AS NOTED IN CHAPTER 1, IT IS LIKELY COMMON KNOWLEDGE BY NOW that the gray wolf, Canis lupus, is the direct ancestor of the domestic dog. This chapter covers the history of work that makes such a statement possible, including some of the useful lessons learned in reaching that point, but it is initially important to impart some basic background. Accordingly, the present objective is to set the stage by clarifying the phylogenetic position of dogs. Within the taxonomic class Mammalia, they are assigned to the order Carnivora, or primarily flesh-eating carnivores. This order contains a variety of animals, including the cat, hyena, bear, weasel, seal, mongoose, civet, and dog families (Wayne 1993a: 218). The dog family is Canidae, and the Canidae, to put matters simply, “is a morphologically diverse family of dog-like carnivores” (Wayne & O'Brien 1987: 339). Based especially on genetic data, Wayne (1993a: 219, 1993b: 18; Wayne & Ostrander 2007: 557–559) divides the canid species into three basic groups: the wolf-like canids, the South American canids, and the foxlike canids. Figure 2.1 illustrates the basic phylogenetic affinities of different canid species and indicates the approximate timing of the origin of different root stocks leading to a particular species.

As indicated in their Figure 2 (Wayne & Ostrander 2007: 559), the dog falls within the wolf-like canid grouping, with particular affinities to a certain wild wolf-like canid.