Where the dog's aggressiveness comes from: the results of a new study

Researchers from the University of Sao Paulo (Brazil) have studied why some dogs are more aggressive than others. Or, in scientific terms, described correlations between aggressiveness and morphological, environmental and social factors, reports phys.org .The main conclusion of the study: the degree of aggressiveness is influenced by both physical characteristics (such as the weight and morphology of the skull), as well as social and environmental factors (type of household, animal life history, gender and age of the owner).

That is, the behavior of an animal is not only assimilated through education or determined by genetics, but is also the result of constant interaction with the environment.

The sample included 665 purebred and mongrel pets. Their owners filled out three online questionnaires, telling them about themselves, their pets, the environment in which they lived, and cases of aggressive behavior of dogs, such as attacks or barking at strangers. Here are some results of the study.

• The gender of the owner is a reliable predictor of behavior towards strangers: dogs whose owners are women are 73% less aggressive.
• The gender of the pet is also significant. The probability of aggressive behavior towards the owner is 40% lower in female dogs than in males.
• Even more important is the length of the muzzle: aggression towards the owner is 79% more likely in brachycephalic dogs than in mesocephalic dogs. (Brachycephalic dogs have a short muzzle and a rounded skull: these are Pekingese, shih tzu, boxer, Chihuahua, chow chow, sharpey, bulldogs, pugs and griffons. The mesocephalic skull is of medium length and width and is square or triangular in shape: these are retrievers, setters, etc.)
• The larger the dog, the less likely it is that it will show aggressiveness towards its owner. Every extra kilogram of body weight reduces the likelihood of aggression by 3%.
• Dogs that are walked regularly are less aggressive.
  
  At the same time, scientists note, conclusions related to owners are not cause-and-effect correlations. That is, there is a connection, but what is the cause and what is the effect is unknown. So, for example, it is possible that people walk a dog less because it is aggressive. And with the same probability it is possible that the dog has become aggressive, because it is rarely taken outside.

It is commonly thought that the aggressiveness of dogs is solely related to their breed, but in recent years this paradigm has changed: the behavior of an animal may depend on its age, gender, metabolism, hormonal balance and other factors.

The work was published in the journal Applied Animal Behavior Science.