Where do dogs come from?
Have you ever wondered how your sweet snuggle muffin couch potato could possibly be related to wolves? Well, truth be told, dogs do not descend from modern wolves, although they do share a common canid ancestor.
Dogs were the first animals that were domesticated by humans. While we know this to be a fact, there is little else that we know with absolute certainty about the domestication of dogs. Domestication is the process of influencing the reproduction of an organism such that genetic changes occur. The result is that the animals begin to serve a purpose for a population of humans, and often includes the emerging dependence of a species on humans for survival.
Domesticated dogs (Canis familiaris) share 98.8% of their DNA with modern wolves (Canis lupus). However, while science has long understood a close connection between modern gray wolves and domesticated dogs, genomic studies now make it clear that modern dogs and modern wolves are both derived from a common ancestor, the now extinct Eastern Eurasian wolf (Canis lupus lupus). It is very hard to pinpoint the exact time and place when Eastern Eurasian wolves began to genetically shift toward something recognizable as a dog. The only point of comparison that could lend us some specificity is the morphology (appearance) of bones found at archaeological sites. However, while these canids may have appeared different to ancient people in contrast to one another, their bones remain very similar for some time. It is probable however, that dogs began to evolve into what we now understand to be dogs as early as ~33,000 years ago (or more). What changes we can see slowly occur in bones found at ancient sites show that genetic shifts resulted in a smaller version of the wolf, with relatively shorter snouts. In addition, isotope analyses of the calcium and nitrogen in the bones and teeth of these specimens also indicate that the diets of these transitional canids were beginning to vary from that of their ancestral Eastern Eurasian wolves. There is also growing evidence that these genetic shifts led to behavioral changes associated with sociability, with domesticated dogs becoming juvenile in looks and behavior (neotony), and therefore more accepting of group members of other species, such as humans and other animals associated with humans.
While the domestication of the dog would have ultimately involved both the taming and rearing of an animal population(s), the details of this process are the subject of much interest and research among zooarchaelogists and zoogeneticists, with many contending theories regarding the time(s) and place(s) where this may have occurred. While it is clear that dogs developed in Eurasia, exactly where is still out for debate. There is evidence for the early development of animals that we might recognize as dogs across Asia, Europe, and the Middle East, most zooarchaeologists believe that all roads lead back to Siberia where by ~23,000 years ago, canids distinct from wolves began to appear. However, science has not yet shown whether these sites indicate the same domestication event, where one population of dogs traveled alongside human populations, or if dogs were domesticated separately, and at different times. What we do know at the very least, based on genomic evidence, is that dogs were domesticated during the coldest part (the Last Glacial Maximum) of the last Ice Age, when glaciers covered 8% of the earth’s surface and completely isolated whole populations of people and animals from one another. There is no doubt that when these glaciers began to retreat, and people followed game to warmer climes, these early dogs did indeed travel with them, and ultimately spread alongside humans throughout the world.
No one knows exactly why or how these canids were domesticated, and whether this move was intentional or incidental. We do know that, unlike other domesticates, the evolution of the dog was not the result of human movement toward an agrarian lifestyle. The humans who lived alongside these canids were hunter-gatherers, well before the beginning of agriculture. This fact opens up some theories regarding why dogs became systematically incorporated into peoples’ lives and integrated into their lifeways during this time, and have been ever since. The leading theories are shaped around their potential for guarding, hunting, and/or companionship. One widely accepted theory is that the more sociable, less timid wolves approached human campfires for warmth and food scraps. Humans found this behavior useful, in that the wolves protected these safe sources of food and warmth from other predators. Over time, the theory goes, these individuals became so tied to the lives of the humans with whom they lived alongside that their relationship grew symbiotic, providing one another with support during hunts, protecting one another, and providing companionship. There is also a popular theory that members of a human band took in wolf pups (either orphaned or stolen from their parents) and raised them, thus beginning the domestication of wolves. Both of these scenarios could be true, as both dogs and dog lovers are variable and capable of such relationships. The truth is probably more complicated.
However, let’s be clear, dogs are not wolves anymore than humans are bonobos or chimpanzees, animals with whom we share 98.7% of our DNA. Dogs have been evolving away from their common ancestor with the modern wolf for at least 15,000 years, if not longer. Probably way longer. The development of modern dogs has occurred over thousands of years in very close concert with the humans with whom they shared the landscape, resources, and lifeways. Modern humans and modern dogs have evolved together, from the ravages of the last Ice Age to the searing heat of this age, in order to help one another survive, and as companions in the various routes our lives have taken. Both dogs and wolves are amazing creatures, each in their own, distinct way. But dogs belong to us, and us to them. We have so much to appreciate in our dear life companions, and a huge responsibility to continue stewarding them through the changing landscape in return.