Searching for an answer we - Daniela Pörtl and Christoph Jung - have got involved in biology, neurology, psychology, archaeology and epigenetics and developed the model of active social domestication from the wolf to the dog. In our model we will try to explain why.
Our statements are:
- Genetic selection is a necessary prediction of but not a sufficient explanation for changes from the wolf to the dog.
- Domestication is essentially an epigenetic based process of modulation of CNS neurotransmitter activities.
- Dogs dispose of new qualities, which are:
- increased prefrontal inhibition / empathy concerning to humans (basic ToM) and
- increased learning ability regarding to human behavior
- Eventually dogs became multipurpose and active working and social partners to humans.
|Dogs are multipurpose and active working partners to humans for more than 10.000 years. (Photo: Christoph Jung)|
|A fragment of a large bone, probably from a mammoth, Pat Shipman reports, was placed in this dog's mouth shortly after death. This finding suggests the animal was according special mortuary treatment, perhaps acknowledging its role in mammoth hunting. The fossil comes from the site of Predmosti, in the Czech republic, and is about 27,000 years B.P. old. This object is one of three canid skulls from Predmosti that were identified as dogs based on analysis of their morphology. (Text: PennState Science Photo: Anthropos Museum, Brno, the Czech Republic, courtesy of Mietje Germonpre.) look at Petwatch June 2014|
Thus domestication process started.
Domestication means among others decreased flight distance and decreased sensory threshold chiefly concerning to humans, so we have to focus on limbic brain regions which play a key role in mood control. Sensitive to glucocorticoids and innerved by serotonergic projections the (HPA)stress axis and the serotonin system are closely cross-regulated under physiological conditions.
|Epigenetics: High-nurturing mothers raise high-nurturing offspring, and low-nurturing mothers raise low-nurturing offspring. This may look like a genetic pattern, but it's not. Whether a pup grows up to be anxious or relaxed depends on the mother that raises it - not the mother that gives birth to it. © 2014 University of Utah|
|(Photo: Christoph Jung)|
But a tame wolf is not yet a dog.
High cortisol levels hinder neural structures which are important for learning. But tame wolves were used to human presence, hence epigenetic decreased cortisol levels enabled them to learn better from humans. Due to similar social behaviour and similar mirrow neuron mechanism empathy and ToM could increase amomg both specimen. Thus, the tame wolf could grow into a domesticated social dog getting able to work together with humans in an active form of partnership.
Dogs are told to be man's best friends. But why?
Today social interaction between humans and dogs is still reducing the activity of HPA stress axis in both specimen as explained in the model of active social domestication. Reducing stress and invigorate therefore social and learning ability might be the reason of the benefit of dog facilitated therapy in medical and social treatment.
|(Photo: Christoph Jung)|
- Model of active social Domestication from the Wolf to the Dog (Poster auf der ISAZ 2014 Animals and Humans Together: Integration in Society), Booklet still only in German
by Daniela Pörtl and Christoph Jung