In a 2006 study by the Cornell University, College of Veterinary Medicine, it was found that a percentage of dogs that had passed temperament tests and screenings were showing aggressive behavior after being adopted.
The researchers (Christensen, Scarlett, Camapgna, and Houpt) conducted phone interviews with the owners of 67 temperament tested and shelter adopted animals within 13 months of their adoption.
The questions focused on what behaviors the dogs were exhibiting, including jumping, soiling, separation anxiety, barking, and aggressive tendencies and their results found that the temperament screenings being used by shelters were not reliably revealing certain aggressive behaviors from territorial, intraspecific, food/resource, owner directed, and predatory aggression.
The researchers looked at several aspects of testing:
- Stimulus. What the dogs were exposed to during the temperament test included:
- Loud Noises
- Cat in a cage
- Removing food, toys, or rawhide
- Approach from a friendly dog
- Toddler sized doll
These were all administered by a single shelter employee in a new part of the building to look for a response.
- Age. The age of the dog when leaving the shelter was noted.
- Gender. The gender of the dog and the owner was noted.
- Time since adoption. The length of time that had passed since adopting was noted as more time could mean aggressive behaviors had longer to come to the surface.
The Basic Findings:
- Of the 279 dogs adopted from the shelter, only 67 families were reachable for interview, and only 66 completed the full questionnaire, so 66 owner/dog pairs were used for the findings.
- All of these dogs passed the shelter temperament test but upon a followup interview, 71.2% (47 of 66) showed behaviors consistent with aggression, which in this study included barking, lunging, growling, and snapping. When barking was not counted, the percentage of dogs showing aggressive behaviors (lunging, growling, snapping, and/or biting) was 40.9%
- Dogs were more likely to have moderate levels of aggression when looking at predatory and intra-specific (towards other dogs) aggression and low levels when looking at territorial aggression.
Research Limitations to Consider:
- Dogs may not show aggression in a shelter for various reasons, including exhaustion, no territorial attachment to the shelter and thus it is not worth defending, use of leashes, stress, and illness. This can lead to a dog with aggressive tendencies passing the temperament test and not showing aggressive symptoms until brought home.
- Owners may have recall bias or be unwilling to present certain information about their dog’s aggressive behaviors for fear of repercussions against their dog or themselves. This can lead to an inaccuracy in the reported behaviors of the dogs.
- A single veterinary technician may have a hard time catching all aggressive behaviors, especially in a scenario where they are hugging a dog and do not see a lip curling. This can lead to aggression being missed and dogs passing the temperament test.
How This Research Can Help You:
The testing system for finding well tempered shelter dogs is not perfect and anyone can end up with a dog that shows undesirable aggressive behaviors post-adoption. This research is not only designed to help shelters develop better testing protocols but also to expose adopters to the fact that they may need to seek behavioral advice somewhere along the line.
There is no shame in seeking help for your dog and in fact it will benefit everyone. Many dogs in this study, and dogs that are adopted in general, show low levels of aggression for one of the types of aggression (territorial, predatory, intraspecific, etc.) but this does not mean a dog can’t receive help and be rehabilitated.
If your dog is showing aggressive behaviors, speak immediately with a behavioral expert to determine the best course of action.