What are wolf-dogs? Formally known as wolf hybrids, now called wolf-dog hybrids when the dog was re-categorized as a subspecies of a wolf. Wolf-dogs are the result of the breeding between a wolf and a dog. There are estimates that wolf-dogs numbers in the United States reach over 500,000. Sadly, many of these animals end up in our shelter systems, rescue organizations, euthanized or abandoned. The highest number of cases of aggression between wolves, wolf-dogs and domestic dogs occur in wolf-dogs. The reason being that I believe, is some wolf-dogs have a confusion in their head between what their domestic instincts and wild instincts are telling them to do. It also depends on what domestic breed is bred to the wolf. For example, a combination between a German Shepherd (high prey drive) and a wolf- high predatory drive as well, could be a lethal combination. Not all wolf-dogs are aggressive however in my experience, the majority of these animals do not make good pets and many of them suffer as the result.