A very important thing to consider about the relationship between wolves and dogs is that domestic dogs from a certain region share many physical similarities to wolves from that same location. These kinds of important similar traits have been seen far too often in the whole world for it to be caused by coincidence. In 1829 Sir John Richardson recorded that “the resemblance between the North American wolves and the domestic dog of the Indians is so great that the size and strength of the wolf seems to be the only difference”.
Some people have suggested that the fact that dogs bark while wild wolves only howl is proof that they are not related. This, however, is quite absurd since it is well recorded that any wild member of the canine family raised by a domestic mother will learn how to bark. It goes both ways as dogs allowed to run wild will forget how to bark. What people are witnessing is learned behavior, something common to many mammals. It is not a sign that the two species are not related.
The influence of the behavior of barking can’t, then, be regarded as an argument in deciding the issue concerning the origin of the dog. This opposition consequently fails, leaving us with the sensible choice of agreeing with Darwin, whose final hypothesis was that “it is highly probable that the domestic dogs of the world have descended from two good species of wolf (C. lupus and C. latrans), and from two or three other doubtful species of wolves namely, the European, Indian, and North African forms; from at least one or two South American canine species; from several races or species of jackal; and perhaps from one or more extinct species”; and that the blood of these, in some cases mixed together, flows in the veins of our domestic breeds.