The Stone age (source Wikipedia/Wikimedia Commons)
This article, written by Pawsitively Terriers Founder Member John Howells, is posted in his memory with permission of his executors, Mr and Mrs Birch. It is an excellent article and well worth reading, keeping in mind that research in this field id ongoing.
1. INTRODUCTION.
If you look very carefully at the 19th Century vision of life in the Stone Age pictured above, you will find a small dog in the background. Most recent genetic research seems to indicate, though, that rather than being just a “ background” creature, the early dog paid a very significant part in human activity from the earliest times. In fact some scientists believe that the success and expansion of modern humans owes much to the domestic dog. DNA analysis, combined with fossil discovery is providing firmer evidence on the origins of dogs and when, where and how they were first domesticated by humans.
2. WHERE AND WHEN?
There has been and still is, to some extent, considerable scientific debate on the subject. Until 2009, it was thought that the domestication of wolves took place less than 17,000 years ago and was possibly associated with the herding and guarding needs of the first farmers. It has also been widely believed that dogs are descended from the same family branch as the modern grey wolf. There has also been debate, (not yet fully resolved) regarding where this first
domestication happened , with, perhaps, the Middle East and Siberia/East Asia being the leading candidates .
However, the most recent genetic research undertaken by the University of Los Angeles, California suggests that dogs were first domesticated in Europe between 18,000 – 30,000 years ago and that they are descended from a sub-species of ancient European wolf, now extinct. In fact, genetic research may also indicate that there was an evolutionary split between dogs and wolves as long as 100,000 years ago, with early “dogs” having a shorter broader skull than wolves and smaller brain size. However the earliest fossils found so far date to 31,700 years ago (Europe) and 33,000 years ago (Siberia).
A study of foxes in Russia has shown that selective breeding for reduced aggression can bring about physical changes in successive generations including differences in size, conformation and coat colour. If fossil evidence has been found indicating a physical difference between dogs and wolves over 30,000 years ago, then this would suggest that the process began earlier than that. However, it should also be remembered that physical changes in dog populations could have happened very quickly in evolutionary terms – possibly within the space of a single human generation . It is very easy to find evidence of this if you look at changes in the physical characteristics of certain dog breeds over the last 100 years or so. I suppose an interesting question is whether evolutionary changes in a wolf species contributed to its domestication or whether this change happened as result of domestication? Possibly both may be true to some extent. The further you go back in time, the more difficult it is to discover fossil evidence, but we know from research into human origins that one or two rare discoveries can completely change our understanding of early history. I don’t pretend to understand the genetics, but why does there seem to be a divergence between dogs and wolves around 100,000 years ago I wonder? Could it have been related to human contact? No doubt the scientists will explain sometime soon.
33,000 year-old dog skull, Siberia (Wikipedia/Wikimedia Commons)
Note: The small hole made in the top of the skull may be a deliberate human act to release the
“Spirit” of the dog, a practice sometimes applied to fellow humans.
“Spirit” of the dog, a practice sometimes applied to fellow humans.
3. WHY and HOW ?
The main theory of how humans first domesticated wolves seems to be that basically, they raised very young wolf cubs. I don’t know a lot about raising and domesticating wild animals, but I get the impression that it is far from an easy task ( with wolves in particular ) even in the modern world.
It does make you wonder how they would obtain and raise cubs in sufficient quantity to allow them to breed from the adults and perhaps more significantly – why would they bother? I thought the concept of early farmers domesticating wolves was a bit puzzling. If you had livestock, why would you want a predator around?
Recent research seems to indicate than an early type of wolf was domesticated first by hunter–gatherers. It still seems fairly unlikely to me that this was done by rearing young cubs. How would chance rearing of cubs result in subsequent generations relatively low in levels of aggression? The study of foxes in Russia I referred to earlier showed that young foxes with higher levels of inherent aggression did not become tame, even when raised by people. On the other hand, raising fox cubs with lower levels of inherent aggression did result in “tameness” in subsequent generations and interestingly, was also accompanied quite quickly by physical changes so these foxes became more “ dog- like” in appearance.
It seems to me more likely that the first wolf-dogs were pre-disposed to lower levels of fear and aggression, partly self-selected themselves for domestication. A theory set out in “Science Daily”, (November 2013) by Robert Wayne a professor of ecology and evolutionary biology at UCLA
suggests that, as in the modern world, the early wolf/dog was attracted to the rubbish around human settlements (and I would guess, possibly the vermin associated with these). The natural instinct of the wolf is to flee from humans. The theory suggests that those wolves with the lowest inclination to flee (described as flight distance), would have had a better chance of surviving and breeding successfully than others of their kind, particularly during times of
hardship.
It also seems logical that their offspring would have inherited lower levels of fear of humans and might have become even more “accepting”, if thrown the odd scrap now and then. The theory also suggests that this transition from “wolf” to “ dog” could have taken place in as short a period as a single human generation. These early dog-wolves would have given up their usual territorial hunting patterns and instead migrated as the humans did, following prey.
The question remains – why did early man bother? In the modern world “garbage dump dogs” are not regarded favourably by all and some cultures still regard dogs as unclean and disease-carriers. My guess is that possibly these early dogs might have kept vermin down around human settlements, they may have deterred or warned of other predators ( or people ), or indeed they may have been regarded with some respect as “spiritual” beings. A tribe in present-day New Guinea still believe their hunting dogs find prey by the use of supernatural powers. How else could
dogs be so effective at hunting the unseen?
Of course before dogs could be used for hunting or any other purpose, they would first need to be domesticated. Did humans actually plan to domesticate dogs to hunt with? I think this is less likely than dogs becoming domesticated and integrated in human communities first through regular association , then very quickly their usefulness in hunting and guarding would have become apparent. Of course some dogs would have had better skills than others and these dogs and their off-spring would have been more valued.
Based on fossil discoveries, it is estimated that these early wolf-dogs were about the size of a Modern German Shepherd and it has also been suggested that they might have been used to transport burdens as some North American native peoples have done even in fairly recent times and still do with dog sleds in some parts of the world. Dogs therefore may have helped not only with providing a food supply, but also transporting it, as well as enabling humans to move
from place-to-place more easily.
Native Americans with dog Travois (foreground)
(Wikipedia/Wikimedia Commons)
Interestingly, it is suggested by some scientists that the ability of modern humans to domesticate dogs may have been influenced by their own development and may be partly related to improved human vocalisation and Pat Shipman in an article in “ American Scientist” (Do the eyes have it? – May/June 2012 ), also suggest that it may be in part because homo sapiens have “ white eyes” (a genetic mutation), allowing dogs to follow our gaze as part of the communication process. The dog’s ability to follow the human gaze has been proven scientifically.