Wednesday, October 04, 2006

Controversial origins of the domestic dog

My adult education course on tetrapod evolution started this week. While I think it went ok, I hope I didn’t overwhelm my students: the idea for the first teaching session was to quickly run through Palaeozoic and Mesozoic tetrapod history, looking at the major clades, so we dashed through tetrapod origins, lepospondyls, temnospondyls, the living amphibian groups, anthracosaurs, amniote origins, Palaeozoic synapsids, the turtle origins controversy, and diapsid diversity. It will be interesting to see how things progress. The next session covers Mesozoic marine reptiles (excluding plesiosaurs and ichthyosaurs). Meanwhile, I have yet again been tinkering with that big review article on British dinosaurs (now at the final stages of the publication process), and Mike P. Taylor and I have been putting the finishing touches to a paper describing a new sauropod. Other areas of recent interest have been the ‘necks for sex’ hypothesis, Nick Longrich’s paper on ‘leg-wings’ in Archaeopteryx, and gigantic feral cats. More on those subjects in future. Moving on, here at last is that text on domestic dog origins.

Most zoologists ‘know’ that the domestic dog is a domesticated wolf (or, more likely, a number of independently domesticated wolf populations) and so well known is this view that some scientists question the recognition of Canis familiaris as a species separate from C. lupus. This is the ‘mainstream’ view eloquently discussed in several good books on dogs and on domestication, including Olsen’s Origins of the Domestic Dog: the Fossil Record (1985), Clutton-Brook’s A Natural History of Domesticated Animals (1999), and Coppinger & Coppinger’s Dogs: a Startling New Understanding of Canine Origins, Behavior and Evolution (2001). But here’s the news. The ‘domestic wolf’ model is actually not as firmly established as you might think, possibly wrong, and in fact arguably inferior to an alternative model of domestic dog evolution championed by a minority of canid specialists.

Many papers published on the subject of domestic dog origins state flatly that ‘the derivation of domestic dogs from the wolf is well established on behavioural and morphological grounds’, without actually saying in detail what these behavioural and morphological grounds are. It’s certainly true that domestic dogs and wolves are morphologically and genetically similar, but they’re actually also notably different, and while they share behavioural traits, they also differ profoundly in some important respects.

My primary inspiration on all of this has been Janice Koler-Matznick, founder of the New Guinea Singing Dog Conservation Society. Besides publishing important papers on singers (and I won’t be discussing those here: perhaps another time), her experience with them has caused her to re-evaluate theories about domestic dog origins and on domestication. Arguably her most important publication on this subject is Koler-Matznick (2002: free pdf here), which you should see for a good review.

I remain open-minded on the issue of both the phylogenetic affinities of domestic dogs, and on how domestication occurred, and frankly it’s such a huge area that it’s easy to become baffled by the literature. In an effort to keep things as simple as possible I’ve tried to restrict the discussion here to a consideration of one of the central issues: are domestic dogs really part of the species Canis lupus? Let me apologise now if there are areas that I’ve screwed up or misinterpreted, and apologies also to Jan for ‘borrowing’ her ideas so heavily.

Are domestic dogs really wolves? Some very obvious things to consider

As a rough rule of thumb, the domesticated forms of wild mammal species (1) revert back to wild-type after being feral for a few generations, and (2) readily interbreed with their wild ancestors. If domestic dogs are wolves, then the many populations of feral dogs that live world-wide should theoretically have reverted back to being wolf-like in appearance and behaviour. But they haven’t. Instead, domestic dogs always end up looking like pariah dogs – the relatively small (11-16 kg), socially flexible semi-domesticated and feral dogs of the Old World tropics. Dingos and the unusual New Guinea singing dog are part of the pariah dog complex, though the singing dog is so odd in behavioural, molecular and morphological features that it might warrant specific status (Koler-Matznick et al. 2001, 2003).

Archaeological data shows that pariah dogs have a stable history, with dog skulls from 4000 year old deposits in Thailand being essentially identical to the modern dingo-like pariah dogs of the area. Until relatively recently, domestic dogs must have been free-ranging and hence would have had ample opportunity to interbreed with wolves. While this has certainly happened on many occasions (modern wolf/dog hybrids are known from North America, Italy, as well as from archaeological samples*), what is surprising is that it hasn’t happened more often. This isn’t the case in other domesticated mammals, where interbreeding with wild ancestors is widespread.

* Some coyote populations have also been shown to include genetic data from domestic dogs (Adams et al. 2003).

In Europe, wolves remain only as endangered, fragmented populations vastly outnumbered by domestic dogs, and there has long been concern that wolves will be genetically swamped through interbreeding with dogs. Actually, there is no good evidence for this, and in a recent study of Italian wolves Verardi et al. (2006) found the two to have distinct gene pools, that hybridization had occurred only very rarely, and that introgressive hybridization between the two is so limited that it doesn’t pose a threat to the genetic integrity of the wolf. Wolves and domestic dogs are in fact staying distinct. This applies globally as well as locally: despite continuous, near-global sympatry between domestic dogs and wolves, hybridization has hardly occurred and only one mtDNA type is shared. On this basis Koler-Matznick (2002) argued that domestic dogs and wolves satisfy the biological species concept and shouldn’t be regarded as conspecific.

While (to my knowledge) no-one doubts the idea that domestic dogs and wolves are close relatives, firm evidence showing that domestic dogs are nested within the species Canis lupus is lacking. Attempts to genetically link domestic dogs to living wolf populations failed to find a match, making the hypothetical wolf ancestor of the domestic dog a mystery. Morell (1997) wrote of the University of California’s Robert Wayne, a leading researcher in this area, that ‘Although he sampled as many wolves as possible, it may be that the ancestral wolf population is now extinct’ (p. 1647). Of interest here is that the wolf most often cited as a potential domestic dog ancestor, the Indian peninsular wolf C. l. pallipes, has recently been shown to represent a radically unique, divergent lineage that is quite distinct from other wolves, and from domestic dogs (Jhala & Sharma 2004).

The implication from these lines of evidence is that domestic dogs descend from an ancestral pariah-like form which was quite different from wolves and that, while domestic dogs and wolves are closely related, they are distinct. Domestic dogs seem to have an independent history of descent and do not simply merge into wolves when the opportunity arises.

Wolves are behaviorally ill-suited for domestication

According to the conventional theory of dog domestication, wolves were domesticated either to function as big game hunters, or as guards. But here there are problems. If wolves really were domesticated prior to about 10,000 years ago (more on this date below), the earliest domestic dogs would have been living alongside people that were using clubs, spears and other such tools to subdue large prey, and therefore hunting via stealth and ambush. This poses a problem for the idea that people domesticated dogs to assist in large game hunting, as the chasing behaviour instinctive to wolves would presumably hinder human hunting efforts. Even in dingos we find that they’ve apparently always been preventing from participating in aboriginal kangaroo hunts because their chasing behaviour made the hunts a failure*. People would also have to pretty much fight with wolves in order to get any game animals back off them, given that wolves are highly food-possessive.

* I know that some hunting humans are outstanding long-distance runners that pursue wounded prey over km, and might theoretically benefit from canid assistance, but there is no evidence that this hunting strategy was widespread among ancient people. So far as we know it is limited to southern Africa (correct me if you know otherwise).

The possible use of wolves as guards is also problematical, given that wild canids function poorly in this role. Rather than defend a location, they will clear off when danger threatens, even if that location is their own den (including offspring). Sure, wolves might make some useful alerting noise if intruders were to come around, but other canids and other animals do this equally well.

While they can be tamed, wolves are actually very difficult to train. This probably results from their social system: only the dominant pair in the pack reproduces, and consequently there is an imperative to employ aggression to move up the pack hierarchy. These points don’t make wolves seem like ideal animals for domestication. Indeed, the fact that domestic dogs don’t form hierarchical packs makes them decidedly unwolf-like and it has been argued that the flexible social structure and high tolerance of domestic dogs to gregariousness suggests derivation from a canid that didn’t have a wolf-like hierarchical pack (Koler-Matznick 2002) [adjacent image depicts a dingo].

It is becoming increasingly recognized that dogs are remarkable among mammals in exhibiting human-like social skills and communicative behaviour (Hare et al. 2002). More so even than chimpanzees, dogs can reliably interpret human acoustic and visual cues (e.g., pointing or nodding), they have an inherent understanding of human perception, and they can even use human-like gestures, such as pointing. The presence of these social skills in domestic dogs might suggest that humans and wolves developed a communicative bond early on, and that this facilitated or initiated domestication. However, wolves have been studied in this context and have been found to lack the social skills and communicative behaviour that characterizes domestic dogs, so the social skills of domestic dogs presumably arose during domestication. This is supported by the fact that the domesticated foxes bred by Dmitry Belyaev and his team match domestic dogs in their ability to recognise human visual cues (I don’t want to discuss Belyaev’s fascinating experiment here as it would involve adding too many words: see Trut 1999).

Might wolves have domesticated themselves?

In view of these problems and others, those workers supporting the wolf hypothesis have argued that wolves domesticated themselves: by scavenging around camps and villages they became human commensals and eventually evolved into pariah dogs. As a relatively large (20-55 kg) predator it is difficult to imagine that wolves might have integrated into human society in this way. Notably, those carnivoran species that have become human commensals are all generalized omnivores smaller than most wolves: raccoons Procyon lotor, Red foxes Vulpes vulpes, Golden jackals Canis aureus and coyotes C. latrans.

Furthermore, it has been argued that the human camps hypothesized as the earliest places frequented by hypothetical commensal wolves would not have produced the waste that a large predator would require in order to make that fundamental niche shift. It is also worth noting that wolves were almost certainly a very real danger to prehistoric people and that they would have been regarded as enemies, not as potential friends.

Given that domestic dogs were apparently domesticated multiple times in various places, it is difficult to accept that so many wolf populations became amenable to domestication when these problems exist.

Morphologically, are domestic dogs really wolf-like?

It has long been recognised that domestic dogs differ from wolves in a number of detailed skull characters. Compared to wolves, domestic dogs are smaller and have proportionally smaller teeth, a wider palate, broader braincase and higher frontals, and smaller, less rounded auditory bullae. Mostly these differences have been explained as the result of either reduced selection under domestication (Björnerfeldt et al. 2006), or artificial selection for neotenous characters. There are however a few features present in domestic dogs (and not in wolves) that can’t be easily explained this way, such as the difference in the shape of the mandibular coronoid process.

While these characters might result from reduced selection under domestication, or artificial selection for neotenous characters, it’s interesting that many of them recall the conditions seen in non-wolf canids, such as jackals and dholes. Indeed some authors have concluded that domestic dogs are less like wolves than they are like these other wild canids (Manwell & Baker 1983, Wayne 1986, Koler-Matznick 2002). In fact we don’t know that the apparent neotenic features of domestic dogs result from artificial selection, given that neoteny can arise via other means, and it should at least be considered that the unwolf-like characters present in domestic dogs indicate derivation from a non-wolf ancestor.

A fairly logical assumption that one might make, were the ‘domestic wolf’ model valid, is that the most primitive domestic dogs (viz, those that had been exposed to the least amount of artificial selection) would be the most wolf-like of them all. This would apply both to fossils, and to the most primitive living breeds. As hinted at above however, archaeological specimens show that old dogs are pretty much the same as modern pariah dogs - there isn’t a series of specimens morphologically intermediate between wolves and domestic dogs - while the most primitive living domestic dogs, the dingos and New Guinea singing dogs for example, are not wolf-like but quite distinct from them behaviourally, socially and morphologically.

Domestic dogs: ancient and genetically distinct

If domestic dogs are wolves, you would expect the two to be very close genetically, certainly closer than universally recognised non-domesticated carnivoran taxa. Surprisingly for the dogs-are-wolves model, this is not true. In fact domestic dogs and wolves are (based on allozyme electrophoresis) further apart genetically than are leopards and jaguars, and (based on DNA hybridization) further apart than some bear species (Wayne et al. 1991).

A major analysis of mitochondrial DNA in domestic dogs worldwide (sampling 67 breeds as well as wolves from 27 localities) found most domestic dogs to belong to a ‘divergent monophyletic clade* sharing no sequences with wolves’, but with some domestic dog clades including some wolf haplotypes, apparently resulting from recent hybridization (Vilà et al. 1997). These authors concluded from mitochondrial and nuclear genes that domestic dogs were ancient, and that they had repeatedly interbred with wolves at various times and places throughout their history. This could be consistent with a derivation of domestic dogs from wolves, but equally it could merely show that hybridization has occurred at various times and places and it may be uninformative as regards ancestry. Indeed we know that several wolf-like domestic dog breeds (e.g., Saarloos wolfhound, Czech wolfhound, American tundra shepherd, American timber shepherd) were produced by deliberate crossing with wolves.

* The term ‘monophyletic clade’ is redundant given that a clade, by definition, is monophyletic. Included especially for Mike P. Taylor :)

The hardest bit of this story to accept is just how ancient these authors propose domestic dogs to be: the answer is more than 100,000 years old. Well, we modern members of Homo sapiens are meant to be about that old (give or take 50,000 years), so if that date is accurate, we must have started domesticating dogs as soon as we got out of Africa. Archaeological evidence for domestic dogs extends back to 14,000 years (based on a jaw from Germany) and other studies have suggested an origin at about 15,000 years ago (Savolainen et al. 2002). Less securely identified alleged domestic dogs from Russia are perhaps 17,000 years old, but there are no remains approaching 100,000 years in age.

While there are good reasons for thinking that the domestication of dogs probably extends beyond 15,000 years ago (perhaps to, say, 40,000 years or so), the lack of domestic dog prototypes in the archaeological and fossil record has been a problem. Some supporters of the ‘domestic wolf’ model have argued that we haven’t discovered wolf-dog intermediates because, prior to about 15,000 years ago, domestic dogs were morphologically indistinguishable from wolves. Unfortunately that is totally incompatible with the idea that wolves became domesticated after adopting a jackal-like commensal niche, as strong reduction in size is a requirement for the latter theory.

What might be a domestic dog prototype is known from strata extending back to 200,000-500,000 years however, and this is the extinct Chinese canid named C. l. variabilis Pei, 1934. Though classified as a small wolf, this form resembles domestic dogs in small size, detailed mandible shape and other features. Intriguingly, it appears to have been common and morphologically distinct for tens of thousands of years over a wide geographical area, despite sympatry with ‘normal’ C. lupus (Olsen 1985, Koler-Matznick 2002). Olsen has noted (pers. comm. cited in Koler-Matznick 2002) that the referral of C. l. variabilis to C. lupus was never satisfactory, and given the features mentioned here it is conceivable that this dog-like form was not really a wolf, but either a separate species ancestral to the domestic dog, or an early representative of C. familiaris.

If domestic dogs aren’t wolves, what are they?

All of this begs the question: if domestic dogs aren’t wolves, what are they? The answer seems to be that Canis familiaris is a distinct species with its own independent history. Prior to domestication, it presumably existed as a relatively small, generalized canid that voluntarily adopted the commensal pariah niche still occupied by many dog populations today. This is supported by the morphological and molecular distinctiveness of domestic dogs, by the anatomy and behaviour of primitive domestic dog breeds, and by the archaeological and fossil record.

If this is true then the truly wild ancestors of modern domestic dogs are extinct. True, there are wild pariah-type dogs in various places around the world (there are wild populations of New Guinea singing dogs and dingos, for example), but they’ve been introduced by people. However, the lack of the original wild form in a species that has become domesticated or at least semi-domesticated is not unprecedented nor unusual: Dromedaries Camelus dromedarius, for example, only exist in the wild today in feral form, and are otherwise entirely domesticated, and the wild ancestors of modern domestic horses and cattle are entirely extinct. In fact the eradication of the wild ancestors of a domestic form is thought by some to one of the key historical events that occurs during the domestication process (Dobney & Larson 2006).

The theory that domestic dogs descend, not from wolves, but from a wild Canis familiaris remains unpopular and overlooked, and even today relatively few zoologists are aware of the literature on this ‘alternative’ view of domestic dog origins. As mentioned earlier, my primary inspiration in this area has been Janice Koler-Matznick and her papers, and I have only scratched the surface in terms of the information she has provided. I’ve also avoided discussion of many other fascinating areas involved with this debate, such as Belyaev’s farm-fox experiment and the morphological and physiological changes observed in his domesticated foxes, theories on the domestication and/or transportation of grey foxes, South American foxes and other species, the diversity of the different domestic dog clades, controversies over the origin of pre-contact American dogs such as the Xoloitzcuintli, and David Paxton’s theory that the incorporation of dogs into human society resulted in morphological changes in humans.

It’s a lot to think about.

PS - you might have noticed that the font size and font type varies in the text above. I have NO idea why this is and have done all that I can to correct it (I've spent an hour trying to iron things out by messing with the html).

For the latest news on Tetrapod Zoology do go here.

Refs - -

Adams, J. R., Leonard, J. A. & Waits, L. P. 2003. Widespread occurrence of a domestic dog mitochondrial DNA haplotype in southeastern US coyotes. Molecular Ecology 12, 541-546.

Björnerfeldt, S., Webster, M. T. & Vilà, C. 2006. Relaxation of selective constraint on dog mitochondrial DNA following domestication. Genome Research 16, 990-994.

Dobney, K. & Larson, G. 2006. Genetics and animal domestication: new windows on an elusive process. Journal of Zoology 269, 261-271.

Hare, B., Brown, M., Williamson, C. & Tomasello, M. 2002. The domestication of social cognition in dogs. Science 298, 1634-1636.

Jhala, Y. & Sharma, D. K. 2004. The ancient wolves of India. International Wolf Summer 2004, 15-16.

Koler-Matznick, J. 2002. The origin of the dog revisited. Anthrozoös 15, 98-118.

- ., Brisbin, I. L., Feinstein, M. & Bulmer, S. 2003. An updated description of the New Guinea singing dog (Canis hallstromi, Troughton 1957). Journal of Zoology 261, 109-118.

- ., Brisbin, I. L. & McIntyre, J. K. 2001. The New Guinea singing dog: a living primitive dog. In Crockford, S. J. (ed). Dogs Through Time: An Archaeological Perspective. BAR International Series 889. Archaeopress (Oxford), pp. 239-247.

Manwell, C. & Baker, C. M. A. 1983. Origin of the dog: from wolf or wild Canis familiaris? Speculations in Science and Technology 6, 213-224.

Morell, V. 1997. The origin of dogs: running with the wolves. Science 276, 1647-1648.

Olsen, S. J. 1985. Origins of the Domestic Dog: The Fossil Record. The University of Arizona Press, Tucson.

Savolainen, P., Zhang, Y.-p., Luo, J., Lundeberg, J. & Leitner, T. 2002. Genetic evidence for an east Asian origin of domestic dogs. Science 298, 1610-1613.

Trut, L. N. 1999. Early canid domestication: the farm-fox experiment. American Scientist 87, 160-169.

Verardi, A., Lucchini, V. & Randi, E. 2006. Detecting introgressive hybridization between free-ranging domestic dogs and wild wolves (Canis lupus) by admixture linkage disequalibrum analysis. Molecular Ecology 15, 2845-2855.

Vilà, C., Savolainen, P., Maldonado, J. E., Amorim, I. R., Rice, J. E., Honeycutt, R. L., Crandall, K. A., Lundeberg, J. & Wayne, R. K. 1997. Multiple and ancient origins of the domestic dog. Science 276, 1687-1689.

Wayne, R. K. 1986. Cranial morphology of domestic and wild canids: the influence of development on morphological change. Journal of Morphology 187, 301-319.

- ., Van Valkenburgh, B. & O’Brien, S. J. 1991. Molecular distance and divergence times in carnivores and primates. Molecular & Biological Evolution 8, 297-319.


Anonymous Anonymous said...

An interesting post, but I have to tell you it's also a deeply puzzling one, because it flatly contradicts a number of things I thought I knew about dog evolution, based on both personal observation and several authors who have a reputation of generally getting things right. For example:

1) however old Man's presence in the New World is, the domestication of the dog must be even older, because Amerinds brought dogs with them.

2) hybridization between species of bears or big cats is rare, but hybridization between dog and wolf is common. As far as I know, such ready hybridization occurs only between members of the same species or species-swarm.

3) in his book The Truth About Dogs, Stephen Budiansky reports results of an mtDNA study by Robert Wayne that showed dogs and wolves are more similar in their mtDNA than are wolves and coyotes. If the mtDNA clock is right, and the fossil record for the wolf/coyote split is accurate, the wolf-dog split is no more than 135,000 years old, and wolf and dog share a huge number of distinctive mtDNA markers.

You wrote: [[ A fairly logical assumption that one might make, were the ‘domestic wolf’ model valid, is that the most primitive domestic dogs (viz, those that had been exposed to the least amount of artificial selection) would be the most wolf-like of them all. ]]

Question: How do you tell what the "most primitive" dogs are, if you don't know where or from what ancestors dogs originated? Which is "more primitive," the New Guinea singing dog, the dingo, or the (frequently outcrossed to wolves) Alaskan husky?

You also wrote: [[ Indeed, the fact that domestic dogs don’t form hierarchical packs makes them decidedly unwolf-like ]]

This is nonsense. Hierarchical pack behavior is common in domestic dogs. I have seen it firsthand in dogs my family has owned. And the pack-behavior meme is a common -- and almost invariably successful -- way to interpret dog behavior and control the training process.

4:04 AM  
Blogger Steve Bodio said...

Brilliant, Darren! It fits well with research I have been doing but takes it quite a but further. I'll write you more when I have thought about it.

"Point of origin" looks to be my area of fascination-- Central Asia/ south Siberia/ Altai-- which could go with western China. Do you know about the mandible that Christy Turner found in the Altai a couple of years ago? (14,000 years old I think).

Re runners-- the Tarahumara in northern Mexico are said to run down deer even today.

2:50 PM  
Blogger Laura Knight Jadczyk said...

I think this is fascinating, and thank you! As the "parents" of an almost human Sheltie, my husband and I often wonder how such a creature could come to be who is so absolutely remarkable. He has required almost no training at all, he just learns to do amazingly appropriate things because he is constantly "reading" the people in the family.

Meanwhile, a friend of ours in Marseille visits now and again and brings his dog that does "sing." Strangest dog I've ever seen. He is from Australia, I believe, but he's not a dingo. This dog, too, is entirely focused ALL the time on his "human."

3:21 PM  
Blogger Webs said...

I haven't ever done the research into this, but it's always seemed to me that coyotes and/or jackals are much more dog-like than wolves in gross morphology and behaviour.

Has anyone come up with a rigorous cladogram, whether based on anatomy or genetics?

4:28 PM  
Anonymous Anonymous said...

Excellent article. The ramifications of the age of domesticated dogs being much odler than previously thought is profound, and perhaps with the date of agriculture being re-examined, many more aspects of what we consider modern human behavior will need to be re-examined as well.

5:30 PM  
Blogger David Lee Ingersoll said...

This makes a lot of sense. You've suggested an answer to a mystery that I wasn't even aware of. Thank you for writing and posting this.

5:43 PM  
Anonymous Anonymous said...

Hi, I really enjoyed this excellent article.

As someone who takes a strong amateur interest in biology, I'd thought that the whole dog-from-wolf debate had been "settled" by removing the species distinction of canis familiaris! I'm pleased to learn that the matter is far from resolved.

Two additional points: i) the home territory of the pariah dogs and dingos, singing dogs, etc. seems to be Indonesia and perhaps South-East Asia. Surely it can't be coincidental that several other domesticated species (I'm thinking chickens and pigs) also seem to originate from here?

ii) Several other domestic animals, esp. cattle, have unidentified wild ancestors or claimed ancestors like aurochs that don't quite "fit the bill".

7:10 PM  
Blogger youcantryreachingme said...

Font looks ok to me.

I appreciate the depth of your summary articles (such as this one).

You mentioned aspects of the skulls of dogs - various features which differ to wolves. Do you mean to say, then, that across *all* dog breeds, those same features are actually consistent?

I am very unfamiliar with dogs as a topic, in the way discussed here, but I would be surprised to learn that there are morphological aspects to dog skulls (or other anatomical features) which are *consistent* across all breeds, yet consistently *different* from other species. Can you delve a little deeper on this?

5:03 AM  
Anonymous Anonymous said...

Why not multiple origins for the domestic dog? Isn't it probable that at least some of the Northern breeds are wolf-descended? Their appearance combined with the unlikeliness of a pariah-type dog population existing in the wastes of the Arctic suggest this. Plus behavior: I have a Siberian Husky-they are known to be lousy guard dogs-who barks only when she wants to play, never as an alarm. Isn't the simplest explanation for this breed's origins the capture of wolf pups for future use as draft animals and then selective breeding to eliminate the aggressive and the lazy. Mine-like most Sibes-loves to run and is nonagressive towards all other dogs. Her extreme affection for children is also notable.That that must been a real plus for Arctic village life-the dogs can keep in prime condition while running around camp when not pulling with no danger to the little ones.

The Congo's Basenji may be the candidate for least likely to be descnded from wolves. The nearest wolf population is very far away in Ethiopia. Then again I think there is a theory that the Basenji originated in Egypt and came to the Congo via trade routes. I don't buy it.

5:46 AM  
Blogger Dr. Vector said...

This is extremely interesting stuff. I know zilch about the origins of domesticated animals, but it immediately makes me curious about the origin of cats. And also about how cats fare when they're cut off from human commensalism. Do feral cats make it in the long run--do they form truly wild populations of "pariah cats"?

In any case, you've proven once again that even the most seemingly mundane animal can be the tip of an iceberg of interesting phenomena.

Keep 'em coming.


8:00 AM  
Anonymous Anonymous said...

This is a wonderfully deep review. But its tone that any of this is surprising, seems to miss the mark a bit. Far more common in this literature in recent years is the phrase "wolf-like ancestor" rather than "descended from wolves." Thus, I don't think any of the scientists cited would disagree with your essential message. But this review helps the popular literature catch up with this important distinction.

Genetics says unequivocally that pariah dogs and gray wolves have a common ancestor. Any amount of reticulate evolution during that split would be hard to assess, and easily obscured by strong, divergent selection on the dog lineages.

An unresolved confusion reigns here, however. The review does not distinguish between *degree of divergence* and *position of the evolutionary branch point*. The fact that feral dogs don't revert to wolves speaks to the former but not the latter, and anthropogenic selection only exaggerates that *degree* of divergence. Another comment above pointed out that other domestic species, including cattle, have no "wild surviving ancestor." The *common ancestral species* is always extinct, because both have evolved since the split.

Finally, I think the fine points about wolf and dog behavior differences carry little weight compared to the fundamental similarities in social cooperation.

5:50 PM  
Anonymous Anonymous said...

Fascinating stuff. In a similar vein, I had read somewhere that certain domesticated varieties of chicken (the Asiatic class, to be precise) had an ancestor that wasn't Gallus gallus. It was dubbed "Gallus gigantus" or "Gallus giganticus"--something along those lines. Apparently, differences in skull structure led to this idea. Whether it has any merit is another tale altogether.

10:49 PM  
Blogger John S. Wilkins said...

I blogged this on my site too.

If the Austraian dog Laura referring to is the "blue heeler" (a cattle dog) it is part dingo, I believe.

4:25 AM  
Anonymous Anonymous said...

Wolfwalker wrote
"This is nonsense. Hierarchical pack behavior is common in domestic dogs. I have seen it firsthand in dogs my family has owned."

???????? I've had large groups of dogs (a few males and females at the same time) and I've never seen this. There is a well defined "pecking order" but there is no such thing as an alpha breeding pair. Femeales do not hinder reproduction of other femeales, and if given a chance they try to mate outside from the group. The question is if wild dogs like dingoes have an alpha pair.

Thanks for the nice article Darren, and for the references, I'll have to check them, particularly the ones about singing dogs. I've seen some time ago a documentary about baboon troups living in garbage dumps who took dog pups into their groups. They sort of protected their baboon family at night. That ought to be published somewhere.

4:57 AM  
Anonymous Anonymous said...

My casual understanding was that the basic wolf-dog hybrid has a mating season (unlike dogs) that doesn't overlap with that of the parent wolves. Thus, since interbreeding can only go "to the dogs", they weren't considered "fully interfertile", thus separate species.

5:06 AM  
Blogger Somal Thakore said...

Intersting reference to your work and the writings.
keep it up.

4:33 PM  
Blogger Craig Pennington said...

Regarding hunting by running down prey, Bernd Heinrich in Why We Run: A Natural History talks about a natie American (I don't recall more specifically than this) method for obtaining a sacred deer hide that involved running the deer to exhaustion and suffocating it. This method of hunting was not typical for food acquisition, though.

6:49 PM  
Anonymous Anonymous said...

Then there is the "Carolina Dog" see wikipedia. It may be one of the domestic dog's wild ancestors.

6:39 PM  
Anonymous Anonymous said...

Looking for the Wikipedia article on the Carolina Dog, I found the Wikipedia article on dog origins. It's pretty interesting.

3:15 PM  
Anonymous Anonymous said...

Great Work Darren

I have just been lecturing my (adult)students in the UK on the history of the dog - and my first question to them is - who is the ancestor of the dog - and everyone of them said the wolf.
When I ask them why they say that - they always refer to 'scientist'. I spent three hours looking at the similarites of canids - and getting them to try and justify the wolf theory. At the end of the session they all changed their minds and are now open to lookng at other ideas.

It will be nice to point them to this sight for alternative view points.



1:21 AM  
Blogger Frank said...

Late to the party, so no one will probably even see this, but oh well. Earlier in the week, I read an article on the BBC's website about a highly endangered Ethopian canid (I think they said it was a wolf, but I don't want to be inaccurate) and the pictures of it looked an awful lot like the pictures of dingoes, singing dogs, and pariah dogs I've seen. It also seemed to have a different sort of society and psychology than "typical" wolves, more in keeping with dogs. Could humans, who also evolved in that area, have domesticated this species?

12:02 AM  
Anonymous Anonymous said...

I have no position on this matter, but do need to present some info contrary to Naish's original Oct. 04, 2006 post. Two points:

(1) In Naish's paragraph beginning "While they can be trained ..." he presents the old view about wolves that "only the dominant pair breeds, and about the wolf's need to move up the dominance hierarchy. Granted I published those concepts in my 1970 book "The Wolf," but I have since corrected them in my 1999 Can. J. Zool. article "Alpha status, dominance, and division of labor in wolf packs," which can be accessed on my website (

(2) Naish's paragraph on date of dog domestication, starting with "The hardest bit of this story ..." overlooks Wayne's 2003 admission (p. 225 in Mech and Boitani "Wolves") that his genetic dating "can be consistent with a single origin from East Asia about 15,000 years ago (Savolainen et al. 2002)." The article by Savolainen et al. is in Science (298:1610-1613).

Dave Mech

8:54 PM  
Anonymous Anonymous said...

I've always been sceptical of the grey wolf ---> dog theory. IMO domestic dogs are a mix of many different populations of Canis Lupus (such as C. l. variabilis) and closely related species, not just the C. lupus populations we label as "grey wolves."

9:09 PM  
Anonymous Anonymous said...

Frank --

That animal is the Ethiopean wolf. I wonder if it is significant that one of the biggest threats to the Ethiopean wolf is hybridizing with domestic dogs, according to the one and only television program I have ever seen on the species. Apparently dogs readily join Ethiopean wolf packs and breed with them, and there are many "wolves" with suspiciously dog-like features such as oddly colored coats and unusual fur.

The Ethiopean wolf has different social behavior from the gray wolf: pack members hunt alone for rodents, and come together mainly to defend their territory from other packs.

5:10 AM  
Blogger Sue said...

Daren, well argued. Your arguments are pretty much the school of thought running through academia at the moment. I notice you referenced dear old James S - the anthrozoological bible!

Yes, the evolution of the domestic dog originating from the wolf is often perpetuated in the popular dog world - dog trainers, showers etc. Academic thought is very different and you've cracked it!

keep up the good writing

3:20 AM  
Anonymous Anonymous said...

We all know that the dog is not descended primarily from the jackal. But has the possibility of any jackal ancestry in the domestic dog been ruled out by genetic studies? Reportedly, jackals can be domesticated to a degree impossible with wolves.

While jackals are wolf- and dog-aversive naturally, so are coyotes. I've read that Plains Indians used to obtain dog-coyote hybrids by tying bitches in heat to stakes in areas frequented by coyotes. Needless to say, it was a hit-and-miss procedure and the bitch might be attacked, but hybrids were obtained periodically.

I wonder if a similar process could not have enabled domestic jackals to be bred against the small wolves of the Old World tropics. Over time, the best hybrids might have been much more wolf than jackal overall while retaining certain jackal behavioral characteristic.

Interestingly, jackals and dogs are currently being hybridized by the Russians as detection dogs. The Russians claim that jackals have a superior sense of smell compared to most domesticated dogs. The jackals are mated to huskies who have more tolerance for the cold weather in which the hybrids are expected to work. That leads me to wonder if the jackal's easy domestication and sense of smell could have been useful to early humans in some way. Jackals are often reported to be much more "cowardly" animals than wolves and dogs. Could a less timid animal with an excellent sense of smell have been useful in hunting?

3:41 AM  
Blogger Michael said...

Very informative and thought-provoking post.

4:52 PM  
Anonymous Anonymous said...

On a photo safari in Botswana last year I saw a pack of animals the guide identified as "wild dogs". They certainly looked more dog-like than wolf-like. The guide mentioned that only the alpha male and alpha female mated. Are these the pariah dogs you are talking about? I have some pictures of them if you would like.

Also, it seems kind of important in this discussion to know whether or not a dog pack formed from formerly domesticated dogs will revert to the behavior where only the alpha pair mates. I don't know if a dog pack has ever existed long enough to observe this, though.

Thanks for a really interesting article.

Allan Miller

7:54 PM  
Blogger Luigi said...

Very interesting. Linked to here Of course, extinct wild relatives are also not unknown among domesticated plants.

2:22 AM  
Anonymous Anonymous said...

Interesting that you leave out a Wayne paper that doesn't support your argument, quote: "The domestic dog is an extremely close relative of the gray wolf, differing from it by at most 0.2% of mtDNA sequence15,22,23."

But then you did the same with Dave Mech's work as well, as he pointed out...

8:16 PM  
Blogger Darren Naish said...

Whoops. I am more than happy to be swayed by additional data, and agree that this is a serious oversight.

9:08 PM  
Blogger SmileSleep said...

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7:19 AM  
Anonymous Anonymous said...

Suggested reading: "Determining the Antiquity of Dog Origins" by Michelle J. Raisor, 2005. Explains a lot of the unexplained :)

2:04 PM  
Blogger BorderWars said...

"the fact that domestic dogs don’t form hierarchical packs makes them decidedly unwolf-like"

Fashionable Dog training pseudo-dog-psychology (i.e. be your dog's pack leader and all will be well and good in the world) aside, I'd hope you could expound on the above statement.

Personal experience with my own gang of dogs seems to correlate with several behaviors I've seen in Wolves and Meerkats on TV. I'd go so far as to say that I can identify the hierarchy and the behaviors my dogs use to reinforce it.

I realize that TV shows are edited and narrated to provide a compelling story and a spoon fed interpretation of the video, and given 1,000 hours of footage of meerkats I could probably convincingly retell Hamlet, Rent, and West Side Story.

But I'm curious about feral dogs and their "pack structure" and if in-home domestic dogs also portray many of the same behaviors, and when they deviate, if it isn't us humans that aren't fulfilling our role in the pack hierarchy.

12:14 AM  
Anonymous Anonymous said...

I tend to agree with the author. If my Ridgeback were directly related to a wolf he would have a larger brain and therefore be capable of opening every door, drawer and box in my house in his search for food. Oh wait a minute...he already can do that.

2:05 PM  
Anonymous Anonymous said...

Very interesting.

4:48 PM  
Blogger Unknown said...

Very interesting blog, and I have to agree with a lot of what the author is saying. I also wanted to respond to a couple of comments from Wolfwalker:

"2) hybridization between species of bears or big cats is rare, but hybridization between dog and wolf is common. As far as I know, such ready hybridization occurs only between members of the same species or species-swarm. "

In captivity, hybridization between large cats that are cohabiting is quite common. In the wild it is less common, presumably because tigers and lions don't have the chance to encounter each other on the serengetti.

In canids it works the same way. In captivity with human guidance canids hybridize readily, but in the wild it is quite rare despite their close proximity to one another. Wolves and dogs are much more likely to kill and EAT each other, than try to breed.

Hybridization between domestic cattle (Bos taurus) and wild American bison (Bison bison) happens far more readily than wild wolf/feral dog hybridization, and they aren't even members of the same genus. I personally find it hard to believe that two animals purported to be members of the same species would have such difficulty reproducing in the wild.

And Alaskan huskies are not that commonly hybridized with wolves. At least, not by working husky kennels. High content wolf hybrids make terrible sled dogs.

"This is nonsense. Hierarchical pack behavior is common in domestic dogs. I have seen it firsthand in dogs my family has owned. And the pack-behavior meme is a common -- and almost invariably successful -- way to interpret dog behavior and control the training process."

Not like wolf behavior. If you think that your intact lower ranking dogs would not breed a female in season because you are the alpha, then you are deluded. There are some very major differences in social behavior. Also, the TV personalities who promote dog training methods based off wolf behaviors such as alpha rolling are idiots. Any trainer who is familiar with the most current research in animal behavior knows that those methods are out of date and dangerous. To be an effective leader for a pack of dogs all you must do is control their resources, not bully them into submission.

7:56 PM  
Anonymous Anonymous said...

The whole Dogs as wolves in training and and behaviour makes for good TV but not for good dog training.

Copinger is a good read for those who would like more info (studies on the behaviour of Pariah dog) It is found that dogs in the natural state are scavengers more than hunters, and while they might pack up occasionally, the groups are fluid and don't have regular members. Pariah dogs are social but not pack animals.

This myth that dogs are pack animals and that wolves are good models for behaviour is now such an issue (thanks to shows like the Dog Whisperer.. ) that more and more professionals and organizations are speaking out. The American Society of Veteranarian Animal Behavoir has sent out a statement asking vets not to recommend trainers who promote pack/dominace myths. That article is worth reading as there are some direct wolf/dog comparisons.

There is also a response from the head of animal behaviour from Purdue University to a tape he was sent of the "dog whisperer" In his response he states his dismay of the promoting of pack theories with dogs.

So it comes as no surprise to the dog training community that dogs might not come from wolves.

1:51 AM  
Anonymous Jane said...

As a dog owner (greyhounds) & aspiring animal behaviourist, both the original post & the comments which follow make very interesting reading.

2:10 PM  
Blogger — Kim said...

Hey, interesting blog! And interesting post about the origins of the domestic dog.

Check out my new blog: Top Dog Blog!

It's still pretty new, but I'll be adding new content and pictures daily.


See you there!

11:33 PM  
Anonymous Anonymous said...

I disagree with the ideas of previous commentor that dogs are scavengers rather than predators. Perhaps they are less suited to cooperative large game hunting such as some populations of wolves, but their smaller size and greater agility suits a more individual hunting style such as that of the ethiopian wolf. I have often turned my back for only a few moments and my dog has caught gophers and ground squirrels, I would suggest this is their more natural prey base (Obviously this is not to imply that they are not capable of cooperative hunting). But My uncle had a farm dog husky that rarely ate its dogfood and most often fed itself on fresh meat which it had caught alone.

7:24 PM  
Blogger Robert said...

A most interesting article and one that has gone some way to justifying my misgivings about current accepted theories.

I'm not a scientist but have a real interest in training my dogs in a sympathetic kind way, to me basing training a domestic dog on research done with captive wolf packs is just incredibly wrong considering the different behaviours between the two what seem quite obviously two different species.

Moving on from that I believe the current proliferation of behaviourists trained with wolf behaviour as a foundation are creating a smoke screen and slowing down the process of understanding the real character of the dog.

Excellent blog,I look forward to researching your references.

Thank you.

1:45 PM  
Blogger Leiha Noriega said...

Thought provoking insight. I am most certainly late to the party but am so glad my initial responses to the original post were voiced. Dave Mech, I GREATLY enjoyed your article and have been dismayed at how many still promote the dominance-based theory.

I stumbled upon the post on accident while searching for the answer to the question of optimal food sources and amounts for domestic dogs (by hopefully determining its wolf-like ancestor's name and therefore the ancestor's diet) and most of the recommendations I've found thus far have been modeled after wolf diets. Does anyone have solid information on this either in support or opposition? I am aware of the Wayne paper and thank you for mentioning it earlier.

8:56 AM  
Anonymous Dog Beds said...

That was a very good information to us pet lovers. Now I know the origin of domestic dog now. I learn more things on the post.

7:33 AM  
Anonymous Stan Rawlinson said...

An Interesting and thought provoking article. I do not agree with all the summations. But many follow my studies and way of thinking.

As a Dog Behaviourist I certainly agree with many of the comments about the Alpha leader of the pack training regime. I believe it is absolute nonsense to suggest we can be the pack leader

I have also written an article called the The Alpha Myth and that can be seen here.

Keep up the good work.

7:50 AM  
Blogger Sue Beckhorn said...

Hi Darren,

I am a children's author contemplating a "first domesticated dog" story. Where do you think the story should be set? China? I'm thinking the wolf/dog that is first tamed from a pup to be a human companion might be one of these small, yellowish, extinct ancestor's that you and others mention. I need to know my setting so i can start researching flora and fauna, culture, etc.

Thanks for any help and advice, books to read, etc. you can give me.

Susan Williams Beckhorn
Author of Wind Rider
A novel about the "first" horse set in what is now Kazakhstan)

8:30 PM  
Blogger Maria S said...

Recently I finished my Certificate on Canine Nutririon and one of the topics we had to research was the origin of the domesticated dog because based on just that fact people justify what their dogs should or should not be eating. Raw feeders claim that dogs are straight descendants of wolves and therefore should share their diet. They say, dog's were not meant to eat grains because you never see wolves running through a field of corn, but they fail to recognize that in the wild when wolves kill their prey the first thing they go for is the "warm" contents of the stomach which is composed of fruits and grains, nothing else. I believe since dogs we're domesticated they have survived on cooked table scraps. Also our dogs do not share the same lifestyle as their counterparts, they don't have to travel miles for the next meal, they don't have to bear the inclement weather, etc.
I am glad that this topic is coming more and more to light and people are starting to understand that cooked table scraps are as good if not better than raw.

2:51 PM  
Anonymous Amrik Singh said...

Ifeel for sometime that the dogs ancestors must have been a wild dog/wolf mutch like the dingo . The grey wolf was a danger for stone age people more than today ,so many ,specialy children , would have been killed by wolves. As a recent event have proved again a tame gray wolf have a strong motivation to become alfa even if it does mean killing theyr human alfa to take its place . The dingo social behaviour have been observed and described by Brad Purcell in his book "DINGO" : The dingo live in small packs of four to six adults average, generaly only one pair breed . The agression toward stangers is more moderate, the strangers are more often chase away from the territory instead of killed if given a chanse as among the grey wolves.
As for hunting large isolate preys with dogs the way was for the dogs to keep the prey at bay by biting its rear to force it to fight instead of running(a wild boar or a dear for exemple)until the hunters arrive for the kill with theyr spears.

12:27 AM  
Blogger amrik singh said...

The australian dingo and other dogs like the carolina dog who live without human influence but only natural selection for many generations are particuliary interesting to understand dog ancestor behaviour . I know that many people like so much the romantic immage of "noble" large game hunter northern gray wolf that they will resist the idea that the smaller ancestor of the domestic dog was feeding mainly on rodens , other small preys and carrions with only few medium sise preys .

8:28 AM  

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