A Finnish study encompassing some 9000 dogs has demonstrated that fearfulness, age, breed, the company of other members of the same species and the owner’s previous experience of dogs were all associated with aggressive behaviour towards humans.
The findings—published in Scientific Reports—can potentially provide tools for understanding and preventing aggressive behaviour.
Aggressive behaviour in dogs can include growling, barking, snapping and biting. These gestures are part of normal canine communication, and they also occur in non-aggressive situations, such as during play. However, aggressive behaviour can be excessive, making the dog a physical threat to both humans and other animals.
The canine gene research group active at the University of Helsinki surveyed connections between aggressive behaviour and several potential risk factors with the help of a dataset encompassing more than 9000 dogs, a sample from a larger dataset from a behavioural survey dataset of nearly 14,000 dogs.
The study investigated aggressiveness towards both dog owners and unfamiliar human beings. Dogs were classified as aggressive if they growled often and/or had attempted to snap at or bite a human at least occasionally in the situations described in the survey.
“Dogs’ fearfulness had a strong link to aggressive behaviour, with fearful dogs many times more likely to behave aggressively,” doctoral researcher Salla Mikkola from the University of Helsinki said.
“Moreover, older dogs were more likely to behave aggressively than younger ones. One of the potential reasons behind this can be pain caused by a disease. Impairment of the senses can contribute to making it more difficult to notice people approaching, and dogs’ responses to sudden situations can be aggressive,” Mikkola added.
The study found small dogs are more likely to behave aggressively than mid-sized and large dogs, and that male dogs were more aggressive than females, regardless of sterilisation, also that the first dogs of dog owners were more likely to behave aggressively compared to dogs whose owners had previous experience of dogs.
The study further indicated that dogs that spend time in the company of other dogs behave less aggressively than dogs that live without other dogs in the household, and that some breeds are more consistently aggressive than others, probably due to genetics.