Origins of the Modern Dog
Our furry four legged-friends come in all different shapes and sizes. When looking at that couch potato or goofball chasing their tail, it may be hard to believe these guys once were mighty ancient wolves.
That’s right….modern dogs descend from ancient wolves. While the modern day grey wolf is the closest living relative to dogs, it is believed that the now extinct Pleistocene Wolf may be the true ancestor to man’s best friend.
Although similar, these ancient wolves were distinctly different from our modern grey wolves.
So, How Did Wolves Become Dogs?
The newest theory, and the most likely answer is that dogs are the product of self-domestication. The thought is that early humans and dog’s ancestors developed a mutually beneficial relationship to increase each other’s chances of survival. The early humans shared food scraps with the wolves, while the wolves offered protection to those humans.
There is way more to the story then these brief answers to where dogs came from. Be sure to read on as we will take a look at the two leading theories as to how dogs came to be our modern buddies.
The Two Theories of Domestication
While none of us were around, there are two main schools of thought as to how dogs were domesticated:
Forced Domestication
The first, and more traditional idea is forced domestication. This idea is pretty straight forward and leans on the idea that early humans somehow captured wolf pups, kept them as pets, and gradually domesticated them.
This is the more traditional and older theory. It does make sense as humans have a habit of trying to make anything a pet – including rocks. So it’s not completely ridiculous.
However, there are some issues with this theory. For one, humans were in the hunter/gatherer stage. We were more nomadic at this point and there wasn’t a lot of room to feed mouths that didn’t contribute or add value to the group.
Additionally, finding a random wolf pup here or there would not amount to mass domestication. Further this leads to the idea that early humans were actively capturing many wolf pups. This seems somewhat off when you consider domestication doesn’t happen overnight and these groups of humans would have been dragging around undomesticated wolf pups while trying to survive.
When you combine those issues with scientific finds within the last 100 years, the theory of self-domestication starts to seem a bit more realistic.
Self-domestication
The theory of self-domestication is a newer theory, but seems to have the most credibility from an anthropological and rational standpoint.
Self-domestication centers around the idea that dogs ancestors basically domesticated themselves by slowly building a relationship of trust with early humans. Dr Brian Hare, of the Duke University’s Canine Cognition Center, explains self domestication in further detail in a publication (linked here if interested) and also shoots a big hole in the theory of forced domestication:
“That the first domesticated animal was a large carnivore, who would have been a competitor for food—anyone who has spent time with wild wolves would see how unlikely it was that we somehow tamed them in a way that led to domestication,” – Dr. Brian Hare (Smithsonian Magazine)
Dr. Hare explains that self-domestication in dogs likely began as their ancestor came in contact with early humans. Early humans were nomadic, meaning they moved from site to site as they hunted and gathered food. Inevitably, the wolves would have discovered the abandoned campsites and scavenged food scraps left by the humans.
In terms of survival, these wolves were faced with the choice to risk hunting versus following these humans around and living off of their scraps. It’s believed that those wolves chose the easier path of following around these humans for food. This most likely evolved into a mutually beneficial relationship where these early humans provided a food source to these wolves in exchange for these wolves offering security from other predators or wild animals.
It’s suspected that wolves who were more “friendly” would take the risk of getting closer to the humans. Over time the humans began to realize the wolves were not a threat. As this situation progressed over time, the trait of being less aggressive and more friendly would have become a more valuable to the overall success of the pack. Basically, a friendly demeanor became the key to more food and better chances for survival.
This was the start of what would lead to the close working relationship and companionship between these two species.
Domestication Changes the Way Animals Look
So if dogs are descendants of wolves, why do they look so different? How did they become the goofy fluff balls we know today? Well that has to do with with what is referred to as “Domestication Syndrome”. Domestication Syndrome is the name for the physical changes that occur when an animal becomes domesticated. Among these changes are floppy ears, variations in coat colors, shortened snouts, curly tails, and even decreased brain size.
While I am a self proclaimed nerd, I realize not everyone is. So, I’m not going to take a deep dive into the nerdy scientific details, but I will link the article here shortly if you wish to travel that road. For now, I’m just going to give you the main points.
The Novosibirsk Study
Just outside the Institute of Cytology and Genetics in Novosibirsk, Siberia there is an ongoing study of “domestication syndrome” that was started in 1959 by Dmitri Belyaev and is continued today by his mentee Lyudmila Trut.
Belyaev understood that dogs came from wolves, but despite their similarities there were significant differences in physical characteristics and temperament. Belyaev understood that domesticated species shared a set of similar features – floppy ears, shorter/curly tails, spotted coats, decreased stress hormones, and even longer breeding seasons.
This set of traits is what would become known as “Domestication Syndrome”. Simply put it’s the genetic changes that result overtime as a species becomes more domesticated. For his research, Belyaev decided to use silver foxes since he had worked with that species in other capacities before.
Belyaev and his team began breeding the silver foxes, but with a very targeted approach. For each generation of fox bred, he and his team would select the top 10% of the most tame foxes for continued breeding. This was the sole qualifier for selecting which foxes to breed next. This was done to isolate any genetic changes to tameness alone.
The initial results are absolutely crazy:
- After just 6 generations, in 6 years, these once wild foxes produced offspring that licked the teams hands, wagged their tails when humans approached, and even whined when humans left.
- After 10 generations, the foxes began to develop floppy ears and curly tails.
- After 15 generations, their adrenal glands became smaller and serotonin levels increased – meaning happier – less stressed demeanors.
Throughout the study even more cool things happened:
- Physical changes such as spotted coats, softer/rounded facial features, and chunkier legs.
- Longer reproductive seasons
- The ability to follow human gaze. This is a special trait that dogs have, but fully wild foxes do not.
This study has provided awesome insight into how these genetic changes occur over time due to tameness. I am by no means a neuroscientist, but I can somewhat understand what goes on. Basically, the tamer the animal, the more repressed the neural crest cells are. Neural crest cells are a kind of stem cell that develop in the womb and contribute to the development of several things in animals.
A decreased amount of neural crest cells result in less fear, splotchy coloring, smaller skulls, smaller teeth, and rounded snouts. This also affects cartilage resulting in floppy ears and curled tails.
This is a pretty huge take away from this study. Furthermore, it lends a lot of credibility to the self domestication theory. This reinforces the theory that the wolves that were more tame or more willing to approach humans had a better chance of survival, which meant more successful breeding. This would ultimately lead to severe changes in the species, resulting in our pups of the present.
As promised, if you are interested in the deeper scientific parts of this stuff, click here for the article featured in Evolution: Education and Outreach (2018).
So, we know wolves transformed into dogs, but when – and where – in the world did this happen?
When and where were dogs domesticated?
In a very simple nutshell, scientists cannot agree on the exact timing or location.
However, genetic studies have pinpointed Southern China, Mongolia, and Europe. Additionally, evidence shows that domestication was at least 15,000 years ago, but could be as early as 40,000 years ago.
Neolithic European Domestication
According to a study (linked here) from evolutionary ecologist, Dr. Krishna R. Veeramah, of Stony Brook University suggests that after genome examination of two Neolithic German dog fossils (7,000 years old and 4,700 years old), it appears that the domestication of dogs came from one single domestication event.
“Contrary to the results of this previous analysis, we found that our ancient dogs from the same time period were very similar to modern European dogs, including the majority of dog breeds people keep as pets. This suggests that there was no mass Neolithic replacement that occurred on the continent and that there was likely only a single domestication event for the dogs observed in the fossil record from the Stone Age and that we also see and live with today.”
-Dr. Veeramah.
However, this may not be the full story as these were the dogs that originated in a domestication event in Europe during that time.
Several scientist disagree with Dr. Veeramah and believe the domestication event in Neolithic Europe was not the only domestication event.
East Asian and Western Eurasia Domestication
A study published in Science magazine, pointed to DNA evidence that seems to show that wolves were domesticated twice. According to the genetic research, a separate group of wolves were domesticated in Eastern Asia and Western Eurasia. This evidence is found in distinct genetic difference between the European and Western Eurasia/East Asian groups.
It is believed that as people migrated west, so did the Western Eurasian/East Asian dogs. According to proponents of this theory, these dogs appear to have outcompeted, and in large part replaced a good amount of the ancient breeds of Europe.
Conclusion
The scientific evidence is pretty clear. The modern dog, while a descendant of an extinct and ancient wolf, clearly looks very different from years of progressive domestication resulting in the characteristics of “Domestication Syndrome”.
Additionally, we know this domestication did not just happen in one location at a single point in time. After evaluating all the information we have, one theory just seems and feels more realistic. While humans are certainly known to do stupid things that threaten their existence, it’s hard to believe that humans of the hunter-gatherer period would have risked trying to capture wolf pups for selective breeding. It just seems impractical for the time.
It seems far more realistic that the ancient wolves and humans formed a mutually beneficial relationship that progressed over time. As mentioned earlier, the wolves that were more comfortable approaching the camps would be rewarded with scraps and leftovers. It also makes perfect sense that the humans would realize and utilize the wolves to keep other predators away.
The wolves that approached the camps would have better resources and thus more likely to be successful at surviving and reproducing. As each generation became more “tame”, it is only logical that at some point these wolves, like Belyaev’s foxes, would have become happy to see the humans and even become affectionate to them as time passed.
Thus the awesome partnership between humans and dogs began. While other animals can be great pets, and have a place in our heart, there is something unique and special about the bond, trust, and relationship between our two species. While they may not look like or act like ancient wolves, dogs are just as important to us today as they were to our ancestors long ago…smaller brains and all.