Aggressive behavior of dogs kept as companion animals: Classification and influence of sex, reproductive status and breed

AbstractData were obtained from a total of 245 cases of aggressive-behavior problems in dogs kept as companion animals. Aggression involved barking, growling and biting behavior. For each case, a home visit of one to several hours yielded a description of the sequences of aggressive behavior and the stimulus conditions in which they occurred. Eight major types of aggression were observed: aggression related to fear; dominance; possessiveness; protectiveness; predation; punishment; pain; and intra-specific aggression.The incidence of each type of aggression is presented. More aggression problems occurred in males than females, with dominance and inter-male aggression showing the greatest likelihood of occurrence in males. Fear-elicited aggression and predatory aggression were the least influenced by the sex of the dog. Tabulation of associations among these problems revealed that dominance and possessive aggression frequently occurred together, fear-elicited and intra-specific aggression frequently occurred alone, and many of the aggression problems were associated with non-aggressive problems related to fear (phobias) and anxiety. The data indicated that aggressive-behavior problems are widespread across many breeds and suggest some breed × problem interactions. Fewer instances of dominance aggression occurred in mixed than in pure breeds. A classification system, proposed to represent the functional sub-systems of aggression in the pet dog, is presented