Recently, the heart-wrenching incident in Chengdu where a 2-year-old girl was bitten and left unconscious by a fierce dog has shocked the public. The history of dogs living alongside humans is the longest among all mammals, and companion dogs are often seen as domesticated breeds. So why, despite this long history, do we still find ourselves being attacked by dogs in seemingly unexpected situations? Is a dog’s breed the deciding factor in whether it will attack a human? In fact, aggressive behavior in companion dogs has long been a subject of study for animal behaviorists. While research on this topic remains limited, existing evidence suggests that our understanding and judgment of “aggressive dogs” may be based on misconceptions.
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Misconception 1: Avoiding “Aggressive Dogs” Means You Won’t Be Bitten
When a dog appears in our line of sight, most people might immediately begin to judge whether it’s an “aggressive dog” or a “well-behaved dog.” Some may even claim to “know” the dog’s temperament from a distance of several meters. If it’s the former, the assumption is that avoiding the dog will keep them safe. Truth 1: Any dog can bite. Unfortunately, dog aggression is not a “fixed trait.” Researchers from the University of Bristol in the UK, including animal behaviorists and welfare experts, conducted a survey of nearly 4,000 households with pet dogs. They analyzed risk factors for aggressive behavior in companion dogs when interacting with their owners or strangers. The study found that dogs living with humans cannot be classified as either “safe” or “unsafe.” Whether or not a dog displays aggressive behavior is more dependent on the specific situation at the time rather than the person involved. The researchers pointed out that a longstanding hypothesis in animal behavior is that a dog’s aggression arises when it feels threatened in specific circumstances and should not be considered a universal characteristic of the animal. The findings support this view, for example, a pet dog might bark, growl, or even bite its owner when the owner approaches its food or toys but remain calm when encountering a stranger in the home. On the other hand, some pets might be considered “monsters” by their owners but wag their tails happily when meeting strangers on the street. However, this does not mean that dog behavior is entirely unpredictable: aggression tends to escalate in stages when a dog is under stress or feels threatened. British veterinarians and clinical animal behaviorists have created a clear diagram illustrating the escalation of dog aggression based on reaction intensity in a handbook on canine behavior. Shepherd notes that although behaviors like sniffing, turning the head, sitting, or walking away may seem like benign responses, these actions could indicate the dog is experiencing discomfort. If the situation persists, its aggression may escalate, potentially leading to an outburst and injury. In this context, Casey emphasizes, “We need to understand that under certain circumstances, any dog can be aggressive. This is crucial to avoiding dog-related injuries.” She recommends not approaching an unfamiliar dog without first understanding the situation with its owner, even if the dog looks impeccably cute and harmless.
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Misconception 2: Certain Dog Breeds Are Aggressive Toward Humans
After dog attacks, the breed often becomes the center of public attention. Certain breeds (especially large dogs) or mixed-breed dogs with impure bloodlines are considered particularly dangerous. Truth 2: There is no evidence to suggest that a dog’s breed or lineage directly correlates with aggression. While certain breeds of companion dogs may have more recorded attacks than others, this could be due to the popularity of those breeds within victim communities, their use in fighting, or reporting biases. In 2014, the American Veterinary Association conducted a literature review of dog breeds associated with severe bites and found that German Shepherds, mixed breeds, Bulldogs, Rottweilers, and Jack Russell Terriers were most commonly involved. However, the review pointed out that the increased number of attacks linked to specific breeds often correlates with their popularity at a given time or regional prevalence. For example, the American Kennel Club saw a significant rise in Rottweiler registrations between 1990 and 1995, and shortly afterward, Rottweilers became the most reported breed in dog bite-related hospitalizations in the late 1990s to early 2000s. In Rome, Italy, Mastiffs are considered one of the most dangerous breeds, but there hasn’t been a disproportionate increase in bites by this breed in the region. Similarly, in some parts of Canada, sled dogs like Huskies are responsible for fatal attacks… Casey’s research supports this perspective. She and her colleagues compared the aggression levels of different dog breeds in three scenarios: with their owners, encountering strangers at home, and interacting with strangers outdoors. They found that while breed may influence aggression risk, assuming a dog’s aggressiveness solely based on its breed is inappropriate, as factors such as the dog’s origin, spaying/neutering status, age, training, and socialization history all play a role. Researchers emphasized that aggression is not necessarily linked to the dog’s inherent traits but may also be influenced by the owner’s breed preference and handling.
It is undeniable that a dog’s breed determines its size and strength. Although there is no evidence proving that large dogs are more aggressive than other breeds, when a bite incident occurs, the resulting injuries are often more severe. In response, many countries have opted to ban or restrict the ownership of certain breeds of dogs. However, some animal welfare researchers hold a different view. They argue that determining a dog’s fate based on skull width and leg length, rather than its behavior, ignores animal rights. More importantly, dog bans do not effectively reduce dog attacks. If authorities impose restrictions on certain breeds, it may actually increase their appeal— the more they are restricted, the more people are drawn to own them. Under such conditions, keeping these dogs only makes them more dangerous, as they may be treated more harshly, which increases the likelihood of aggressive behavior. Casey believes that the responsibility for “dangerous dogs” lies with us, the humans. The animal behaviorist uses a fitting analogy: in a car crash, high-speed cars cause greater harm, but we don’t ban high-speed cars from the roads. In modern society, the approach is to minimize the risk posed by drivers, regardless of the car they drive. Every driver must undergo training, passing both theoretical and practical driving tests before hitting the road. We also have a comprehensive set of traffic rules to reduce accident risks, supported by a series of laws that ensure enforcement. This logic can also apply to dog attacks. If humans choose to bring dogs into their lives, they should take responsibility for it.
