behavior evaluation was composed of multiple scenarios that simulated what the dog would experience in a typical shelter or home environment, including having a bowl of food or an edible chew item taken away. This study examined the data collected during the scenarios in the evaluation.
It’s important to note that, in general, the ASPCA recommends using multiple sources of data, collected in multiple contexts when making outcome decisions based on a dog’s behavior.
Of the 900 dogs in this study:
- 422 dogs (47%) were Underweight (BCS of 1 to 3)
- 418 were Ideal weight (46%), and 60 (7%) were Overweight. The categories of “Ideal” and “Overweight” were combined for analysis; thus, 478 dogs (53%) were Ideal/Overweight
- A total of 83 individual dogs (9.2%) were aggressive over the food, chew, or both
- Most food-aggressive dogs did not escalate beyond stiffening and growling, even though their face was physically pushed away from the food items
- Underweight dogs were not more likely to aggress over food, nor to display more severe food aggression
- The risk of bites due to food aggression in this population may be considered relatively low and was not predictable based on body condition
Food aggression does not appear to be an abnormal behavior caused by a history of food scarcity or cruelty and is likely within the normal range of behavior in dogs.
Also, this study found that food aggression is not linked to a history of food scarcity. This is potentially relevant to court testimony in cruelty cases. A defense attorney could claim that the lack of food aggression in a behavior evaluation is evidence that a dog did not suffer from inadequate food resources. The findings provided by this research should be sufficient to refute this argument in a court of law.
Additionally, applied animal behaviorists and veterinary behaviorists who are called upon to testify in cruelty cases or consult with private clients on food aggression may find this information useful.