A Retrospective Analysis of Dog–Dog and Dog–Human Cases of Aggression in Northern Italy

In this survey, a caseload of aggressive dogs (n = 170) was analysed to increase the available information about biting dog characteristics, contribute to risk evaluation and improve bite prevention tools. All dog data were collected from questionnaires completed by veterinary behaviourists in Northern Italy. All dogs were referred to them by public authorities to be evaluated and treated due to the incidence of one or more episodes of aggression. Between the two groups of human-directed and dog-directed aggressive dogs, significant associations were found: the dog-directed aggressive group inflicted significantly more severe bites (p < 0.01) and offensive aggression (p < 0.01), whereas defensive aggression was significantly more numerous in the human-directed aggression group (p < 0.01) and more significantly located in private homes (p < 0.01). No significant associations were found between the severity of bites and one or more specific breeds in either group. The prevalence of defensive bites in private homes in human-directed aggression indicate that owners’ understanding of their dogs’ behaviour and communication is fundamental to preventing aggression, and that owner education programmes are fundamental tools to reduce aggression risk factors and prevent aggression.

Translational models of adaptive and excessive fighting: an emerging role for neural circuits in pathological aggression

Aggression is a phylogenetically stable behavior, and attacks on conspecifics are observed in most animal species. In this review, we discuss translational models as they relate to pathological forms of offensive aggression and the brain mechanisms that underlie these behaviors. Quantifiable escalations in attack or the development of an atypical sequence of attacks and threats is useful for characterizing abnormal variations in aggression across species. Aggression that serves as a reinforcer can be excessive, and certain schedules of reinforcement that allow aggression rewards also allow for examining brain and behavior during the anticipation of a fight. Ethological attempts to capture and measure offensive aggression point to two prominent hypotheses for the neural basis of violence. First, pathological aggression may be due to an exaggeration of activity in subcortical circuits that mediate adaptive aggressive behaviors as they are triggered by environmental or endogenous cues at vulnerable time points. Indeed, repeated fighting experiences occur with plasticity in brain areas once considered hardwired. Alternatively, a separate “violence network” may converge on aggression circuitry that disinhibits pathological aggression (for example, via disrupted cortical inhibition). Advancing animal models that capture the motivation to commit pathological aggression remains important to fully distinguish the neural architecture of violence as it differs from adaptive competition among conspecifics.