Dogs are very much a part of the fabric of our society. And if we don’t live with them, many of us still care deeply about them. But one thing sometimes challenges our affection for dogs: when they show hostility despite our best intentions. It’s essential to manage hostile behavior to protect not only people but also dogs as guardians might respond by punishing their dog. If we could better understand how dogs come to display hostility, it could help ensure the well-being of both people and dogs.

This study, from Applied Animal Behaviour Science, aimed to find out what makes dogs more likely to be hostile, specifically toward strangers. It also looked at the factors that might escalate mild hostility (e.g., barking, growling, or baring teeth) into severe hostility (e.g., lunging, biting, or attempting to bite). Over 13,000 people answered the Canine Behavioural Assessment and Research Questionnaire (C-BARQ) between April 2006 and February 2013. They rated their dogs’ hostility in a variety of situations on a scale of 0–4. Overall, the study included ratings of 17,301 dogs.

Hostility toward strangers was more likely if dogs had a fear of strangers and if they were mildly afraid of nonsocial situations. Also, neutered male dogs were more likely to be hostile toward strangers compared to female or unneutered dogs. Dogs had a higher chance of being hostile if guardians adopted them from pet stores, friends, or relatives. This was also the case if guardians adopted dogs as puppies or adolescents. Hounds and sporting breeds were less likely to show hostility, while mixed and herding breeds were more likely to do so. Dog behavior develops through a complicated process. So it would be too simplistic to assume that the characteristics described above are solely responsible for dog hostility. Yet, these results could tell us which dogs have higher odds of developing hostile behavior toward strangers. This would mean we can design effective strategies for mitigating hostility or preventing it from emerging in the first place.

The researchers found a few qualities to be associated with severe stranger-directed hostility. A mild or severe fear of strangers was linked to a higher chance of severe hostility toward strangers. This was also the case for being male, and for being adopted from a shelter, family, or relative. Being a stray was also linked to a higher chance of severe hostility toward strangers. Sporting breeds were least likely to show severe hostility. The authors note that, often, external factors push dogs to show severe hostility. This may be, for example, when biting seems the only way to protect themselves. So, future research should examine how dogs with the characteristics described above are usually treated when they feel uncomfortable. This could help to uncover actual risk factors of severe hostility.

Future research could improve upon this study. For example, this study relied on guardians’ perceptions of their dogs’ behavior. These may or may not be reliable sources of information. But, this study could be a useful guide for anyone interested in ensuring that companion dogs are treated with affection and respect. This article helps animal advocates to promote a better understanding of how, ultimately, people play a significant role in shaping dogs’ behavior. When our dog behaves rudely around strangers, we should know that this, at least partly, reflects how we treat our dogs when they’re distressed.