Behavioral characteristics of English Cocker Spaniels with owner-defined aggressive behavior

Information on the behavior of both aggressive and nonaggressive (control) English cocker spaniels (ECS) recruited for genetic analysis is presented. Information from a total of 122 dogs was gathered using questionnaires and owner interviews, resulting in analysis of 52 aggressive (5 aggressive dogs were excluded from the analysis) and 65 control dogs. Owners rated their dogs with 5-point frequency scales for unacceptable behavior toward humans (17 items), fear (20 items), barking (8 items), and aggression toward other dogs (4 items). The results show that serious, repeated growling is the most pronounced single behavior characterizing the aggressive ECS, and this seems to be the most important behavior causing owners to classify their dogs as aggressive. The other main behavior characteristic of the aggressive group was skin-penetrating bites. Snapping and “biting in general” were also frequently reported among these dogs. The objective of this study was to describe some behavioral characteristics of ECS showing owner-defined aggressive behavior, and behavioral differences between these dogs and a group of ECS with excellent behavior.