In celebration of National Dog Day, come with me as we go back in time to where it all began. No, not as recent as 7 years ago for the start of our blog, Living with a Golden. Even farther back than 1868, when the first Golden Retriever was bred in Scotland. No, I’m taking you all the way back, approximately 20,000 to 40,000 years ago to when scientists theorize that dogs diverged from wolves and became domesticated. Today we’re exploring the evolution of dogs!
Dogs didn’t have social media accounts back then, so there’s no pinpointing exactly when or even how dogs started to hang out with humans. However, DNA and fossil evidence show that dogs are a direct descendant of wolves. Yet even that is complicated. At first scientists thought we evolved from a single wolf sometime during the Stone Age in Asia. Yet after analyzing the mitochondrial DNA sequences from the remains of European dogs thousands of years old, including one who was 4,800 years old and found buried in Ireland, scientists began to rethink our origins. Some believe that dogs were domesticated in Asia, at least 14,000 years ago, and then split 14,000 to 6,400 years ago into East Asian and Western Eurasian dogs. Leading some to theorize that dogs were domesticated twice, but the European branch of our family tree faded out at some point, leaving little genetic influence in modern dogs today. Yet it is important to note here that not all scientists agree with these findings, and attempts to replicate the research has been complicated.
Speaking of complicated, although there are plenty of movies and books speculating that this human and canine bond started when someone long ago got smitten with a wolf puppy and decided to keep it, or perhaps took pity on an injured wolf, like all relationships, there is probably a lot more to the story. Let’s face it, wolves and humans were both carnivores who hunted for the same food. So perhaps the relationship evolved as a means to help each other. There are some researchers who speculate that because dogs are the only animal known to have been domesticated by hunter-gatherers, it was done to assist them with hunting.
While other scientists theorize it was a case of “survival of the friendliest,” in which wolves figured out if they acted friendly towards humans, they could benefit from these hunter-gatherers. So perhaps it wasn’t the humans’ idea at all? Maybe wolves were behind this friendship tens of thousands of years in the making?
Others theorize it happened quite by accident. Wolves were no doubt following the trail of the hunter-gatherers to feast on the scraps they left behind. Docile wolves may have attracted their attention and received extra food scraps from the humans, leading them to have better nutrition for survival. Thus enabling them to pass down their genes, and over time accidentally breeding friendlier wolves.
We probably will never know the exact reasoning behind origins of this bond. What we do know though is the longer these they hung out with humans, they began losing their distinct wolf traits and started developing a mutt-like appearance with curly tails, floppy ears, and other physical changes. As Dr. Brian Hare, director of the Duke University Canine Cognition Center explained, this process is a form of self-domestication, in which the friendliest animals gain the advantage, and somehow drives physical changes which can appear in later generations.
What we also know is the archaeological record and genetic analysis show that the remains of the Bonn-Oberkassel dog buried beside humans 14,200 years ago is the first undisputed dog. Analysis of the bones and DNA revealed it was not a local wolf, and had undergone some form of domestication. The fact that archeological evidence shows that it was purposefully buried with two humans, further shows there was a bond between them. However, even more interesting is a pathology study of the dog’s remains suggested it died from canine distemper sometime between 19 and 23 weeks of age. This dog, or should we say puppy, was too young to serve a utilitarian purpose to these humans. Leading Luc Janssens and associates in “A new look at an old dog : Bonn-Oberkassel reconsidered,” in the Journal of Archeological Science (2018), to theorize that there must have been an emotional or symbolic tie between these humans and this dog.
In summary, all modern dogs are the descendants of wolves. However, despite being domesticated wolves, over tens of thousands of years not only did our behavior change, but so did our appearance. Thus leading dogs to be classified as Canis familiaris, and not Canis lupus for wolves. Exactly what made us so endearing to humans, we may never know. Also as for how did we evolve into so many distinct breeds? Well that’s a story for another day. However, we can all agree with Brian Hare when he stated, ‘The domestication of dogs was one of the most extraordinary events in human history.” Thus why today we are celebrating National Dog Day!
