Ancient wolf genome reveals an early divergence of domestic dog ancestors

Dogs' special relationship to humans may go back 27,000 to 40,000 years, according to genomic analysis of an ancient Taimyr wolf bone. Earlier genome-based estimates have suggested that the ancestors of modern-day dogs diverged from wolves no more than 16,000 years ago, after the last Ice Age. Dogs' special relationship to humans may go back 27,000 to 40,000 years, according to genomic analysis of an ancient Taimyr wolf bone reported in the Cell Press journal Current Biology on May 21. Earlier genome-based estimates have suggested that the ancestors of modern-day dogs diverged from wolves no more than 16,000 years ago, after the last Ice Age.

The genome from this ancient specimen, which has been radiocarbon dated to 35,000 years ago, reveals that the Taimyr wolf represents the most recent common ancestor of modern wolves and dogs.

"Dogs may have been domesticated much earlier than is generally believed," says Love Dalén of the Swedish Museum of Natural History. "The only other explanation is that there was a major divergence between two wolf populations at that time, and one of these populations subsequently gave rise to all modern wolves." Dalén considers this second explanation less likely, since it would require that the second wolf population subsequently became extinct in the wild.

"It is [still] possible that a population of wolves remained relatively untamed but tracked human groups to a large degree, for a long time," adds first author of the study Pontus Skoglund of Harvard Medical School and the Broad Institute.

The researchers made these discoveries based on a small piece of bone picked up during an expedition to the Taimyr Peninsula in Siberia. Initially, they didn't realize the bone fragment came from a wolf at all; this was only determined using a genetic test back in the laboratory. But wolves are common on the Taimyr Peninsula, and the bone could have easily belonged to a modern-day wolf. On a hunch, the researchers decided to radiocarbon date the bone anyway. It was only then that they realized what they had: a 35,000-year-old bone from an ancient Taimyr wolf.

The DNA evidence also shows that modern-day Siberian Huskies and Greenland sled dogs share an unusually large number of genes with the ancient Taimyr wolf.

"The power of DNA can provide direct evidence that a Siberian Husky you see walking down the street shares ancestry with a wolf that roamed Northern Siberia 35,000 years ago," Skoglund says. To put that in perspective, "this wolf lived just a few thousand years after Neandertals disappeared from Europe and modern humans started populating Europe and Asia."

Citation

Skoglund et al. 2015. Ancient wolf genome reveals an early divergence of domestic dog ancestors and admixture into high-latitude breeds. Current Biology, 2015 DOI: 10.1016/j.cub.2015.04.019

The Goyet and Eliseevichi skulls were wolves not dogs, and a thought on the wolf-dog transition

The dates for dog domestication have been controversial. Some evidence (the Goyet cave fossils) pointed to the Pleistocene with the skulls suggesting dogs were transitioning from wolves to dogs, while other evidence suggested wolves transitioned to dogs when humans were hunter-gatherers, or during the Neolithic, when humans began living in more permanent settlements and engage in agriculture. Recently discovered Paleolithic fossil skulls, Goyet dated 31,680 +/− 250 YBP in the Czech Republic and Eliseevich 1 MAE (13,905 +/− 55 YBP) from the Bryansk Region in the central Russian Plain, were identified as dogs, establishing the date of dog domestication in the Paleolithic contemporaneous with human hunter-gatherers.

In a new paper Drake et al. (2015) use 3D geometric morphometric analyses to compare the cranial morphology of Goyet and Eliseevichi MAE to that of ancient and modern dogs and wolves. They find the Paleolithic canids are definitively wolves and not dogs. When compared to wolf-like breeds the skulls from Goyet and Eliseevichi MAE lack a cranial flexion and the dorsal surface of their muzzles do not have a concavity near the orbits. Morphologically, the fossils resemble wolves and no longer support the establishment of dog domestication in the Paleolithic.

The analysis in Drake et al. suggest previous measurement methodologies do not provide the resolution needed for distinguishing dogs from wolves and that 3D landmark-based geometric morphometric methods are better suited for the job. Geometric morphometric methods preserve size and shape information and allow for the inclusion of shape variation that cannot be gathered via calipers measurements.

Mitochondrial genomes revealed that Goyet, and other Paleolithic wolves, form the sister to all ancient and modern dogs. The Eliseevichi MAE, was not recovered in a clade with modern dogs but was genetically affiliated with modern wolves from Finland and Russia. The data from Drake et al is in accordance with the genetic evidence and they conclude that the Goyet and Eliseevichi MAE skulls lie within the wolf morphospace, together with the Paleolithic Alaskan wolves and Trou Balleux from Belgium. Drake et al. suggest a reassessment of the classification of the other fossil canids such as the Altai specimen (dated about 33,000 YBP) using 3D landmark-based geometric morphometric methods combined with genetic data, is needed to address the origin of domestication.

The Drake paper’s new classification of Goyet and Eliseevichi MAE as wolves, also suggests a reestablishment of the timing of dog domestication in the Neolithic. If shown to be correct it supports the Coppinger and Coppinger hypothesis that dog domestication occurred in the Neolithic when wolves began to scavenge near human settlements. Their hypothesis suggested human settlements provided a new niche because of the permanent supply of waste food and when combined with the Belyaev's experiment suggested wolf domestication could occur quickly. The establishment of permanent settlements in the Neolithic would have created an environment where sustained selection for tameness could exist for many generations thus setting the stage for dog domestication.

It seems unlikely this is the final word on the date of dog domestication and it simply shows that these skulls were wolves. But, they were wolves associated with archeological sites, not randomly found fossils. Thus the possibility that they were in some way associated with humans suggests there is more to the story. Pre-adaptive behaviors in wolves likely preceded domestication events. Yes, human settlements would have provided a continuous supply of garbage that could be scavenged. But prior to human settlements there was also a likely supply of wasted food that could have been exploited by wolves, paleo-dogs, and other scavengers – leftovers from megafauna kills. Large mammals killed during a hunt were unlikely to be completely consumed by the human hunters. 

Scavenging these large patches of waste nutrients would have brought humans and wolves into close contact – long before humans were living in Neolithic settlements. This scenario is more in line with the genetic results of Wang et al. (2013) suggesting parallel evolution between humans and dogs. The interesting part of this story is not necessarily the date when dogs and wolves diverged, but the events leading up to that date and the prior relationship between the dog’s ancestor and early humans. This was a relationship that likely changed the evolutionary trajectory of both the canine and the primate.

Citations

Drake AG,Coquerelle M, Colombeau G. 2015. 3D morphometric analysis of fossil canid skulls contradicts the suggested domestication of dogs during the late Paleolithic. Scientific Reports 2015/02/05/online. http://dx.doi.org/10.1038/srep08299

Wang GD, et al. (2013). The genomics of selection in dogs and the parallel evolution between dogs and humans. Nature communications, 4, 1860.

More on paleolithic hunters and dogs at Predmosti

Biogeologists have shown how Gravettian people shared their food 30,000 years ago. About 30,000 years ago Predmosti was inhabited by people of the pan-European Gravettian culture, who used the bones of more than 1000 mammoths to build their settlement and to ivory sculptures. Did prehistoric people collect this precious raw material from carcasses -- easy to spot on the big cold steppe -- or were they the direct result of hunting for food? Předmostí I is an exceptional prehistoric site located near Brno in the Czech Republic. Around 30,000 years ago it was inhabited by people of the pan-European Gravettian culture, who used the bones of more than 1000 mammoths to build their settlement and to ivory sculptures. Did prehistoric people collect this precious raw material from carcasses -- easy to spot on the big cold steppe -- or were they the direct result of hunting for food? This year-round settlement also yielded a large number of canids remains, some of them with characteristics of Palaeolithic dogs. Were these animals used to help hunt mammoths?

To answer these two questions, Tübingen researcher Hervé Bocherens and his international team carried out an analysis of carbon and nitrogen stable isotopes in human and animal fossil bones from the site. Working with researchers from Brno and Brussels, the researchers were able to test whether the Gravettian people of Předmostí ate mammoth meat and how the "palaeolithic dogs" fit into this subsistence picture.

They found that humans did consume mammoth -- and in large quantities. Other carnivores, such as brown bears, wolves and wolverines, also had access to mammoth meat, indicating the high availability of fresh mammoth carcasses, most likely left behind by human hunters. Surprisingly, the dogs did not show a high level of mammoth consumption, but rather consumed essentially reindeer meat that was not the staple food of their owners. A similar situation is observed in traditional populations from northern regions, who often feed their dogs with the food that they do not like. These results also suggest that these early dogs were restrained, and were probably used as transportation helpers.

These new results provide clear evidence that mammoth was a key component of prehistoric life in Europe 30,000 years ago, and that dogs were already there to help.

Citation

Bocherens H, Drucker DG, Germonpré M, Lázničková-Galetová M, Naito YI, Wissing C, JBrůžek J, Oliva M. 2014. Reconstruction of the Gravettian food-web at Předmostí I using multi-isotopic tracking (13C, 15N, 34S) of bone collagen. Quaternary International, 2014; DOI:10.1016/j.quaint.2014.09.044

Thoughts on the origin of dogs. 1.

1.    

Jean-Baptist Lamarck seems to be the first scientist to suggest dogs were descended from wolves. In his 1809 Zoological Philosophy he wrote, “No doubt a single, original race, closely resembling the wolf if indeed it was not actually the wolf, was at some period reduced by man to domestication.”

Dog ancestry has been debated ever since Lamarck’s comments and a variety of hypotheses have been proposed and tested in various ways.

Olsen (1985) suggested hominids and wolves have had a relationship that started sometime between 500,000 and 200,000 YPB. He wrote,

“One of the earliest known associations of Canis lupus with hominids (Homo erectus pekinensis) is from the fossil site at Zhoukoudian, located about 42 kilometers southwest of Beijing… Although this association of hominids and wolves at this early period does not imply in any way either taming or early domestication it does place both genera of animals in contemporary association that apparently continued until such time that these events did occur.”

In fact evidence of hominids and canids living in proximity dates to 810,000-760,000 YBP in Spain (Garcia and Arsuaga, 1999); and to about 521,000 YBP at Boxgrove, England. Garcia and Arsuage consider the Boxgrove canid to be Canis mosbachensis. Thus, Olsen’s comment is further supported – the two genera, Canis and Homo have a long relationship, even if it was only sharing the same landscape as competitors – they were part of the same fauna and destined to interact. Keep in mind that members of a fauna adapt to each other, the adaptations may be obvious or subtle.

Stories of dog domestication are numerous, each with their own twists and wrinkles added by the authors, for now I will summarize the domestication event stories by saying. Humans picked up wolf cubs raised them and the wolves adopted their human family. Wolves were selected for tameness and they quickly morphed over generations into the ancestor of the domestic dog of today.

This has become a “just so story” that is relatively well accepted in the minds of the general public and probably most people who study dogs. Just so stories are dangerous because they become dogma until they are replaced with an alternative story based upon a changing paradigm as more contrary evidence accumulates to suggest an alternative scenario.

Most of the popular literature and scientific work affirm Lamarck’s proposal, the grey wolf (Canis lupus) is the ancestor of the domestic dog. Evidence for a close relationship between grey wolves and dogs is quite substantial using morphology, genetics, and the fact that dogs and wolves hybridize. Below is a phylogeny for canids from Linblad et al. (2005), they used a  

“…a high-quality draft genome sequence of the domestic dog (Canis familiaris), together with a dense map of single nucleotide polymorphisms (SNPs) across breeds. The dog is of particular interest because it provides important evolutionary information and because existing breeds show great phenotypic diversity for morphological, physiological and behavioural traits….”

There are a large number of phylogenies in the literature and most of them show a similar arrangement when it comes to dogs and the grey wolf. The arrangement is as sister species – not ancestor-descendant. A general principle of cladistics suggests that when one species separates into two, the ancestral species “dies,” meaning it no longer exists. In its place are the two sister species. Following this idea, Canis lupus and Canis familaris are sister species not ancestor and decedent.  The sister species relationship is supported in numerous studies and should not be controversial.

However, only extant species are represented in the tree. There are likely several to many extinct members of the genus Canis not in the tree because their DNA is not available. If they could be added, the tree would have a different topography. As more fossil Canis are found it is likely ancient DNA will be extracted from them and added to the tree. When this occurs the sister relationship between C. lupus and C. familaris is likely to change.

Our knowledge of canids is still incomplete. Leonard and colleagues (2007) examined remains of 56 ancient wolves from the permafrost near Fairbanks, Alaska and found a continuous population from 12,500 YBP to beyond the capacity of radiocarbon (about 58,000 years) to resolve a date for them. Only a single wolf was dated after the 12,500 year mark, at 7,647 YBP. The older wolf remains showed wider palates with larger carnassial teeth suggesting they had a greater bite force. Their teeth also showed greater degrees of wear suggesting that they were specialized for killing and consuming large prey or habitually scavenging on exceptionally large prey – the megafauna. Leonard and colleagues obtained ancient DNA from 20 of these wolves from the late Pleistocene of eastern Beringia and recovered a haplotype that was not shared with any existing wolf population. The Pleistocene gray wolf was quiet distinct from the modern gray wolf. However, three wolves from the Ukraine and one from Altia (Russia) dated between 30,000 and 28,000 YBP shared the same haplotype as the Fairbanks remains  ―suggesting the Pleistocene Gray Wolf was widely distributed in the Northern Hemisphere from at least 50,000 YBP to about 12,500 YBP. These wolves lived north of the ice sheets. A nitrogen isotope analysis of the bones showed the Pleistocene Gray Wolf preyed and scavenged on mammoth, bison, musk ox and caribou.

The lack of overlap between modern wolves and the Pleistocene wolves is striking and suggests the ancient wolves became extinct and were not ancestral to the modern wolf. As the megafauna herbivores disappeared so did their predators, the Pleistocene Gray Wolf was one of them.

While I don’t claim to have the ultimate answer to dog origins the following seem likely and obvious:

      1) Dogs shared an ancestor with a wolf – but not the extant gray wolf.
2) Dogs are primarily scavengers, but they can act as predators.
3) The social structure found in dogs is not as rigid as that found in extant gray wolves.
4) Dogs and wolves do hybridize, but wolves often show aggression towards domestic dogs, reducing the likelihood of hybridization under natural conditions.
5) The geographic point of origin is likely somewhere in Eurasia as opposed to Africa or North America – but African Canis familaris do show substantial genetic diversity
6) The dog or its ancestor was pre-adapted for interacting with humans.
7)  Humans (and in the broad sense, hominins) have a long history of interacting with dogs (and probably their ancestor), thus dog-human interactions, and dogs as a species predate agriculture.

References

Freedman AH, Gronau I, Schweizer RM, Ortega-Del Vecchyo D, Han E, et al. (2014) Genome Sequencing Highlights the Dynamic Early History of Dogs. PLoS Genetics 10(1): e1004016. doi:10.1371/journal.pgen.1004016

Garcı́a, N., & Arsuaga, J. L. (1999). Carnivores from the Early Pleistocene hominid-bearing Trinchera Dolina 6 (Sierra de Atapuerca, Spain). Journal of Human Evolution, 37(3), 415-430.

Lamarck, JB 1809. Zoological Philosophy: An Exposition with Regard to the Natural History of Animals, vol. 1, Dentu, Paris, France.

Leonard, J. A. C. Vilia, K. Fox-Dobbs, P. L. Koch, R. K. Wayne, and B. V. Valkenburgh. 2007. Megafaunal extinctions and the disappearance of a specialized wolf ecomorph. Current Biology 17:1146-1150.

Lindblad-Toh, K., et al.  2005. Genome sequence, comparative analysis and haplotype structure of the domestic dog." Nature 438.7069: 803-819.

Olsen, SJ. 1985. The Origins of the Domestic Dog, the Fossil Record. University of Arizona Press.

Ancestry informative markers in wolves and dogs demonstrate hybridization events

Figure 1 from Godinho et al. (2014) (a) Wolf–dog hybrid from 

Barbanza. Photo courtesy of A. Perez. (b) Location of wolf 

reference samples. Approximate wolf distribution area is 

showen in dark grey (Alvares et al. 2005). The red arrow 
shows the location of Barbanza. (c) Distribution of wolf packs 

(100-km2 circles) in Barbanza (red circle) and the surrounding 

area (black circles) between 1999 and 2003. Dots denote the

location of NIS.

Across the globe, millions of free-ranging dogs coexist with a few tens of thousands of wolves. Wolf-dog hybridization provide a classic example of the ecological and conservation implications of hybridization events between wild and domesticated forms. However the ability to understanding the implications of hybridization has been hampered by high genetic similarity and the difficulties in obtaining tissue samples. Consequently, there are many opportunities for wolves and dogs to hybridize, and cumulative data suggest that hybridization may be more frequent than previously suspected. Previous hybridization studies have required the slow and expensive use of tissue samples collected from dead or trapped animals, thus limiting population-level assessments. Furthermore, difficulties have been reported in correctly identifying wolf–dog backcrosses using simulated individuals and sets of 16–18 microsatellites, typically resulting in a large threshold implemented in clustering analyses.

In a forthcoming article Godinho et al. (2014) assess the occurrence and extension of hybridization in a pack of wolf–dog hybrids in northwestern Iberia, Godinho et al. compare the power of 52 nuclear markers implemented on tissue samples with a subset of 13 ancestry informative markers (AIMs) typed in noninvasive samples (NIS).

Godinho et al. (2014) find the 13 AIMs are as accurate as the 52 markers that were chosen without regard to the power to differentiate between wolves and dogs. The AIMs also having the advantage of being rapidly screened on noninvasive samples. The efficiency of AIMs significantly outperformed ten random sets of similar size and an additional commercial set of 18 markers.

Bayesian clustering analysis implemented on AIMs and NIS identified nine hybrids, two wolves and two dogs. Four hybrids were unambiguously assigned to F¹ x Wolf backcrosses. The new approach (AIMs + NIS) overcomes previous difficulties related to sample availability and informative power of markers, allowing a quick identification of wolf–dog hybrids in the first phases of hybridization episodes. This provides managers with a reliable tool to evaluate hybridization and estimate the success of their actions. This approach may be easily adapted for other pairs of wild/domesticated species, thus improving our understanding of the introgression of domestication genes into natural populations.

The hybridization event at Barbanza started with a cross between a female wolf and a male dog, as inferred by the presence of an Iberian wolf mtDNA haplotype in all hybrids, corresponding to the typical direction of wolf–dog hybridization. Despite the uncertainty of the impact of these crosses in the genetic composition of wolf populations (for example, due to difficulties of hybrid integration in packs), the results do suggest that the Barbanza pack has quickly evolved towards a hybrid swarm, with a minimum of two generations of backcrossing to wolves. These findings are alarming because wolf packs in nonexpanding populations generally consist of related individuals, and thus, other unobserved individuals in the area may also exhibit admixed ancestries.

Identifying wolf–dog hybrids is crucial for conservation and management strategies, particularly in the first phases of an episode of hybridization, as well as to evaluate the success of the strategies that have been implemented. Assuming a minimum territory size of 100 km² centered in the rendezvous site of the Barbanza pack, the area sampled covered a substantial portion of that territory (40%).

Moreover, the authors identified 11 wolf-like canids, 80% of the estimated population, which is fully compatible with the values reported in Iberia for pack size after reproduction, plus some floater animals, suggesting that the AIM’s method allows a comprehensive evaluation of hybridization in a given area. The goal to obtain a quick method to identify hybridization events was successful. Once there is the suspicion of a hybridization event, an estimate of about two months would be required to know the extent of the problem in an area equivalent to a pack territory.

Finally, the authors note that the logistic and economic investment to evaluate hybridization in this area was feasible (ca. 1500€ for the fieldwork – one person working 8 days – plus ca. 5000€ for laboratory work – one person working 3 weeks). Current management guidelines state that every practical measure should be implemented to remove obvious hybrids from the wild once an event of hybridization has been detected. This implies mainly lethal control, although keeping hybrids in captivity and sterilization have also been suggested. Nevertheless, the efficiency of removing hybrids from the wild remains very uncertain. Therefore, the methods shown here constitute a step forward towards the effective management of wolf–dog hybridization. The combination of NIS and AIMs may offer an opportunity to better understand the extension and persistence of hybridization between wolves and dogs at a global scale and its ecological, evolutionary and conservation consequences.

Citation

Godinho, R., López‐Bao, J. V., Castro, D., Llaneza, L., Lopes, S., Silva, P., & Ferrand, N. (2014). Real‐time assessment of hybridization between wolves and dogs: combining noninvasive samples with ancestry informative markers. Molecular Ecology Resources. Early On-line.

Paleodogs and the date of domestication

Top. A fox skull used to illustrated greatest patatal breadth 

and condylobasal length. Bottom. A bivariate plot from 

Morey (2014) of GPB (Greatest Palatal Breadth) by CL 

(Condylobasal Length) for three groups of modern or 

Holocene wolves, and one series of established prehistoric

dogs, post-dating 10,000 BP, from North America and Europe.

 The contours indicate the range of plotted scores for each 

group. Superimposed on this plot are the corresponding values 

for several putative Paleolithic dogs. Using CL as a guide, one 

can see that the putative Paleolithic dogs are wolf-sized, but 

have unusually broad palatal dimensions. A comparable plot is 

provided by Boudadi-Maligne and Escarguel (2014: 86, Fig. 5),

 based on the same variables and using a larger series of wolves. 

That plot includes the earliest of the putative Paleolithic dogs

 considered here (Goyet Cave, Razboinichya Cave, Predmostí), 

and shows the same basic result.

In a forth coming article Morey (2014) examines the evidence for paleodogs, dogs that are older than the fossil record has traditionally supported.

Archaeological evidence has, for a very long time placed the origin of the domestic dog between 15,000 to 12,000 YBP. But, recent works report fossil evidence suggesting a much earlier origin, dating to Paleolithic times and perhaps exceeding 100,000 years. With such studies as a backdrop, scenarios for more ancient dates for dog origins and domestication have been made and they exceed 30,000 YPB. Morey examines this evidence and suggests such studies exhibit conceptual and methodological flaws.

When a series of cases for putative Paleolithic dogs is assessed, the author finds convincing cases for such dogs are confined to about the past 15,000 years. Morey looks at the timing of reproduction and skull and tooth morphometrics and with two exceptions, finds the putative Paleolithic dogs fall within the range of established wolves. See the figure for an explanation. Thus, the morphometrics do not support the assessment of these canids as dogs.

He also discusses the age at first reproduction of wolves and dogs, noting it may have been almost two years for wild wolves; and noting captive wolves may breed much sooner. The point being that even first reproduction at two years old, the generational time translates into dozens of generations over a mere few hundred years. Combined with directional selection, the wolf/dog would change its morphology substantially in a very short time. So genetic isolation was likely not in place at first, resulting in some delay in the recognizable appearance of certain domestication traits. But, genetic isolation was never complete, since dogs and wolves continue to hybridize to a limited degree to the present day. Therefore, he concludes that allowing for modest delay in the appearance of domestication changes, 16,000-17,000 YBP is a reasonable estimate for the beginnings of sustained canid domestication.

The morphometric evidence is somewhat at odds with the genetic data. One study done in 1997 suggests dogs diverged from wolves somewhere between 100,000 to 30,000 YPB. A more recent (2013) study using mitochondrial genomes estimates 33,000 to 18,000 YBP, and a yet more recent study (2014) places the divergence date of wolves and dogs between 50,000 and 11,000, although the authors, suggest that a more recent date is probable.

Resolving the differences in the molecular studies with the morphometrics promises to be challenging and as several recent authors have suggested, the domestication of the dog is much more complex than previously imagined.

Citation

Morey, D. F. (2014). In Search of Paleolithic Dogs: A Quest with Mixed Results. Journal of Archaeological Science. 52:300-307.

Optimism Index in Dogs

Photo Credit: © B.Stefanov / Fotolia

Dogs generally seem to be cheerful, happy-go-lucky characters, so you might expect that most would have an optimistic outlook on life.

In fact some dogs are distinctly more pessimistic than others, research from the University of Sydney shows.

"This research is exciting because it measures positive and negative emotional states in dogs objectively and non-invasively. It offers researchers and dog owners an insight into the outlook of dogs and how that changes," said Dr Melissa Starling, from the Faculty of Veterinary Science. Her PhD research findings are published in PLOS One today.

"Finding out as accurately as possible whether a particular dog is optimistic or pessimistic is particularly helpful in the context of working and service dogs and has important implications for animal welfare."

Dogs were taught to associate two different sounds (two octaves apart) with whether they would get the preferred reward of milk or instead get the same amount of water. Once the dogs have learnt the discrimination task, they are presented with 'ambiguous' tones.

If dogs respond after ambiguous tones, it shows that they expect good things will happen to them, and they are called optimistic. They can show how optimistic they are by which tones they respond to. A very optimistic dog may even respond to tones that sound more like those played before water is offered.

"Of the dogs we tested we found more were optimistic than pessimistic but it is too early to say if that is true of the general dog population," said Dr Starling.

However it does mean that both individuals and institutions (kennels, dog minders) can have a much more accurate insight into the emotional make-up of their dogs.

According to the research a dog with an optimistic personality expects more good things to happen, and less bad things. She will take risks and gain access to rewards. She is a dog that picks herself up when things don't go her way, and tries again. Minor setbacks don't bother her.

If your dog has a pessimistic personality, he expects less good things to happen and more bad things. This may make him cautious and risk averse. He may readily give up when things don't go his way, because minor setbacks distress him. He may not be unhappy per se, but he is likely to be most content with the status quo and need some encouragement to try new things.

"Pessimistic dogs appeared to be much more stressed by failing a task than optimistic dogs. They would whine and pace and avoid repeating the task while the optimistic dogs would appear unfazed and continue," said Dr Starling.

"This research could help working dog trainers select dogs best suited to working roles. If we knew how optimistic or pessimistic the best candidates for a working role are, we could test dogs' optimism early and identify good candidates for training for that role. A pessimistic dog that avoids risks would be better as a guide dog while an optimistic, persistent dog would be more suited to detecting drugs or explosives."

Dr Starling has been working with Assistance Dogs Australia, a charity organisation that provides service and companion dogs to people with disabilities, to investigate whether an optimism measure could aid in selecting suitable candidates for training.

The research not only suggests how personality may affect the way dogs see the world and how they behave but how positive or negative their current mood is.

"This research has the potential to completely remodel how animal welfare is assessed. If we know how optimistic or pessimistic an animal usually is, it's possible to track changes in that optimism that will indicate when it is in a more positive or negative emotional state than usual," said Dr Starling.
"The remarkable power of this is the opportunity to essentially ask a dog 'How are you feeling?' and get an answer. It could be used to monitor their welfare in any environment, to assess how effective enrichment activities might be in

Citation
Starling MJ,  Branson N, Cody D, Starling TR, McGreevy PD. 2014. Canine Sense and Sensibility: Tipping Points and Response Latency Variability as an Optimism Index in a Canine Judgement Bias Assessment. PLoS ONE, 2014; 9 (9): e107794 DOI: 10.1371/journal.pone.0107794

Dogs are the dominat prey of Indian Leopards

Photo credit: WCS India

A new study led by the Wildlife Conservation Society reveals that in India's human dominated agricultural landscapes, where leopards prowl at night, it's not livestock that's primarily on the menu -- it is man's best friend.

The study, which looked at scat samples for leopards in India's Ahmednagar's district in Maharashtra, found that 87 percent of their diet was made up of domestic animals. Domestic dog dominated as the most common prey item at 39 percent and domestic cats were second at 15 percent.

Seventeen percent of the leopard's diet consisted of assorted wild animals including rodents, monkeys, and mongoose, and birds.

Livestock, despite being more abundant, made up a relatively small portion of the leopard's diet. Domestic goats, for example, are seven times more common than dogs in this landscape, yet only make up 11 percent of leopard's prey. The author's say this is because goats are less accessible and often brought into pens at night, while dogs are largely allowed to wander freely. Cows, sheep, and pigs were also eaten, but collectively made up less than 20 percent of leopard's food. Most domestic cattle in this region are too large to be preyed on by leopards.

The authors of the study say that the selection of domestic dogs as prey means that the economic impact of predation by leopards on valuable livestock is lower than expected. Thus, human-leopard "conflict" is more likely to be related to people's fears of leopards foraging in the proximity of their houses and the sentimental value of dogs as pets.

Study co-author Ullas Karanth, WCS Director for Science-Asia, said: "During the past two-to-three decades, legal regulation of leopard hunting, increased conservation awareness, and the rising numbers of feral dogs as prey have all led to an increase in leopard numbers outside of nature reserves in agricultural landscapes. While this is good news for conservation and a tribute to the social tolerance of Indian people, it also poses major challenges of managing conflict that occasionally breaks out. Only sound science can help us face this challenge."

Citation

Vidya Athreya, Morten Odden, John D. C. Linnell, Jagdish Krishnaswamy, K. Ullas Karanth. A cat among the dogs: leopard Panthera pardus diet in a human-dominated landscape in western Maharashtra, India. Oryx, 2014; 1 DOI: 10.1017/S0030605314000106

Dogs in the prehistory of Western Europe based on archaeozoological evidence

The representations of prehistoric dogs are very rare.

 In this example from the Neolithic site of Catal Hüyük

 in the Near Orient (7000 BC), a dog seems to be 

assisting the hunt (from Benecke N. 1994, Der Mensch 

und seine Haustiere. Die Geschichte einer 

jahrtausendalten Beziehung. Thesis).

In a new paper, Horard-Herbin, Tresset, and Vigne examine the history of the dog in Western Europe through archaeozoology evidence, and make inferences about the relationships between humans and dogs through prehistory. The dog was domesticated by Upper Paleolithic hunter-gatherers, but the domestication process remains unclear, in terms of chronology, geographic origin, and recurrence of the phenomenon. What follows is my summary of the paper, representing the author’s view on the history of dogs in Europe. The entire paper is available on-line.

The first dogs appeared in the Late Glacial between 18,000 and 10,000 BC, from the Magdalenian period to the end of the Epipalaeolithic. Evidence for morphologically transformed animals come from the Iberian Peninsula, Siberia, Aquitaine in France, the French Alps, central and northern Europe, and the Near East. In the authors’ view multiple independent domestication events took place across much of the Old World. Recent morphometric analyses of dogs from the southeast and north of France have revealed marked morphological differences between a group of small-sized dogs originating in the West and other much larger dogs with a different physical structure from northeast Europe in the same period; indeed, some of these “larger dogs” were probably wolves. This study led to formally identifying two very distinct populations of dogs during the Upper Paleolithic, which potentially reflect distinct centers of domestication. These findings support the fragmentation in the landscape in the Late Glacial of Eurasia due to the polar and orogenic ice caps, and also the diversity and relative isolation of hunter-gather cultures from the same period. This is also in line with the common practice in hunter-gatherer societies of pet keeping, where young animals were integrated in the family group and breast fed with the children to compensate for the animals taken from nature through hunting. This practice, demonstrating that hunter-gatherers were as capable of raising animals as the Neolithic age people, could have played an important role in the domestication of dogs in different places.

 Late Glacial dogs displayed a wide variety of statures, from medium-sized Natoufian dogs in the Near East and their Northern Zagos contemporaries (height: 45 to 60 cm), to medium or large sizes (height > 60 cm) for dogs in eastern Europe, to very small dogs (height 30 to 45 cm or < 30 cm) in Germany, Switzerland, the east of France, and the southwest and north of Spain. Other large canid fossils dated about 30,000 BC found in Belgium, Siberia (27,000 BC), and the Czech Republic (24,000 BC) have been interpreted as domestic dogs 15,000 years before the others. However, analyses suggest that the morphological character considered by the authors of these discoveries as identifying domestication are instead morphological variations of the Upper Paleolithic wolves, whose morphological variability remains poorly known.

Dogs were scarce in the early Neolithic of Europe, with the notable exception of the Herxheim pit enclosure (western Germany, Linearbandkeramik culture, end of the sixth millennium cal. BP), where dogs were found in partial association with human remains. The few data collected for this period suggest the animals remained relatively large, though significantly smaller than the wolf. Modifications such as shortening of the face and dental crowding were also already obvious in animals of this period. Tooth anomalies (essentially missing teeth) were frequent. The decrease in size was accentuated until the fourth millennium cal. BP and culminated in the Neolithic/Chalcolithic period with the occurrence of small and very small dogs in southeastern Europe but also in western Europe (at Bercy and many other sites of the Chasséen complex and related cultures). These small dogs are rarely found complete and are often retrieved from rubbish pits and dumping areas, which strongly suggests that they were commonly consumed, even when cut or burn marks are absent. Estimation of age based on tooth eruption and tooth wear shows that young and subadult animals were the most abundant, strengthening the hypothesis that dogs were consumed in this period.

Few dogs found at the end of the Neolithic in Western Europe were larger than those evidenced for the fourth millennium. The incomplete dogs found in a mass grave at Bury in northern France were large individuals with slightly shortened faces. Analyses of their DNA showed that one of them at least was black, whereas another still retained the wild coat color. Overall, data from the Mesolithic and Neolithic periods in Europe provide evidence about the evolution of dog phenotypes and the status of dogs.

Bronze Age dogs are rare, but those studied from central and Eastern Europe, the British Isles, and the Italian and Iberian peninsulas are generally of a homogeneous size. 40 to 50 cm with occasionally a few larger individuals, but never smaller specimens. The only region for which this is not true is Switzerland where the size of dogs also increased significantly from the late Neolithic, but where in the late Bronze Age, a population of larger, sturdier dogs remained (50 to 60 cm).

During the Iron Age, the majority of the canine population remained morphologically homogeneous, with dogs averaging 40 to 55 cm in the British Isles, Gaul, central Europe, and Italy. They were slender animals whose leg bones presented no particular modifications, such as twisting or marked sturdiness, which characterized certain morphotypes from the Roman period. Nevertheless, at the end of the Gallic period, an increase in size at the withers could be observed with the appearance of small and large dogs. Taking the example of Gaul, the first phenomenon during the second century BP was the appearance of small dogs in certain habitats only, namely those of aristocrats, and in certain sanctuaries. These small individuals were isolated and always associated with a medium-sized population from which they seemed not to have originated. According to the current state of knowledge, only three sites of Celtic Europe show a bipartite distribution of wither heights, a large number of individuals, and all the intermediate sizes: Levroux (Indre, France) and Manching and Berching-Pollanten, both in the same region of Bavaria. On the site of Levroux, some skulls show a marked shortening of the face associated with dental pathologies. Indeed, some teeth are missing or overlapping, which is firm evidence of face shortening, but there is no sign of limb bone modification. The highlighting of these specific breeding places is an interesting observation in regards to the ancient authors who indicated that specialized dog breeding existed in Gaul and Great Britain, mainly for hunting or war dogs.

At the end of La Tène period on a few European Celtic sites, very small dogs appeared that qualify as dwarfs. They were extremely rare, isolated among populations from which they could not have stemmed, and their sizes being outside all the size ranges known in the Iron Age. This is the case for the only complete skeleton of a dog measuring 27 cm at the withers from the Oppidum of Rheinau, Switzerland, and whose presence has been interpreted as an import of a pet from the Mediterranean region. This hypothesis is in line with those developed by several authors suggesting that these dwarf lapdogs, much appreciated by Roman ladies, originated in the Roman Empire. They would have been offered to the upper classes of the Celtic society by the Romans, in the same way as observed for horses, and attested to by certain ancient authors. Included with luxurious gifts, they would have had an exceptional value and status.

The limitation of this import hypothesis is that on examining the range of wither heights of dogs in Italy from the Neolithic to the end of the Roman period or dogs from Pompeii, no dwarf dogs less than 29 cm can be observed during what is known as the Early Roman period (third century BC to second AD corresponding to our chronology of the Iron Age and the Early Roman period), and those smaller than 25 cm only appeared at the end of the Roman Empire (third to sixth century AD;). On the other hand, dwarf dogs (20, 22, and 23 cm) have been found in Germany, Hungary, France, and Great Britain from early Roman times. For the latter, observed that these dogs were smaller than their contemporaries in Italy. This is clear evidence that the hypothesis of dwarf Roman dogs being imported is not pertinent for the Iron Age, and the function, origin, and means of circulation of dwarf dogs at the Celtic European scale remain unknown.

During the second Iron Age, large dogs reaching a maximum wither height of 65 cm were found in Europe, corresponding approximately to the size of a Gordon Setter, but which had still not reached the 75 cm height of a very large dog (taller than a wolf), which did not appear until the Roman period. These large dogs were found in Belgium and Germany and very rarely in Gallic settlements with less than 10 individuals measuring more than 60 cm. It is difficult to determine whether these dogs represent the upper limit of the size range of middle-sized populations, stemmed from slightly larger populations persisting in certain regions (in Austria, on the Durezza cave site, the size range of dogs from the first Iron Age was from 49 to 64 cm; n = 126), or were the result of specific breeding that has not been identified through archaeology yet, such as war dogs mentioned by ancient authors. In general, studies investigate samples that are too small to enable definition of a population, and only with the development of genetic studies will light be shed on this question.

In any case, the very small and very large individuals are extremely rare, and it is complex to determine whether their morphotypes, identified as specific through our archeozoological analyses, are in fact linked to a specific status. It has been established that some individuals were incinerated with their “master” in a funeral context, while others were simply eaten, and the fate of some of them did not differ fundamentally from that of medium-sized dogs, as explained below.

The Celts lived with a pack of dogs of similar morphology. However, from the skeletal evidence available, it is clear this was the beginning of selection of certain morphotypes, as illustrated by the shortening of the face of certain skulls and the associated pathologies, and the diversification of wither height. This is reflected in the 30 or so “races” of dogs cited by ancient authors and for which iconographic representations have remained. In the texts, they are characterized by their geographic origins and by the services they provided: pet, hunting dog, war or guard dog, some coming from Gaul such as the Vertagus or the Ségusien hound.

The authors conclude that a general and partial approach to the evolution of dogs in Europe from the Paleolithic to the Iron Age shows to what extent certain questions regarding this species reoccur across time. In particular, at the beginning of the Neolithic and at the end of the Iron Age, indigenous lines and exogenous inputs can be observed. It would be interesting to characterize these new dogs from the point of view of their bone morphology (e.g., size, robustness, and proportions) and their genetic characteristics (e.g., origins and coat color) to measure their impact on the population in place over the long term (e.g., cohabitation, replacement). These elements are also necessary to draw a link between specific morphotypes and functions as certain modern-day societies (e.g., South Korea) have races of dogs for meat production, even though the term race is completely inappropriate for the periods of interest. (The term race refers to a population of the same species having distinct hereditary, morphological, and physiological characteristics according to the standards defined in the herd and flock books drawn up since the 19th century. For all earlier periods, the more appropriate term morphotype should be used.)

Citation

Horard-Herbin M-P. Tresset A, Vigne D-D. 2014. Domestication and uses of the dog in western Europe from the Paleolithic to the Iron Age. Animal Frontiers 4 (3): 23-31.

Hokkaido Island dogs and human diets 1500 YBP

Hokkaido Island dog today

One of the disadvantages of keeping dogs is their requirement for a high protein diet, placing them in competition with humans. On the other hand if dogs and humans are eating the same things it would suggest a reason for them to come together when food was plentiful. Feeding dogs would give the dogs a reason to follow hunters, and cooperate with humans.

In a forthcoming paper Tsutaya et al. (in press 2014) analyze carbon and nitrogen isotopes from human and dog remains from the Moyore site on eastern Hokkaido Island, Japan. The Moyoro archeological site is located on an estuarine sand area of the Abashiri River and is representative of the shell mounds of the Okhotsk culture. The site has been excavated several times during the 20th century and contains human burials and the remains of pit dwellings. Radiocarbon and palaeomagnetic dating suggest the site was used 1500 YBP.

The isotopic data shows the dogs were predominantly feeding on brackish-water fish, marine fish, and marine mammals (5-45%). The presence of marine mammals in the dog’s diet suggests that humans were feeding the dogs.

The δ13C and δ15N values of adult human bone collagen found terrestrial food sources provided less than 16% of the diet and that the Moyoro human population depended heavily on marine mammals for dietary protein. Marine mammals made up 80-90% of the Moyoro human diet. Thus, there was no significant overlap in the diet of the dog and the human population.

Ethnographic studies of the late 19th and early 20th century reported on dog use and dog diet of the indigenous Ainu people in Hokkaido and Sakhalin, and fishers in Kamchatka. Ethnographic accounts of the Ainu population in Hokkaido and Sakhalin reported dogs were used for hunting terrestrial mammals and sledging. Dog skins were used to make clothes and shoes. The Ainu people fed their dogs with low-sodium trout and the isotope ratio of trout in Hokkaido is similar to that of brackish-water fish. Fishers in Kamchatka in the late nineteenth century fed their domesticated dogs with dried or fermented fish and used them to pull sledges. Although the cultural traits reported in modern ethnographic studies are not directly comparable with those in the ancient Okhotsk population, such ethnographic observations agree well with the isotopic results in the Tsutaya et al. (2014) study.

Citation

Tsutaya T, Naito YI, Ishida H, and Yoneda M. (in press 2014). Carbon and nitrogen isotope analyses of human and dog diet in the Okhotsk culture: perspectives from the Moyoro site, Japan. Anthropological Science. 

Dogs and herders in southern Africa

Photo Credit: Johan Gallant

The geographical origin for the domestic dog is probably Eurasia. While modern dogs may have had a single origin about 15,000 YBP, earlier paleodogs may have been present 33,000 YBP. Dogs in sub-Sahara Africa therefore are most likely to be recent invaders from Eurasia. Currently, the oldest archaeological evidence for the presence of domestic dogs in Africa comes from about 7000-6000 YBP (the Neolithic of Egypt’s Western Desert and along the Nile in Egypt and Sudan). However, dogs do not appear to be widespread or common in African archeological sites until about 1000 YBP. This may be the result of confusion distinguishing between dog remains and jackal remains, or a more recent introduction of dogs.

In a new paper, Peter Mitchell (2014) of Oxford University follows up on an earlier paper on dog use by pre-colonial herders in southern Africa. Mitchell notes that dogs were one of several domestic animals kept by south African herders, but their economic and social relevance is poorly known. He reviews the evidence for the dog’s introduction into southern Africa and assesses the relative strengths of various lines of evidence (osteology; ancient DNA; animal tracks; faunal taphonomy) to identify those instances where the presence of dogs can most convincingly be established on sites used by herders.

The study reports skeletal evidence for herder-associated dogs comes from a handful of sites in the western half of South Africa, Namibia and, possibly, Botswana. A review of previous studies noted the strongest evidence is a nearly complete human burial in a shell midden at Cape St Francis on the Indian Ocean coast (dated 1150 ± 40 YBP) found with the skeleton of a small dog in the lap of the human skeleton. Other evidence suggests dogs have been present in the western regions of southern Africa since about at about the same time. Mitchell suggests that herder communities in the Cape acquired dogs through some exchange-mediated process of diffusion sourced ultimately to farmers in the eastern third of South Africa.

The first documented observation of dogs in southern Africa was made by Vasco da Gama and dates to 7 November 1497 when the Portuguese explorer observed people who were probably hunter-gatherers with dogs. Most observations of dogs with Khoe-speaking herders postdate the onset of Dutch colonization of the Cape in 1652. The dogs were medium height with short hair, long muzzles, and ears that could be erect and pointed or drooping. Analysis of skeletons buried at Zerrissene Mountain and Cape St Francis supports this description. These dogs were small, and more gracile overall than those found at agro-pastoralist sites in the Shashe-Limpopo Basin.

Some commentators suggest that the Khoe-speakers did not value their dogs highly, noting they were few in number and scrawny, and not cared for. But, in 1731 Peter Kolbe wrote more extensively about these people and considered the dogs well taken care of. Dogs of the Korana speaking people were larger and varied from grey to white to brown in color, but interbreeding with dogs introduced to South Africa by Europeans cannot, perhaps, be excluded. Korana dogs were also well treated. They were feed meat and milk.

Mitchell proposes dogs in used by herding cultures acted as companions, guard dogs, defenders of livestock, and as aids in hunting. While the Damara in north-central Namibia apparently ate dogs, there is no evidence to support this in the other cultures. Dogs also played a role in the belief systems of these peoples, to at least a limited degree.

Hendrik Wikar led an expedition to the north of the Cape Colony in the 1770s, and recounts the story of a group of women who chose to sleep on an elephant trail close to a river. Not having dogs with them, and having chosen not to light a fire, two were trampled to death by a passing elephant. Dogs could also alert their human companions to human enemies, Jan van Riebeeck describes this in early conflicts between the Cape Khoekhoen people and the Dutch East India Company in 1659. Dogs also alert people to the presence of predators of livestock. Today in Kenya, for example, annual livestock losses to predators are in the range of 1-6 %, though this understates their possible significance to individual owners.

European farmers in the 19th and 20th centuries employed shooting, traps and poisons to control jackals and reduce their attacks on sheep, precolonial herders must necessarily have depended more heavily upon dogs. Kolbe wrote about this in 1731 and describes how the Khoe-speakers would release dogs at night to guard livestock.

Mitchell suggests when and how dogs came to be part of the lives of southern African herders merits more research. Noting that it might be productive to look at the taphonomy of other faunal assemblages where sheep are prominent to see if there is evidence for canine-induced modification. Sheep do not travel by themselves, they needed to be looked after. Previous authors have proposed that dogs and livestock spread together in the Neolithic Sahara. And, it seems likely that success in a carnivore-rich African landscape would have been very difficult without the help of the dog.

Today, dogs are being used in southern Africa to protect sheep from local predators. There is a dual benefit because the dogs guard the sheep from the endangered cheetah and protect the cheetahs from being shot by the farmers. Anatolian sheep dogs are being used for this purpose. However indigenous dogs are still present in southern Africa, they are free-ranging and still exhibit behaviors involved in guarding livestock. For more on indigenous African dogs see the AfriCanis website; The story of the African Dog by Johan Gallant. And, SOS Dog, The purebred Dog Hobby re-examined by Johan and Edith Gallant.  

Citation

Mitchell, P. (2014). The canine connection II: dogs and southern African herders. Southern African Humanities, 26, 1-19.

Abstract: Is black coat color in wolves of Iran an evidence of admixed ancestry with dogs?

A European black wolf, by Charles Hamilton Smith

Abstract: Melanism is not considered a typical characteristic in wolves of Iran and dark wolves are believed to have originated from crossbreeding with dogs. Such hybrid individuals can be identified with the combined use of genetic and morphological markers. We analyzed two black wolves using a 544 base pairs (bp) fragment of the mtDNA control region and 15 microsatellite loci in comparison with 28 dogs, 28 wolves, and four known hybrids. The artificial neural networks (ANNs) method was applied to microsatellite data to separate genetically differentiated samples of wolves, dogs, and hybrids, and to determine the correct class for the black specimens. Individual assignments based on ANNs showed that black samples were genetically closer to wolves. Also, in the neighbor-joining network of mtDNA haplotypes, wolves and dogs were separated, with the dark specimens located in the wolf branch as two separate haplotypes. Furthermore, we compared 20 craniometrical characters of the two black individuals with 14 other wolves. The results showed that craniometrical measures of the two black wolves fall within the range of wolf skulls. We found no trace of recent hybridization with free-ranging dogs in the two black wolves. Dark coat color might be the result of a natural combination of alleles in the coat-color-determining gene, mutation in the K locus due to past hybridization with free-ranging dogs, or the effect of ecological factors and adaption to habitat conditions.

Citation

Khosravi, R., Aghbolaghi, M. A., Rezaei, H. R., Nourani, E., & Kaboli, M. 2014. Is black coat color in wolves of Iran an evidence of admixed ancestry with dogs?  Journal of Applied Genetics, 1-9.

Dingoes recognized as a full species

Photo credit. André Geißenhöner

Scottish zoologist Robert Kerr published the first volume of what would be the two volume The Animal Kingdom in 1792. On page 144 he used the combination Canis antarctitus for the Australian wild dog. The following year, Friedrich Meyer a German physician and naturalist again described the Australia wild dog on pages 33-35 of his 1793 book Systematisch-summarische Uebersicht der neuesten zoologischen Entdeckungen in Neuholland und Afrika, (a volume that mostly focused on African primates and birds). The name dingo was long applied to the Australian dogs but Kerr’s name Canis antarcticus was overlooked. But, C. antarcticus should have had priority given it was published before Meyer’s description. ICZN Opinion 0.451 suppressed Kerr’s name and Meyer’s Canis dingo became the approved scientific name for Australia’s wild dogs to maintain nomenclature stability.

The dingo, is Australia's largest land predator as well as a controversial taxon threatened by hybridization with domestic dogs. Dingoes are thought to have arrived in Australia more than 5000 YBP (Years Before Present), and because of their isolation they became a unique canid. How to distinguish ‘pure’ dingoes from dingo-dog hybrids is an issue that has been recently dealt with in a paper by Crowther et al (2014).

 Crowther et al. notes that the confusion exists because there is no description or series of original specimens against which the identities of putative hybrid and ‘pure’ dingoes can be assessed. Current methods to classify dingoes have poor discriminatory abilities because natural variation within dingoes is poorly understood. Also, it is unknown if hybridization may have altered the genome of post-19th century reference specimens. The new research provides a description of the dingo based on pre-20th century specimens that are unlikely to have been influenced by hybridization.

The authors reasoned that because Australia was colonized by Europeans in 1788 and was only sparsely inhabited by European settlers prior to 1900, dingoes collected before this date would be less likely to have been influenced by hybridization with domestic dogs. A search for museum specimens collected prior 1900 produced a sample of 69 dingo skulls and six skins as well as specimens collected from archaeological and paleontological deposits dated before 1900. They used radiocarbon (C14) dating to determine if specimens from cave deposits lacking data on their context pre-dated 1900. Selected for comparison were domestic dogs of similar size which were or have frequently been used as stock-working dogs and hunting dogs in Australia. Thus it is likely they have interbred with dingoes. These breeds included Australian cattle dogs, kelpies, collies and greyhounds.

They found dingoes differ from the domestic dog in having a relatively larger palatal width, a relatively longer rostrum, a relatively shorter skull height and a relatively wider top ridge of skull. The pre-20th century dingoes were also found to lacked dewclaws on the hind legs. In the sample of 19th century dingo skins they found considerable variability in the color and including various combinations of yellow, white, ginger and darker variations from tan to black.

Diagnosing the dingo remains difficult due to the overlap in morphological characters with domestic dogs, localized adaptations in dingoes and morphological variation through time. Identification of diagnostic morphological characters is also difficult, especially when there is more variation within the domestic dogs in shape and size than in the entire canid clade. The morphological analyses showed that there is considerable overlap between domestic dogs and dingoes for most morphological characters. This was particularly the case for some Australian breeds, such as the Australian cattle dog, which are thought to have dingo ancestry. A similar degree of overlap in shape exists between North American wolves and closely related husky dogs.

Recognizing the dingo as a full species is likely to remain controversial. But, lineage based species concepts will likely accept the dingo as a species. The full article is available on-line.

Citations

Crowther MS, Fillios M, Colman N and Letnic M. 2014. An updated description of the Australian dingo (Canis dingo Meyer, 1793). Journal of Zoology, 293: 192–203. doi: 10.1111/jzo.12134.