Wolves as pets and working animals
Generally speaking, on the basis of their experience, tame wolves are strictly "one-man dogs". They may be confiding and playful with the man who raised them, or even with his whole family, if fed and cared for by them, but they are suspicious and timid in the presence of strangers. They invariably retain certain reactions of wolf nature, as for instance, an incorrigible desire to kill chickens or other small livestock whenever opportunity arises.
Wolfdog
The physical characteristics of an animal created by breeding a wolf to a dog are not predictable, similar to that of mixed-breed dogs. Genetic research shows that wolf and dog populations initially diverged approximately 14,000 years ago and have interbred only occasionally since, accounting for the dissimilarity between dogs and wolves in behavior and appearance. In many cases the resulting adult wolfdog may be larger than either of its parents due to the genetic phenomenon of heterosis (commonly known as "hybrid vigor"). Breeding experiments in Germany with Poodles and wolves, and later on with the resulting wolfdogs showed unrestricted fertility, mating via free choice and no significant problems of communication (even after a few generations). The offspring of poodles with either coyotes and jackals however all showed a decrease in fertility, significant communication problems, and an increase of genetic diseases after three generations of interbreeding between the hybrids. The researchers therefore concluded that domestic dogs and wolves are the same species.