A wolf dog (also called a wolf–dog hybrid or wolf hybrid) is a canid hybrid resulting from the hybridization of a domestic dog (Canis lupus familiaris) to one of four other Canis sub-species, the gray (Canis lupus), eastern timber (Canis lycaon), red (Canis rufus), and Ethiopian wolves (Canis simensis).
One of the issues that many researchers and wolfdog communities are faced with is identifying wolfdogs from pure dogs and any of the wolf species mixed into the hybrid.
The most common method used by various wolfdog communities is phenotyping, a method that involves observing the animal’s physical features. This method is often favoured for many in determining the degree of wolf and northern spitz-type dog that is in a hybrid. However, a lot of criticisms have been made by opponents within some communities who tend to point out that phenotyping cannot always determine the wolf-contents accurately.
Another challenge involves determining exactly the domestic breeds and wolf subspecies involved in the admixture due to the fact that dogs are known to come in various breeds while gray wolves in turn come in various subspecies with many different regional ecotypes hence have different physical features depending on the subspecies used in the breeding.
Although wolves are often mixed with spitz types such as Siberian Huskies, Alaskan Malamutes, and German Shepherds, hybrids between wolves to non-Spitz type dogs such as Poodles, Pitbulls, and Great Pyrenees also exist, the latter hybrids often having less lupine features.
Wolf-dogs are generally said to be naturally healthy animals, and are affected by fewer inherited diseases than most breeds of dog. Wolfdogs are usually healthier than either parent due to heterosis. Some of the established breeds of wolfdog that exist today were bred specifically to improve the health and vigor of working dogs.