The story that data reveals is complicated, but somehow very human.
Until about 13,600 years ago, any wolf living in what is now Alaska would have subsisted on the usual wolf diet: rabbits, elk, and a host of other land animals. But about 13,600 years ago, nitrogen isotopes in the bones of ancient wolves began to indicate that something had changed. Some wolves still made their living exclusively from hunting game, but others turned to living almost entirely from fish. Because it's unlikely that Alaskan wolves suddenly started fly fishing, the sudden change likely indicates that some wolves started getting food from humans.
They're good dogs, Brent
The fact that we kept trying to befriend wolves is abundantly clear at a site called Hollembaek Hill, where archaeologists unearthed the 8,100-year-old remains of four canines. Their diet consisted (according to the nitrogen isotopes in their bones) mainly of salmon, so it is tempting to assume that these were domesticated dogs. But their DNA shows that all four – including a newborn puppy – are most closely related to modern wolves.
On the other hand, Hollembaek Hill's canines did not all resemble wild wolves. At least one of them had the large build of a modern wolf, but others were smaller, like early dogs. And some of their DNA suggests they may be at least part dog, but not actually related to modern dogs. Lanoë and his colleagues suggest that 8,000 years ago, people on Hollembaek Hill lived alongside a mix of domestic wolves (don't try this at home) and wolf-dog hybrids.
All modern dogs trace their origins to a single group of wolves (now extinct) that lived in Siberia about 23,000 years ago. But sometime between 11,300 and 12,800 years ago, the canines from Hollembaek Hill and another site in Alaska called Swan Point had dog DNA that appears to have nothing at all to do with modern dogs. That may indicate that the domestication of dogs was a process that happened several times in different places, creating different branches of a dog family tree, but only one stuck around in the long run.
In other words, long after humans “invented” dogs, it seems that humans kept repeating the process and doing the things that created dogs in the first place: letting the friendliest, least aggressive wild canids live near their villages and perhaps adopt and feed them.
