Dogs walked every day by their owners are less aggressive. Dogs owned by women bark less at strangers. Heavier dogs tend to be less disobedient than lighter pets. Pugs, bulldogs, Shih tzus and other short-snouted breeds may be more badly behaved than medium- and long-snouted dogs, such as golden retrievers or the caramel-colored mixed-breed dogs popular in Brazil.
These are some of the findings of a study conducted by researchers at the University of São Paulo (USP) in Brazil. The study sample comprised 665 pet dogs of different breeds as well as mongrels.
The study—published in Applied Animal Behaviour Science—focuses on the correlations between aggressiveness and morphological, environmental, and social factors in the pet dogs analysed.
According to the authors, aggressiveness was influenced both by physical traits such as weight and skull morphology, and by social and environmental factors such as the type of household, the animal’s life history and the owner’s gender and age.
The findings confirmed the researchers’ hypothesis that behaviour is not only learned or influenced by genetics but also the result of constant interaction with the environment.
In the study, which was conducted during the COVID-19 pandemic, the owners of the 665 dogs in the sample completed three online questionnaires on themselves, the characteristics of their pets, the environment they lived in and any aggressive behaviour, such as barking at or attacking strangers.
“The owner’s gender was found to be a good predictor of behaviour toward strangers, in that absence of aggressiveness was 73 per cent more frequent among women’s dogs,” first author Flávio Ayrosa said.
The pet’s sex also appears to have influenced aggressiveness. “The likelihood of aggressive behaviour toward the owner was 40 per cent lower among female dogs than among males,” Ayrosa said.
“Snout length was even more significant: aggressiveness toward the owner was 79 per cent more likely among brachycephalic than mesocephalic dogs.”
The study also found that the heavier the dog, the less likely it was to display aggressiveness toward its owner. The probability of aggressive behaviour was found to decrease three per cent per extra kilogram of body mass.
The owner-related findings are not cause-and-effect correlations, Ayrosa added. “We found relationships, but it’s impossible to say which comes first.
“In the case of the factor ‘walking the dog,’ for example, it may be that people walked their dog less because the animal was aggressive, or the dog may have become aggressive because the owner didn’t take it out enough.”
