Dog from multiple grey wolf populations, with the dingo and New Guinea singing dog "breeds" having developed at a time when human populations were more isolated from each other. In the third edition of "Mammal Species of the World" published in 2005, the mammalogist listed under the wolf "Canis lupus" its wild subspecies, and proposed two additional subspecies: ""familiaris" Linneaus, 1758 [domestic dog]" and ""dingo" Meyer, 1793 [domestic dog]". Wozencraft included "hallstromi" - the New Guinea singing dog - as a taxonomic synonym for the dingo. Wozencraft referred to the mDNA study as one of the guides in forming his decision.
Origin of the domestic dog pairs. Today, the most widespread form of inter-species bonding occurs between humans and dogs. The concept of friendship has ancient origins but it may have been enhanced through the inter-species relationship to give a survival advantage. In 2003, a study compared the behavior and ethics of chimpanzees, wolves and humans. Cooperation among humans' closest genetic relative is limited to occasional hunting episodes or the persecution of a competitor for personal advantage, which had to be tempered if humans were to become domesticated. The closest approximation to human morality that can be found in nature is that of the gray wolf,