Dumping the Dog Domestication Dump Theory Once and For All

A wide-ranging interview with researchers Christoph Jung and Daniela Pörtl.

Posted Nov 11, 2018

"To understand dogs we have to understand humans. Dog’s evolution is very closely linked to human evolution and history. It is an archaeological and paleontological issue and particularly a unique psychological and neurobiological challenge still today. Further research should deal with psychology, neurosciences, epigenetics and further disciplines in a broad and close multidisciplinary way." (Christoph Jung and Daniela Pörtl)

A recent essay by Christoph Jung and Daniela Pörtl called "Scavenging Hypothesis: Lack of Evidence for Dog Domestication on the Waste Dump" and available online caught my eye because of it's interdisciplinary nature -- it covers ecological, psychological, and neurobiological aspects of the way in which humans and wolves -- and scope. The authors write: "It is likely that they met very often and knew each other very well. We have some hints, that ancient wolves and people treated each other with respect cooperatively. We have hints for an active cooperation from humans and dogs starting in the Upper Paleolithic period long before it would have even been possible scavenging human waste. We have hints for emotional bonds between ancient people and dogs. Emotional bonds would have been unlikely for an animal hanging around human settlements while scavenging carrion and feces, like the scavenging hypothesizes describe. Looking at recent dogs and humans we have evidence for strong unique similarities in the psychological and neurobiological structures eventually allowing interspecific bonding, communication and working. Interspecific cooperation decreased the level of the stress axis of both species in the Paleolithic period and even does so today, what improves our social and cognitive abilities. We propose that dog domestication could be understood as an active social process of both sides." Some of these ideas are consistent with dog expert and Psychology Today writer Mark Derr's theories about how dogs became dogs about which he has been writing for many years (please see his book How the Dog Became the Dog: From Wolves to Our Best Friends and a summary of it), and also ideas put forth by Ray Pierotti and Brandy Fogg in their book titled The First Domestication: How Wolves and Humans Coevolved (for an interview with these researchers please click here).

I wanted to know more about Christoph Jung and Daniela Pörtl's wide-ranging ideas, so I asked if they could answer a few questions. Gladly they agreed and our interview went as follows (references can be found in their essay).

Why did you and Daniela Pörtl write "Scavenging Hypothesis: Lack of evidence for Dog Domestication on the Waste Dump"? How does it follow up on other research interests?

"We are able to provide strong evidence that wolves and ice-age hunters would have been able to understand each other and to develop individualized interspecific bonding. Living in the same ecological niche and hunting the same prey they knew each other very well and met very often."

(Pörtl) I grew up together with dogs, sharing the experience that dogs can provide love and emotional attachment bonds as a secure base in unsecure family circumstances with missing love and protection, in short, I like to say "dogs can save our souls". Due to this very personal childhood experience, I have been interested in the secrets of human-dog bonding already during my medical studies intensifying this interest while working as a neurologist and psychiatrist. Thus, I was glad to meet Chris in 2012 starting to develop together the model of Active Social Domestication showing that the dog domestication process is essentially due to emotional bonds reducing stress and improving prosocial behavior. Interspecific emotional bonding between wolves/dogs and humans is not only an essential feature of dog domestication but still plays an important role in every dog-human bond and especially in dog-facilitated therapy which offers positive effects on a wide variety of mental disorders.
(Jung) We both grew up with dogs as our best friends. When I was a toddler, my boxer named Asso was my emotional base. He protected me, he gave me the comfort of a loving family, not my mom or father. When I was 14 I earned my own money by working in supermarkets, as a postman and a worker in factories. With that money, I bought scientific magazines and books about mammals, especially about dogs and cats. All my life I was interested to explore the mystery of dog-human-bonding. I had the luck to study biology and psychology in Bonn with Professor Reinhold Bergler who was one of the founders of human-animal-studies (e.g. Bergler, Man and Dog - The Psychology of a Relationship, 1986). In this time, the late 1970s, I developed our basic ideas about dogs and humans.
We find 2 opposite points of views on dogs. For me personally, dogs are important social partners, sometimes even more important than humans are. With the definition of dog’s nature as scavengers on human waste dumps, dogs cannot be partners at eye level anymore. The Coppinger's emphasize their view quite clearly comparing them to rats and pigeons (Coppinger 2016, Page 224). When we came in touch with the dog science scene, we started wondering why Coppinger's ideas received such broad support. But we believe in dogs as our best friends. And we know why. To make it quite clear we had to debunk the scavenging model.
It was a stroke of luck that Daniela and I met each other. Together we were able to push our insights into new directions. In 2013 we published our model of the "Active Social Domestication of Dog". Interestingly we were receiving most interest from human medicine not from the so-called dog scholars. In our model we picked up the ideas from Wolfgang Schleidt and Mike Shelter (1998, 2003, 2018), Mark Derr (2012), and others, mainly in 5 items specially concerning how it would have been possible to switch from competition to an unique interspecific cooperation:
1. We introduced psychological and neurobiological mechanisms. Humans, wolves, and dogs show astonishing similarities in their social behavior, their psychology and social communication. We are able to provide strong evidence that wolves and ice-age hunters would have been able to understand each other and to develop individualized interspecific bonding. Living in the same ecological niche and hunting the same prey they knew each other very well and met very often.
2. So, it is basically possible to become familiar and eventually to cooperate. Some packs and some clans will have noticed the benefits of cooperation e.g. while hunting, defending a carcass, guarding in the night. But we introduce still another instance: working together. From competition to cooperation to working together, the dog is the unique species working actively together with human, having the so called "will-to-please". Working together is the central point to become confident and to evolve a deep understanding for each other. I worked more than 10 years in big factories as a machinist and I learned what a strong bond the working together culture might create.
3. We introduced epigenetics in human-dog-evolution. Thus we are able to understand the fast evolution from wolf to dog and from proto-dog to a Chihuahua and a Great Dane, to an herder and a sledding specialist. Mutation and selection is necessary, but not sufficient, to explain the very rapid and frequent changes in the process of domestication. Epigenetic inheritance and the functional role of genes shaping genomic plasticity are suspected to be crucial in domestication processes. We proclaim changes of the stress-axis to be crucial for domestication in general and in particular for dog domestication. Epigenetic impact decreased chronic stress even in humans thus pushing the evolution of human mental skills as well during the Paleolithic period - Archeologists call it "Aurignacien".

4. Last but not least, we adopt a strong multi-disciplinary approach.

In your essay you write, "Looking at recent dogs and humans we have evidence for strong unique similarities in the psychological and neurobiological structures eventually allowing interspecific bonding, communication and working. Interspecific cooperation decreased the level of the stress axis of both species in the Paleolithic period and even does so today, what improves our social and cognitive abilities. We propose that dogs domestication could be understand as an active social process of both sides. Further investigations need a closely networked multidisciplinary approach." Can you please tell readers more about the broad multi-disciplinary approach you adopt using human evolution, archaeology, palaeogenetics, psychology and neurobiology and why it is so important? (I agree with you here!)

(Jung) The dog is a very complex organism who you cannot understand simply by some behavioral black box studies in a laboratory or by simply analyzing its DNA. You need both, but much more. First of all you have to understand human evolution and society. The unique phenomenon of dog is that this species has been living, evolving and socializing entirely in the middle of our human society. Dogs and humans were working together in many ancient professions. Thus you must have broad knowledge of human evolution, archeology, and history. The ecological niche of dogs is the ecology of humans, their working methods, their food, and their ways of life. We must know exactly how people lived in the Paleolithic period to get a basis to understand dog’s origin and evolution. And that's only one basis, a necessary but even not sufficient basis.

(Pörtl) During the last 150 years, most dogs turned from a role in human production to one in our psychological well-being. Caused by dogs' unique human like psychological similarities, healthy benefits due to human-dog bonding are described. Recent research suggests a decrease of cortisol and an increase of serotonin and oxytocin as reasonable for this healthy effects. But interspecific social bonding between humans and wolf dogs already started in the Paleolithic period and is considered to have induced dog domestication as well as increased human cognitive evolution during the Aurignacien (Upper Paleolithic). Explaining dog domestication we have to deal additionally with climate changes, environmental factors, and the megafauna of the Pleistocene altogether shaping the behavior of ancient wolves and humans. We have to assess archaeological remains, palaeogenetic data and the knowledge of mammalian evolution. To understand dog domestication as an active social process of both sides we have to deal with the similar social behavior of wolves and humans based on their (neuro)biology. All these aspects are bound together in a "web of complex relations". Due to this complexity, we need a broad interdisciplinary approach for explaining dog domestication processes. The so-called domestication syndrome in dogs and other domestic mammals is characterized by reduced fear and hypersociability toward humans. Thus we suspect a reduced activity of the stress axis as well as improved activity of cross regulated serotonin and oxytocin calming system and inhibitory control of prefrontal brain. That means we have to deal particularly with changes of neurobiological structures because social behavior is always closely linked to brain function which is again shaped by genetics, epigenetics and environmental factors including social behavior. Due to the evolutionary continuity of mammalian brains the limbic brain, the stress axis, and the mirror neuron system are evolutionary conserved in social mammals thus allowing pro-social contacts between humans and wolves already during the Paleolithic period. Achieving an evolutionary benefit by using cooperation strategies, environmental stress was reduced hence creating less stressed individuals now evolving increased pro-social behavior and improved learning capability and inhibitory control.

Which interdisciplinary new findings are important to explain dog domestication as an active social process of both sides?

(Pörtl) Stress is an important factor in shaping behavior and brain function often showing lasting effects. Reduced chronic stress levels improve cerebral structures which are important for social and cognitive learning. As has been shown in the Siberian farm fox experiment, during domestication process chronic cortisol levels decreased and cross regulated pro social neurotransmitters and neuropeptides like serotonin and oxytocin increased facilitating empathy and interspecific pro-social behavior. The neuropeptide oxytocin plays an important role in mammalian bonding, empathy, social memory, trust, and in-group behavior. For example, domestic dogs yawn while watching human yawns, and this is correlated with the closeness of a dog’s social attachment to the yawning person, thus demonstrating empathy (Romero, 2013). Nagasawa (2015) shows that gazing into each other’s eye mediated by oxytocin also exists between humans and their attached dogs indicating interspecific empathy.
The mirror neuron mechanism is involved in empathy when both individuals are equipped with the same neuronal representation of an emotion or an action. Due to their similar social behavior in the same ecological niche, similar learning experience of ancient humans and wolves should have created equal neuronal representations, coding the observed actions and emotions. Recent functional magnetic resonance imaging (fMRI) studies in humans and dogs confirm similar activation patterns in their brains. Human mothers have similar brain activation in limbic brain regions when viewing their own child and their dog (Stoeckel, 2014). And dogs sniffing their owner show increased caudate activation indicating positive reward feelings as an indicator for positive emotional attachment (Berns, 2014).
Genetic polymorphism can modulate the function of evolutionary conserved complex mammalian brain systems shaping social behavior in relationships like higher or lower proximity seeking (Kis, 2014; Li, 2015; Oliva, 2016). Gene expression changes in brains of domestic dogs compared to wild wolves are confirmed due to brain function and nutrition (Axelsson, 2013). Hypersociability, a core symptom of domestication, is also associated with structural gene changes in dogs (von Holdt, 2017). But no genetic evidence indicates that the changes seen in domesticated animals are the result of single mutations. It is suggested that the domestication syndrome results from mild neural crest cell deficit migration during embryonic development where migration defects are particularly important whereby the reasons are still not surely known (Wilkins, 2014).

What are the nine assumptions of the dump/scavenging hypothesis and why are they not supported by research?
(Jung) We provide 9 basic arguments and there is strong and broad evidence for each of them (for references look at our paper/download).
1. We have to look at the time range dog domestication started
The scavenging model envisages dogs coming up around 8,000 years ago (Coppinger, 2016, Page 220), when humans started the epoch of settled agriculture. But there is clear evidence of much older dogs, pushing their origin back into an epoch 25,000 to 40.000 years ago. Archeologists and paleontologists commonly accept that the first reliable dogs are at least 15.000 years old. And we have to imagine that remains clearly identified as dogs are the late fossilized result of a long domestication process before, not the beginning. So already, this argument pushes basic assumptions for Coppinger's scavenging model aside.
2. Paleolithic people did not produce food waste dumps
Further, Paleolithic people did not build any food waste dumps. They used all of their prey for eating, clothing, warming or as tools. We have no archaeological hints for Paleolithic slaughter or kitchen dumps and especially not for bones with traces from wolf bites. If hunters sometimes had produced food waste, they never would have stored it nearby their camp simply so they didn't attract predators like other wolves, or bears or hyenas (and today native peoples still do so). All archeological papers concerning this item support this view. Paleolithic food waste dumps near settlements are simply a bad tale.
3. And never enough
Other scholars, promoting the scavenging model, are pushing the timeline back to the period of hunters and gatherers. But even if nomadic hunters might have temporarily produced food dumps (we argued, it's a tale), it could never have been enough to feed a founder group of new wolves. Paleolithic hunter clans consisted of only 20 to 50 individuals. There was extremely low population density. Even if people lived in temporarily camps producing food waste, it would have been never nearly enough to feed a founder population of wolves. The fundamental assumption of the scavenging hypotheses in all variations is that the ecology of wolves, characterized by “Group-hunting of ungulates” should have been changed to a new ecology of dogs characterized by “Human refuse scavenging” (Marshall-Pescini et al., 2015, p.83). However, there is a flaw, Paleolithic human food dumps are not supported by archeology.
4. Adaptation to starch-rich diet started much later than scavenging hypothesis proclaims
Looking at this issue, we get more strong evidence against any scavenging hypothesis. This model proclaims “The dog is a shape that evolved to a new niche that was created when people switched from hunting and gathering to growing grain. The waste products of that activity created a food supply that supports village dogs”. (Coppinger, 2016, Page 43)  With the beginning of settled agriculture, dogs had been slowly and until today only partly adapted to starch-rich diet, starting 7,000 years before present. Dietary adaptation in dog even reflects the spread of prehistoric agriculture. Thus, Nordic dog breeds show very little adaptation to starch-rich food till today. On the other side, some recent wolf populations are more adapted to starch-rich food than Nordic dogs and even adapted to marine dietary niches like on British Columbian islands. Therefore, today's food habits cannot create any explanation for domestication much more than 10,000 years ago.
5. Why wolves and not foxes?
The scavenging hypothesis argues that it would have been only the wolf who occupied the (virtual) new ecological niche provided by human food waste. Thus dogs derived. But why have wolves and not hyenas, bears, badgers, jackals or foxes been domesticated? They all were living in that period in the proximity to Homo sapiens. Foxes like scavenging on waste dumps, much more than wolves do. Foxes can be tamed very well as demonstrated in the Siberian farm-fox experiments. They are smaller than wolves and, living near or inside the camps, they would have been no potential risk for death of clan members, especially toddlers. If scavenging and hanging around nearby humans would have been the crucial impact of domestication, foxes or jackals would have been much better candidates for a self-domestication process on the waste dump. But neither foxes nor jackals have ever been domesticated in any culture or any period. Scavenging hypothesizes cannot explain why only the wolf, a potentially dangerous competitor, should have been domesticated.
6. Evidence for pre-historic working dogs
We have evidence for dogs specialized in polar bear hunting and also special sled dog breeds (original breeds) working together with hunter-gatherers 9,000 years ago. On Zhokhov Island in northern Siberia, humans always lived in hunter groups. These dog people never had any permanent settlements nor agriculture, but they had sledding dogs. Since the beginning of the Neolithic period, we have growing evidence for dogs as specialized working partners for hunting, herding, sledding, guarding in many regions, even something like dog breeds. We know cave paintings and rock art from northern-Africa or the Arabian Peninsula showing man and dog hunting or herding together and even the first leashes had been plotted thousands of years before the advent of settled agriculture occurred in these regions. A dog, able to work together with humans, an already specialized dog, maybe something like an early dog breed, could not derive just from scavenging and hanging around on waste dumps. Promoters of the scavenging model argue that dog breeds would be a very young feature starting in the Victorian age, referring to pedigrees and breed-standards created by the Kennel Club. Therefore, you may argue that grain- or cabbage-types/breeds did not exist before modern industrial standardization of agriculture. Just as you may argue that village dogs would be the original dogs (Coppinger 2001, 2016, Lord 2013, Hekman 2018) simply because they are the majority of recent living dogs. So, you may argue that living in megacities and eating from industrial livestock farming would have been the origin of human culture.
7. Honor for a scavenger?
Archaeologists have found a lot of Paleolithic graves containing dogs or dogs and humans together all over the world, for example in Green County, Illinois, 8,500 years old, a human-dog grave in Israel 12,000 years old, in Germany, 14,200 years old, in South-America, in the Far- and Near East. It surely was hard work to scoop out a grave with stone tools. The corpses had been buried carefully, partly provided with food for a life after death. From a psychological point of view we can assess such burials as an honor. It seems very unlikely that so much respect had been shown for a scavenger just hanging around. The grave in Oberkassel contained two humans and in addition the remains of two dogs, an older one and a puppy. The pup died at an age of seven months. An analysis revealed that it likely had a serious case of distemper. Without special care, this young dog would have died very shortly after contracting it the first time. But it received intensive human care. Lead researcher Janssens explains (2018): “That would mean keeping it warm and clean and giving it food and water, even though, while it was sick, the dog would not have been of any practical use as a working animal. This, together with the fact that the dogs were buried with people who we may assume were their owners, suggests that there was a unique relationship of care between humans and dogs as long as 14,000 years ago.” Working and living together, not side by side, leads to interspecific emotional bonds, to reputation and honor. Would have people shown so much care just for a scavenger?
8. Cooperation or competition
Recent European and North American cultures produce an image of the human-wolf relationship as a hostile rivalry and the wolf is seen only as a competitor. In all regions of Europe, wolves have been strongly hunted for hundreds of years. Wolves have been exterminated in wide areas, from Europe over Asia up to North America, for a long time. To survive, gray wolves had to become very timid. Their recent behavior is the result of a strong selection favoring the shyest and least socialized individuals. Thus, recent wolves try hard to avoid any human contact. But not all wild wolves do so. The Arctic wolves on Ellesmere or Baffin Islands do not fear humans as much. Arctic wolves (Canis lupus arctos) have never been hunted in large scale. They are interested to contact humans. It is documented that humans lived with Arctic wolf packs over several months and were even allowed to look after the pups in the den when the pack was hunting. Those Arctic wolves accepted human individuals as a kind of pack members.
9. Wolf as a friend in Native cultures
Indigenous peoples used to describe wolves as brother, grandfather, relative, companion, teacher, and even creator. From hunters of Siberia to Native Americans wolves and dogs are treated with much respect, mostly as friends or companions. In the pre-Christian religions and mythologies, the wolf is described in a similar way and regularly as a divinity or a companion of a divinity. It is quite rarely that the wolf is mainly described as an aggressive animal or only as a competitor. But wolves are never described as scavengers nor hanging around human settlements (see Pierotti and Fogg, 2017).

What hypothesis do you favor?

We suspect that the cooperatively and highly social behavior of ancient wolves and humans is one main reason for evolving dogs. Wild wolves lived - and still live today - in competition with humans and this was the reason for meeting each other during a hunt or while scavenging at a carcass. On the other hand, due to their similar social match, humans and wolves were able to begin interspecific pro-social communication with one another, first in all likelihood in order to avoid risk of injury. Over time, this allowed wolves and humans to cooperate mutually during a hunt or while raising their offspring thus creating an evolutionary benefit for both of them. We suggest the hypothesis of  "Active Social Domestication" (ASD) (Pörtl/Jung,2017) which argues that the interspecific emotional attachment bonds of ancient wolves and humans caused the dog domestication process facilitating mutual social cooperation and cooperation on both species. In addition, we suspect ASD to be an epigenetic disclosure changing interactions of the HPA stress axis and calming systems in the brain.

Domestication is a relationship between humans and animals that leads to morphological and behavioral changes. Domestication syndrome occurs very rapidly and frequently cannot be explained only by selection for mutations. Thus, we suspect epigenetic down-regulation of the stress axis to be crucial in improving the cross-regulated serotonin and oxytocin calming systems and inhibitory control in the brain. Epigenetic modulation means that environmental factors and behavior regulate gene activity and gene expression via DNA (de)methylation in brains, thus genes can be switched on or off. And indeed, the results of the Siberian farm fox experiment show physiological changes in the limbic brain of tamed foxes such as down-regulation of HPA stress axis, decreased cortisol levels, and increased serotonin and serotoninhydroxylase levels (Trut, 2009) which can be explained by the epigenetic downregulation of the HPA stress axis due to increased interspecific prosocial care (Meaney, 2005). Linked to positive emotional bonds toward humans, tamed foxes show an affected DNA machinery in limbic brain structures (Herbeck, 2016). Human wolf interactions caused an evolutionary benefit reducing environmental stress for both of them, thus interspecific prosocial care could increase. Due to increased prosocial care, epigenetic input is known to enhance the glucocorticoid negative feedback loop, hence decreasing the stress activity again even in the offspring now showing less fear of novelty. These epigenetic modulations are programmed in childhood, but stay relatively stable during adulthood protecting a strong effect of chronic stress reduction improving again increased prosocial behaviour and cognitive inhibition from generation to generation. Decreased cortisol enhances dendritic growth facilitating higher synaptic plasticity. fMRI brain imaging in wild and domestic mammals show that amygdala volume is reduced and the medial prefrontal cortex volume is enlarged in domestic animals (Brusini,2018) and this is consistent with the ASD explaining reduced fear (amygdala) and increased prefrontal inhibition and learning capability (forebrain cortex) in dogs. Thus, individuals of matched wolf-human clans became less aggressive and less anxious towards each other, showing increased interspecific friendly in-group behavior, although defensive aggression against out-groups still remained. Decreased chronic stress also improves juvenilized behavior, social learning capabilities, and inhibitory control of the prefrontal cortex. Tame wolves were able to grow into domesticated social dogs capable of working together with humans in an active form of partnership. Compared to wolves, dogs possess a higher level of inhibitory control allowing them to hunt together with humans already during the Upper Paleolithic and made it the first big evolutionary benefit of human-dog partnerships. Later on, dogs helped humans by transporting materials, even tending their sheep and goats. Eventually wolf dogs integrated themselves into human social structures accepting humans as their preferred social binding partner thus, tame wolves became domestic dogs. Today, described epigenetic mechanisms still work in human-dog bonding, reducing stress and enhancing social and learning abilities thus improving mental and physical health. Archaeologists describe a sudden increase in human cultural evolution in the Aurignacian, the time window of dog domestication, which might also be due to the described epigenetic modulations improving human mental skills during the dog domestication process as well.
What kind of future research is needed to shed more light on the domestication of dogs?

(Jung) We need more research concerning the common evolution and history -- in the Paleolithic period, antiquity and even modern times. It has been suggested that dog breeds are a new phenomenon starting in the Victorian age but this is not so. For example, we have clear evidence for breeding hunting dogs to be much older. Kings and dukes had their own dog breeding farms to create the best dogs for each hunting discipline. It was highly intentional breeding based on breeding-standards and pedigrees. 2,400 years ago Xenophon wrote Kynegetikos, a book about hunting with dogs which can be understood as a list of breeding standards and instructions. I would like "Cynology" to be re-established as an independent academic discipline with a multi-disciplinary approach.

(Pörtl) Dog domestication and other domestication processes occur very rapidly and frequently and therefore cannot be explained only by selection for mutations. Besides some morphological changes, the domestication syndrome is first of all determined by behavioral changes such as reduced fear and aggression toward humans. Environmental factors shape behavior, but changed behavior means changes in brain function often even causing changes of brain morphology. Thus, in my view, it is necessary to intensify neurobiological research due to domestication processes including fMRI studies as well as looking for epigenetic methylation patterns in brain. Today we know that even single acute stress as well as chronic stress can alter gene function but also regulate the expression of retrotransposons in brain thus leading to structural gene changes which is suspected to have adaptive functions at the level of both evolution and the individual organism (Hunter, 2014).

What are some of your current projects?

(Jung) We are conducting further investigations into the domestication phenomenon in general and in particular the impact on humans. What does it mean in our evolution, today's life, our (self)awareness? We think that dog-human coevolution has much more effect on our species than commonly thought. Some organizations in the field of human-animal interaction are very interested to use our theoretical approach for a better understanding of the effects from animals and dogs on our well-being and to improve dog-based therapy and intervention. I personally am fighting for 20 years for dog breeding reform to protect dogs from cruelty and to ban puppy mills. Last not least we want to introduce, discuss and improve our ideas. Thus, we are looking for a publisher to present our ideas to the U.S. market. And, we have to do our daily jobs as psychologist and psychiatrist.
(Pörtl) Dog domestication is only one example for domestication processes. We suggest that the neurobiological changes causing domestication due to reduced chronic stress and improved prosocial care are important for all domestication processes. Today it is commonly accepted that the dog is the first domesticated animal, but maybe we, Homo sapiens, were the first ones, reducing our environmental stress due to making fire, building weapons, and living in larger social groups. This will be one major point of interest for our current projects -- studying the evolution of the human mind and assessing the dog domestication process due to its role for improving human mental skills during the Aurignacian. On the other hand, it will be a great chance to introduce ASD as the neurobiological basis for dog facilitated therapy, explaining not only that it works, but how it works.

Is there anything else you would like to tell readers?

(Jung and Pörtl) Georges de Cuvier, founding father of paleontology and modern zoology, noted,
"The dog is the most complete, the most singular and useful conquest ever made by man...The swiftness, the strength and the highly developed power of scent in the dog, have made it a powerful ally of man against the other animals; and perhaps these qualities in the dog were necessary to the establishment of society. " (Animal Kingdom, 1817 p.90) These words, written 200 years ago, are full of wisdom and really true. The human-dog friendship is a big gift. We have the opportunity to help our own well-being. But we have to care for dogs and to respect them as our partners and friends not as (so-called) scavengers hanging around human waste as their "natural ecological niche".
(Pörtl) Chris, you have said it very well. I can add not more than dog-human bonding is very important for our 21st century where you find increased lack of social bonding.

Thank you both for a fascinating and wide-ranging interview. I so enjoy your multidisciplinary approach and how you weave together all sorts of data that at first glance seem unrelated. I wish you the best of luck in all of your work, and I hope your ideas receive a broad global audience.

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