Aggressive behaviour is affected by demographic, environmental and behavioural factors in purebred dogs

Abstract

Aggressive behaviour is an unwanted and serious problem in pet dogs, negatively influencing canine welfare, management and public acceptance. We aimed to identify demographic and environmental factors associated with aggressive behaviour toward people in Finnish purebred pet dogs. We collected behavioural data from 13,715 dogs with an owner-completed online questionnaire. Here we used a dataset of 9270 dogs which included 1791 dogs with frequent aggressive behaviour toward people and 7479 dogs without aggressive behaviour toward people. We studied the effect of several explanatory variables on aggressive behaviour with multiple logistic regression. Several factors increased the probability of aggressive behaviour toward people: older age, being male, fearfulness, small body size, lack of conspecific company, and being the owner's first dog. The probability of aggressive behaviour also differed between breeds. These results replicate previous studies and suggest that improvements in the owner education and breeding practices could alleviate aggressive behaviour toward people while genetic studies could reveal associated hereditary factors.

Figure 1

The effect of age, fearfulness, sex, and, body size on aggressive behaviour in the logistic regression analysis. (a) Older dogs had a higher probability of aggressive behaviour than young dogs. (b) Male dogs had a higher probability of aggressive behaviour than female dogs. (c) Small dogs had a higher probability of aggressive behaviour than medium-sized and large dogs. (d) Highly and moderately fearful dogs had a higher probability of aggressive behaviour than non-fearful dogs. Grey area (a) and error bars (b–d) indicate 95% confidence limits. N = 9270.

Figure 2

Probability of aggressive behaviour in 23 dog breeds or breed groups. Several breeds differed significantly from each other (Supplementary Table S2). Error bars indicate 95% confidence limits. N = 9270.