Origin of the domestic dog

The origin of the domestic dog is not clear. The domestic dog is a member of genus Canis (canines) that forms part of the wolf-like canids, and is the most widely abundant carnivore. The closest living relative of the dog is the gray wolf and there is no evidence of any other canine contributing to its genetic lineage. The dog and the extant gray wolf form two sister clades, with modern wolves not closely related to the wolves that were first domesticated. The archaeological record shows the first undisputed dog remains buried beside humans 14,700 years ago, with disputed remains occurring 36,000 years ago. These dates imply that the earliest dogs arose in the time of human hunter-gatherers and not agriculturists. The dog was the first domesticated species.

Where the genetic divergence of dog and wolf took place remains controversial, with the most plausible proposals spanning Western Europe, Central Asia, and East Asia. This has been made more complicated by the most recent proposal that fits the available evidence, which is that an initial wolf population split into East and West Eurasian groups; these, before going extinct, were domesticated independently into two distinct dog populations between 14,000–6,400 years ago. The Western Eurasian dog population was partially and gradually replaced by East Asian dogs introduced by humans at least 6,400 years ago.

Six million years ago at the close of the Miocene era, the earth's climate was gradually cooling and this would lead to the glaciations of the Pliocene and the (the Ice Age). In many areas the forests and savannahs were being replaced with steppe or grasslands and only those creatures that could adapt would survive. On opposite sides of the planet, two very different lineages would adapt to these changes and their evolution would produce two species that would become the most widely distributed of mammals. In southern North America, small woodland foxes were growing bigger and becoming more adapted to running, and by the late Miocene the first of the genus Canis had arisen, the ancestors of coyotes, wolves and the domestic dog. In eastern Africa, a split was occurring among the large primates. Some would remain in the trees, while others would move out of the trees, learn to walk upright, develop enlarged brains, and learn to avoid predators while becoming a predator themselves in the more open country. The two lineages would ultimately meet on the Eurasian continent. "They were individual animals and people involved, from our perspective, in a biological and cultural process that involved linking not only their lives but the evolutionary fate of their heirs in ways, we must assume, they could never have imagined."

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