that aggression is displayed more in certain breeds, which indicates the influence of genetic background on aggression in dogs. According to Roll and Unshelm, German Shepherd dogs and Bull Terriers are more likely to display violent behavior to others. Voith and Borchelt found that higher incidences of aggressive behavior were displayed in purebred dogs when compared with mixed breed dogs. Often, aggression in adult dogs is usually a result of little to no contact in early life. In other words, as a result of missed early socialization, a dog will not know how to interact with others, how to follow rules or how to adapt to new environments. Aggressive behavior is more prominent in intact males when compared with neutered males and in sterilized females than intact females. According to Hoerlein, the removal of a male's testicles has significant impact on aggressive and dominant males. Neoplasia of the central nervous system, infectious diseases, developmental and metabolic disorders may impact aggression in dogs. Many of these illnesses can cause aggressive and violent behavior, especially when located in the frontal cortex, the hypothalamus, the thalamus, the amygdaloid body, the medial mammillary, the nucleus, the habenular nuclei, the hippocampus and the caudate nucleus. Research Gonadectomy Gonadectomy is used to treat aggressive behavior of dogs. Farhoody and colleagues carried out a study to determine the impact of gonadectomy on the aggressive behavior of dogs using the Canine Behavioral Assessment Research Questionnaire (C-BARQ). According to the data collected, gonadectomized dogs between the ages of 7 and 12 months were more likely to be aggressive to strangers. Furthermore, gonadectomized dogs of all ages do not display violent behavior to familiar people or strangers. The data does not show that gonadectomy prevent or treat aggressive behavior of dogs. Based on McMillan and colleagues’ research, aggressive behavior was prominent in dogs obtained from pet stores. Guy and colleagues found that environmental factors directly contributed to aggression in dogs. For instance, a dog that lives in a home with an adolescent or has a skin disorder is more likely to exhibit aggressive behavior to familiar people and strangers. Roll and Unshelm believed that the reason for buying or adopting a dog was a significant factor that correlated with aggression. They also argued that the relationship between the owner and dog determined whether or not the dog would exhibit aggressive behavior. For instance, the owner's attitude towards training, or physical