Aggressive behaviours in higher vertebrates, particularly in the domestic dogs (Canis familiaris)

Unlike rhythmic activities such as feeding and reproduction, aggressive behaviour is triggered mainly by external stimuli and relational factors. The function of aggressive behaviour is to increase or maintain a certain distance between individuals, whether they belong to the same species or not. However, in social species forming permanent cohesive groups, aggressive behaviour may jeopardise this cohesion. Various regulatory mechanisms appeared during evolution: on the one hand, a gradation of the intensity of aggressive expression based on the animal's motivation and on the protagonist's response, and on the other hand, the development of submissive behaviour which, unlike avoidance and flight, provides an adapted response to aggression while staying close by. Both mechanisms reduce the negative effects of aggression on the group's cohesion. In carnivores such as Canis familiaris, a distinction should be made between aggression and predation, as they have opposite functions, i.e. maintaining distance or capturing, respectively. This distinction is corroborated by other parameters, such as the nature of the signals displayed, the presence or absence of an appetitive phase, and the cerebral structures involved. Given the unique interspecies relationship existing between man and dog, canine aggressive behaviour must be controlled with greater care than if it was directed solely at fellow members of the same species. To limit the expression and adverse effects of aggressive behaviour, the dog's individual emotional characteristics and some selected genetic traits must be taken into account.