In Dog We Trust – The Case For Man’s Best Friend

According to a recent survey about 36% of households in the USA have at least one dog. According to the Pet Food Institute this totals to around 57.6 million dogs, meaning there are nearly 3 times the amount of dogs in America as there are humans in Australia. Americans spend around $5.6 billion on food for their dogs and the American Veterinary Medical Association estimates around $7 billion dollars are spent annually on keeping dogs healthy. Why and how are humans so connected to an entirely separate and distantly related species like Canis familiaris? What makes dogs stand out from other domesticated animals and what can the study of human-canine co-habitation tell us about our own evolutionary history?

Let’s start with a very brief look at the ancestry of both dogs and humans. The canine group has its origins in North America and were originally small forest dwelling carnivores around the size of a fox. When open herd grazing ungulates like horse and antelope began to dominate the vast plains of North America the ancient canines radiated out from the forest onto the open ground. This created a canine ancestor that began evolving into a swift pack hunter in order to tackle the ungulate herds. It is thought that some of these ancestors migrated over the Bering straight into Asia, Europe and Africa around 10 million years ago. Over the next few million years these canids formed into the wolves, jackals, coyotes and painted dogs (not actually ‘dogs’) that we are familiar with today. The grey wolf (Canis lupus), the species from which domestic dogs arose evolved at the end of the Late Pleistocene around 300,000 years ago.

Meanwhile in Africa the ancestors of humans had been evolving steadily. The earliest member of the homo genus is currently identified as Homo habilis who lived from around 2.4-1.4 million years ago. Homo habilis was already using stone tools though it’s leg structure was more suited to tree dwelling than plains walking. After (and alongside) habilis arose Homo ergaster, who later gave rise to Homo erectus and Homo antecessor. Erectus and Antecessor were the first human ancestors to move far out of Africa and into Asia and Europe, both around 1.2 million years ago. Then from Antecessor came Rhodesiensis which finally evolved into Homo sapiens and Homo neanderthalensis. Homo sapiens have lived from around 250,000 years ago till present while poor old neanderthalensis disappeared around 30,000 years ago. So while canid ancestors beat us into Europe and Asia by a good margin the grey wolf from which dogs evolved arose at around the same time as modern humans.

The exact circumstances surrounding the first co-habitations of wolf and man are not known but evidence suggests the earliest interactions took place more than 100,000 years ago. Even before this time it is thought that humans may have been observing and learning from the wolves about how to hunt large ungulates on the tundra. What is known is that by 30,000 years ago dogs had split from wolves and were living alongside humans. The earliest clearly identified dog skeleton was found in Belgium and dates to 31,000 years ago. The March 2010 edition of the Journal Nature published a study that looked at tracing the geographic origins of the domestic dog using genetic markers. The genetic evidence shows that the domestic dog originated in the Middle-East, rather than East Asia as previously thought. It is logical to assume therefore that if the oldest dog remains we have are from Western Europe but dogs evolved in the Mid-East then the split must have taken placed many thousands of years before our oldest skeleton.


Wolfgang M. Schleidt/Michael D. Shalter, p.59 (2003)

But how exactly did we domesticate wild wolves in the first place? Unfortunately the exact circumstances will likely never be known, the great tragedy of all historical sciences. It is thought though that initially wolves began hanging around human campsites, picking off refuse and scraps of food. This would have created a selective pressure where those wolves who were less frightened and spent more time alongside humans would be favoured. This evolutionary pressure would have resulted in a combination of increased fitness in some wolves through extra nutrition and a mixing of the genes of those wolves who remained in the locale of humans over time. In no time at all geologically speaking, (perhaps 5,000 years) wolves were fully integrating into the societies of Paleolithic man in Asia and Europe.

What occurred at this important moment in human history is an event perhaps unparalleled in todays natural world. Man and dog became linked in a far more meaningful way than other examples of symbiosis or co-evolution. We gained in dogs a valuable hunting partner, effective guardians, a pest controller and later a shepherd. We also gained a close emotional companion and the social worlds of humans and dogs enveloped each other in a near seamless way, humans became part of their packs and dogs became part of our tribe. Evidence for the emotional bond between human and dog is informative and at times quite touching.

In both Eurasia and North America, archaeologists have found 10-15,000 year old dogs that have been buried beneath the floors of huts or tent-camps, curled in sleeping postures, and covered with the red ochre that people of the time used in human burials. In some cases the dogs are interred directly with humans, as at one Middle-Eastern site where a puppy was found curled in the arms of a buried human. Think about, for more than 20,000 years before agriculture began, before the first written language, before the earliest philosophers or world monuments, before the first organized religion or civilization nearly every pocket of mankind had formed a psychological, emotional and practical bond with dogs that lasts until today.

Many people today fail to understand just how in tune humans and dogs are with each other, without the need of any real behavioural learning. Anthropologist Brian Hare of the Max Planck Institute for Evolutionary Anthropology in Germany has reported that domesticated dogs are better at reading human communication signals, such as glances or pointing, than chimpanzees, which have long been thought to be closer to humans than any other primate. We are also acoustically in-tune with dogs, a study of dogs owners reports than on average each dog understands 30 different human utterances, 21 percent of which were synonyms. Understood utterances range in purpose over the following: Disallowance, Posture, Invitation, Referring to object or person, Unique, Information giving, Permission and Question. Owners believed that dogs executed 31 % of commands “every time”, 53 % “in contextually adequate situations”, and 16% only “occasionally”. Age of the owners or dogs, breed of dogs, and the educational status of owners did not strongly affect the utterance structure. These findings are also supported neurologically, with evidence showing that similar brain genes have changed in the same ways in humans and dogs since our co-mingling. With these sorts of findings it is important to keep in mind that this evidence shows that not only have dogs evolved to be more in tune with us, but we have evolved to be more in tune with them.

A hypothesis which is unfortunately hard to test but is fascinating and slowly gaining ground is that a great deal of what we consider very ‘human’ may in fact be very ‘wolf’ instead. When we see a dog demonstrating a novel or familiar behaviour we often marvel at how similar to humans it seems, but it may well be that they were doing it first and we copied them. There is no closer analog in nature to humanities familial and ethical system than in wolves. In the absence of our direct ancestors we often turn to our cousins the chimpanzees, but what we see there is a frightening reflection of our most egotistical side. The pioneering work of primatologist Jane Goodall gave us a fascinating insight into the sociality of chimpanzees. Unlike humans and wolves their social structure is highly individualistic, with a strong maternal bond but limited care for others. Co-operation in chimps is limited to the violent persecution of other chimps, always to the advantage of the individual. Wolves on the other hand play and raise their young in an extended family structure, take care of their old and wounded and demonstrate emotional distress at the loss of those not related to them by blood. We must not draw too many conclusions from these differences and similarities however as humanity underwent around 5 million years of evolution separate from both chimps and wolves.

Nonetheless it is fascinating to speculate about just how much our humanity has been shaped by our early encounters with wolves. Regardless of who learnt which traits from who the bond between man and dog is undeniably real and powerful. This is extends into the medical world where a good deal of study has been undertaken to examine the medical benefits of living with dogs. There are weaknesses in many studies but arising from the noise we can see decent evidence which suggests that dogs can have a prophylactic and therapeutic value in people. Research has been done to examine if dogs can prevent us from coming ill (unlikely), facilitate our recovery from ill-health (good evidence) and even serve as an early warning system for certain ailments including cancer (unlikely) and oncoming seizures (good evidence). Studies also show reduced systolic blood pressure in dog owners as well as lower concentrations of triglycirides and cholesterol.

In “The domestic dog: its evolution, behaviour, and interactions with people” James Serpell makes the argument that as the utilitarian uses of dogs diminish in the modern age we are beginning to lose sight of the fact that dogs are a truly special and real species of carnivore uniquely adapted for a mutualistic life with humans. We are beginning to see dogs increasingly more like toys and objects of pure affection instead of what they can and used to be, our companions and equals. We force on dogs an unhealthy regime of breeding in order to maintain the idea of purity which results in a wide range of painful and crippling genetic bone disorders. We buy and trade dogs like commodities and give them as presents. In the process we are losing the closest ally in the animal world that we have. Sure, dogs will likely be with us for many thousands of years to come but they are seeming to lose their right to be regarded as a true animal.

I’ll finish with this quote from primatologist Jane Goodall.

“Dogs have been domesticated for a very long time. They have descended from wolves who were pack animals. They survive as a result of teamwork. They hunt together, den together, raise pups together. This ancient social order has been helpful in the domestication of the dog. Chimpanzees are individualists. They are boisterous and volatile in the wild. They are always on the lookout for opportunities to get the better of each other. They are not pack animals. If you watch wolves within a pack, nuzzling each other, wagging their tails in greeting, licking and protecting the pups, you see all the characteristics we love in dogs, including loyalty. If you watch wild chimps, you see the love between mother and offspring, and the bonds between siblings. Other relationships tend to be opportunistic. And even between family members, disputes often rise that may even lead to fights… even after hundreds of years of selective breeding, it would be hard if not impossible to produce a chimpanzee who could live with humans and have anything like such a good relationship as we have with our dogs. It is not related to intelligence, but the desire to help, to be obedient, to gain our approval.”

Wolfgang M. Schleidt/Michael D. Shalter, pg.60 (2003)

References:

http://www.dana.org/news/brainwork/detail.aspx?id=714

http://responsibledog.net/human_dog_bond.html

http://www.nature.com/news/2008/080523/full/news.2008.852.html

Hall MJ, Ng A, Ursano RJ, Holloway H, Fullerton C, Casper J. (2004). Psychological impact of the animal-human bond in disaster preparedness and response. Journal of Psychiatric Practice

Wells DL. (2007). Domestic dogs and human health: an overview. British Journal of Health Psychology
http://www.sciencedaily.com/releases/2010/03/100317144640.htm

Wolfgang M. Schleidt/Michael D. Shalter (2003). Co-evolution of Humans and Canids, Evolution and Cognition

Soohyun Lee1,3* and Simon Kasif (2006). The complete genome sequence of a dog: a perspective. BioEssays

A. PLUSKOWSKI (2006). Where are the Wolves? Investigating the Scarcity of European Grey Wolf. International Journal of Osteoarchaeology

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14 Responses to “In Dog We Trust – The Case For Man’s Best Friend”

  1. A very interesting post. It’s interesting (and disturbing to dog lovers) why some cultures view the dog as unclean (India) or as a food source (Korea). I wonder why such culture differences regarding dogs came about?

  2. > Unlike humans and wolves their social structure is highly individualistic, with a
    > strong maternal bond but limited care for others. Co-operation in chimps is
    > limited to the violent persecution of other chimps, always to the advantage of
    > the individual.

    I think that this perspective misses out on some important details. I don’t think that Jane Goodall meant to say that other chimp relationships are “always” for an individual’s advantage. They may have a tendency to be more opportunistic, but that doesn’t mean they don’t form non opportunistic bonds.

    I recently read a couple of books by primatologist Frans De Waal, “Our Inner Ape” and “Age Of Empathy”. De Waal argues that we should understand primate societies not just by the ways they engage in conflict, but also in the ways that they resolve conflict and maintain social cohesion.

    They’re fascinating books.

    • I agree.

      My statement shouldn’t have been so absolute, as Goodall’s was not. ‘Tends to be more opportunistic and focused on the individual’ is a more accurate description. Every conclusion I draw from chimp comparisons still stands of it’s own accord however.

  3. By coincidence Dr. Steven Novella brings up an interesting point in this blog entry about the perpetuation of juvenile traits (neoteny) in the domestication of dogs. It’s an interesting angle I hadn’t explored and prompts the question of how we should treat our pet dogs, as members of our pack or as children? Is there a significant difference and how do we know which role we are promoting with our actions?

  4. Read Jeremy Taylor’s “Not a Chimp” (His Book-Blog) for some really interesting recent work on how alike and unalike chimps and humans really are. There’s ~12 million years (6 million on each branch) of evolution away from our LCA, so we shouldn’t be so surprised.

  5. michael shalter Says:

    You reference our paper, but give no acknowledgement of the source of the line drawing figure or the origin of GOodall’s quote. The figure was designed by my coauthor, Wolfgang Schleidt, and Goodall’s remarks were in an email addressed to him. For reference, see http://www.uwsp.edu/psych/s/275/Science/Coevolution03.pdf.
    We regret that we had overlooked citing a very imprtant study documenting wolves following herds of barren-ground caribous: Walton et al. 2001. Journal of Mammalogy, 8(3):867-876.
    Furthermore, we point to recent studies showing that herd-following wolves are a separate population, genetically distinct from the resident wolves in areas herds and wolves move through during seasonal migrations.
    We should emphasize, moreover, that reindeer, of course, are not the only ungulates that migrate seasonally in large herds. And herd following by wolves as a model for pastoralism may have started with a number of other species during the Pleistocene or earlier, among ancestors of present day carnivores and ungulates. One wonders how sheep and wolves interacted in good old days before their domestication began?! There are hints that herd following may have been practiced by timber wolves (following buffalo) – and it may still be practiced today. But so far, reindeer in the Asian tundra are the best example of how such a system can work. Apparently it worked quite well in Siberia until the ancient reindeer culture was destroyed by the insane attempt to improve it by the kolkhoz system. At present, with no fuel for herding reindeer by snowmobiles or killing off wolves from helicopters, the wild reindeer are doing well, under the new (old) management of wolves!
    Finally, the role of Neanderthal in human evolution is not resolved, and the naive trust in statistical mean values (e.g. of the dates African Eve and African Adam moved into jolly old Europe) and a disregard of the error limits linger on. Even though prevailing teaching is that modern man and Neanderthal are separate species that did not interbreed, the temporal overlap was considerable. At least, however, the idea that modern man simply exterminated the stupid Neanderthals has been dropped.
    The above remarks are those of Wolfgang Schleidt. I simply edited them
    a bit.

    • Thank you for the first hand insight into your paper Mr. Shalter. I sincerely apologize for not adequately referencing material from your sources and will endeavor to do so when when necessary in future. I hope my edits are satisfactory?

      I believe it is the casual nature of a blog which leads me to only thoroughly reference particular entries. None of this is meant as a technical work, rather as brief exploration of areas that interest me. I do however fully understand that diagrams and direct works should be fully referenced and again apologize for not doing so.

      I’m flattered you’ve taken the time to comment on my blog, even though you may have only done so to address a slight to your work. Your paper was a thoroughly enjoyable read, one of the few papers I devoured in it’s entirety while prepared this entry.

      • m shalter Says:

        Thank you for having responded in a most appropriate way to my remarks. Your edits are quite satisfactory. Thank you
        for having made them.
        I enjoy your blog and hope it will attract many viewers.

  6. Excellent work!

  7. Very interesting! Lots of info I hadn’t seen before!

  8. I really enjoyed this article.

    I train dogs (agility, hunt, and basic obedience) for a hobby. My dogs are also my close companions. I have been fascinated with wolves for as long as I can remember as well.
    I was happy to read about the human – dog hunting symbiosis. Many of the older books and TV documentaries, that I’m familiar with, either don’t address a human – dog hunting symbiosis or describe the domestication of dogs as the taming of wolves for unstated human gains.
    After spending time in the woods with my dogs the human – dog hunting symbiosis seems to be a ridiculously obvious hypothesis.

    I’m looking forward to reading the books and articles that you’ve listed in the references!

    Thanks for a concise and interesting read.

  9. Magnificent items from you, man. I have understand your stuff previous to and you are simply extremely great. I actually like what you’ve bought right here, really like what you are stating and the way in which through which you say it. You make it enjoyable and you still take care of to keep it wise. I can not wait to learn far more from you. This is really a great site.

  10. Hello Michael and Wolfgang(perfect name for your research BTW)
    I am writing a book on wolves Transmissions From the Canid Nation and would like to be in touch with both of you. Could we communicate via email please.
    All Blessings,
    Barbara

  11. Fred Lanting Says:

    Please give me Michael Shalter’s e-mail address. I need to confirm something before I quote it.

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