News: Guest Posts
The more I consider the continuing debate over the “time” and “place” for the transformation of wolf into dog, the more I become convinced that the puzzle remains unsolved because of human devotion to a simplistic, clever-sounding idea that never made sense in the first place. As first put forth by Raymond Coppinger, that idea was that wolves feeding on the garbage piles of quasi-permanent Mesolithic villages grew tamer over the course of generations until they no longer feared or threatened humans. In the process of taming themselves, those wolves also became less fearful of and aggressive toward humans. They were cute, too. For reasons that were never clear to me, people took these cute obsequious dump divers into their homes, where they blossomed into dogs.
Coppinger pinned his argument on Dmitry Belyaev’s experiment, begun in 1959, at a Siberian fur farm, in which a group of foxes was bred for tameness alone and within ten generations was producing foxes that resembled dogs with floppy ears, piebald coats, and a high need for attention. They were juvenilized in behavior as well as appearance.
There are a number of reasons why the foxes are not a good model for origins of the dog, and I have elsewhere addressed them in detail. For now, suffice it to say that dogs arose not in quasi-permanent Mesolithic villages but in Paleolithic hunting camps. They were not sought nor selected because they solicited attention and showed no aggression—these are hardly traits of a good guard, which was one of the tasks of early dogs. Guarding remains a major reason why people keep dogs.
But the greatest problem with the self-domesticating theory is that it shuts the most creative creature on the planet out of the process. To put it bluntly, that makes no sense. Humans have always collected, tamed, and trained animals. It is inconceivable that they would ignore one as intelligent and inquisitive as the wolf.
Genomics and its offspring have shown that living organisms are not biological machines but energetic systems supported by layers of complexification. Genomics has also contributed to a more dynamic view of “domestication” as a process involving the interplay of biological, environmental, and cultural forces. The hard line between “domestic” and “wild” –always imaginary but not less real for that—has for the dog become increasingly difficult to find despite the distortions that define the current period of breedism. I am using “breedism” to refer to all aspects of the cult of the purebred dog that began to take hold about 200 years ago. Of course, there are significant differences between dogs and wolves, when they are in their own environments, but what happens when the dog goes native or the wolf becomes a lay-about?
It sometimes appears that every new find simply raises new questions while leaving old ones unresolved. That trend is apparent in two new papers by Ya-ping Zhang, a leading Chinese geneticist, who collaborated with geneticists from China and two different labs in Sweden and California on two new papers promoting Chinese indigenous dogs—native or village dogs—as the closest dogs to the ancient type.
Working with Peter Savolainen, of Sweden’s Royal Institute of Technology, Zhang has over the past decade or so insisted that dogs originated in southeast China no earlier than 16,000 years ago, and many researchers elsewhere adopted his argument despite the notable absence of dog or wolf remains from that region at that date and the presence of dog remains from other places considerably earlier.
The researchers redid the numbers using new chips that spot changes in the genome including so-called single nucleotide polymorphisms, or SNPs, and indels—insertions or deletions of small amounts of genetic material. SNPs and indels can be used to measure degrees or years of separation of discrete groups of organisms. Crunching the numbers and running regression analyses, they found that southeast China village dogs separated from wolves 32,000 years ago. There were a lot of them by then, too, they reported in an article in Nature Communications [subscription required], with Guo-dong Wang and Weiwei Zhai as first authors and Zhang as senior author—8,500 dogs by their estimate.
The new date fits nicely with some “early dogs” identified from the Altai Mountains, Belgium and the Czech Republic, although Zhang and his colleagues are not quite willing to admit that those animals are dogs. In fact, they appear to want to deal with the early date by using it to mark the beginning of a long period of self-domestication for a group of scavenging protodogs.
Zhang’s group declares: “Early wolves might have been domesticated as scavengers that were attracted to live and hunt commensally with humans. With successive adaptive changes, these scavengers became progressively more prone to human custody. In light of this view, the domestication process might have been a continuous dynamic process, where dogs with extensive human contact were derived from these scavengers much latter [sic] when humans began to adopt an agricultural life style.”
The operative words here are “commensally” and “scavenger.” Together, they say that wolves were drawn to human garbage or some other waste and so started hanging around and hunting with them but without having a discernable effect or bringing them any benefit—thus, the term “commensally”—until the biped started farming. Then the scavengers showed their true worth as crossover omnivores and became dogs.
That is not complex, but it is convoluted. At a basic level, it is not clear why protodogs could not have arrived in southeastern China from the Altai Mountain region, for example, where the people who would come to enter the New World and spread through much of the Old World as the glaciers began to retreat, had gathered, presumably with dogs some 35,000 years ago. A population of dogs and people could easily have gotten to southeast China and radiated outward from there. The much trumpeted diversity of dogs in the region could be a result not of their origins there but an accident of geography and history, including intensive breeding of dogs for food and a settlement pattern that featured many small riverine villages along the Yangtze River, one of the world’s largest.
Zhang’s defense for the lack of wolves in southeast China is that wolf populations have changed everywhere, and so no one has an ancestral wolf for study and comparison. But the Chinese indigenous dogs and a couple of related breeds, are the dogs closest genetically to wolves, and that makes them all the more important as living artifacts, Zhang and his team reason. Specifically, they looked for genetic loci that might show positive selection pressure in dogs and humans and therefor might represent parallel evolution in the two species. The genes they identified as likely candidates are involved in diet, specifically the ability to digest grains; metabolism; cancer and neurological processes, especially some involving the neurotransmitter, serotonin.
Zhang is also corresponding author with Dong-Dong Wu, both of the Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China, on a Molecular Biology and Evolution paper involving the laboratory of Robert K. Wayne, dean of canid evolutionary biologists, and several of the next generation of dog geneticists who have already published important work—Bridgett vonHoldt and Adam Boyko. They were especially focused on the prefrontal cortex and on parts of the brain that appear involved in fear response and sociability.
I say “sociability”, but, following Zhang’s lead, the researchers on these pages say “tameness,” while continuing to cling to the Soviet fox experiment as evidence that the dog was self domesticating, becoming obsequious and ingratiating and nonaggressive while eating garbage and offal. Standard descriptions of this work are abundant, and I won’t repeat them here. But it is fair to say that grand pronouncements about the working of the brain must be treated cautiously.
Most of these searches for genes involved in the transformation of wolves to dogs are based on at least two significant, faulty assumptions about the behavior of dogs and wolves. The first faulty assumption Is that wolves are now, and were in the late Pleistocene, aggressive competitors with humans. There is evidence documenting not only friendly but also mutually beneficial relationships of humans and wolves going back thousands of years. There are suggestive associations of wolf and Homo erectus remains going back hundreds of thousands of years.
The second faulty assumption is that a group of wolves effectively said to humans, “Because we like your leavings so much, we will stop vying with you and aggressing against you. We will be abject before you if you will give us excretia to eat because we cannot live by ourselves.” The question I always ask is, would you want such a creature in your house, in your bed? That is unlikely. This assumption is faulty because there is no evidence that wolves generically dislike or even fear humans. The global wolf recovery with wolves living in ever closer proximity to humans proves that wrong. It is humans who hate wolves.
That wolves and humans, similar as they are in so many ways, should make common cause, should surprise no one. Hunters study hunters. Species cooperate. It would be more aberrant if they did not. Coral groupers, Napoleon wrasse, and moray eels were recently shown to hunt cooperatively, for example. Around the world, hunting cultures had dogs that often interbred with, sometimes were indistinguishable from wolves. In the New World and elsewhere that situation was contemporaneous with the rise of multiple refined breeds in the Anglo-English speaking world.
In a real sense, then, what we call domestication of the wolf was really a rolling and flexible bringing into human culture of wolves who had the psychological and emotional capacity for sociability, for forming strong bonds not just with another individual but also with another species.
Some years ago Adam Miklosi and his colleagues compared hand reared wolves to dogs. The lengthening of the first critical socialization period and a greatly increased capacity to form strong bonds to another species were clearly central to the appearance of the dog, they concluded.
Yet for all of their problems, these two new studies are useful for their focus on indigenous dogs, the landrace dogs who although they might have several uses are generally not bred by humans to any purpose, but who still live, reproduce, and die in human society. How ancient or basic these dogs are is not really known. But they are found around the world, and I think that comparative studies of them and resident wolves and truly self-sustaining feral dogs, where they still exist, will prove most interesting. The same applies to comparison of DNA from ancient dogs and wolves. We do not yet see them clearly.
This article first appeared on Dog’s Best Friend at Psychology Today, it is used with persmission.
Mark Derr is the author of six books, ranging from Some Kind of Paradise, an environmental history of Florida, How the Dog Became the Dog, Dog's Best Friend, and A Dog's History of America. As an expert on the subject of dogs, he has been a guest on such programs as The Charlie Rose Show and Fresh Air. His articles and opinion pieces have appeared in the Atlantic Monthly, Wall Street Journal, Huffinton Post, Natural History, The Bark, Smithsonian and The New York Times. He lives in Miami Beach, Florida.
Culture: Science & History
Village dogs’ genetic code may hold clues to canine evolution and health
Like classic twin studies that investigate the interplay of nature and nurture, comparing the genome of village dogs to modern dogs may help disentangle the long-term evolutionary effects of genetic and environmental influences.
Mastiff to Min-Pin, Corgi to street cur: all dogs share the same set of roughly 20,000 genes. What makes one dog different from another—or, in the case of purebreds, almost the same— is how the genes are expressed and restricted from being expressed, and how they communicate with one another. Therefore, it may be safe to say that each of the world’s 800 to 900 million dogs is a distinct combination of different versions of the same genes. Or maybe not. At least, that’s what some scientists suspect, and they think they’ll find answers in the DNA of the ubiquitous, free-ranging canine outcasts that populate developing countries throughout the world.
While village dogs were being socially shunned, modern dogs—a subpopulation that likely split off from village dogs thousands of years ago—were serving society. So tightly woven into the fabric of our lives that we rarely think of them as human-engineered, dogs have been refined for increasingly specialized tasks such as hunting, transportation, protection, warfare, ornament and companionship. As a result of rigorous artificial selection over a long period of time, many of their ancestral gene variants are suppressed. Some have disappeared altogether, creating a fragile homozygous genome that has little diversity.
In contrast, village dogs are barely tolerated by society. Although considered a domestic species, they are the products of thousands of years of natural selection. Consequently, their heterozygous genomes are robust and extremely diverse. In addition, it’s possible that long after modern dogs branched off from the family tree, some village dog populations may have developed new gene variants that protect their immune systems.
Evolutionary biologist Adam Boyko, assistant professor in the Department of Biomedical Sciences at the Cornell University College of Veterinary Medicine, is confident that comparing and contrasting the two branches of the domestic canine family tree will provide answers to some of the mysteries that continue to surround the evolution of the domestic dog: When and where were dogs domesticated? What were the global migration paths of humans and dogs? What genetic changes occurred when wolves became dogs? Which genes are responsible for extreme size, shape and behavior differences? What are the underlying causes of genetic diseases? And how do parasites have an impact on canine well-being?
As a postdoctoral student at Cornell, Boyko worked under the tutelage of Carlos Bustamante, now professor of genetics at the Stanford School of Medicine. Curious about how the underappreciated and even less-studied village dog genome might reframe our current understanding of canine evolution and domestication, Boyko and Bustamante persuaded Ryan and Cori Boyko (Boyko’s brother and sister-in-law, who were then both graduate students in anthropology at the University of California, Davis) to add a few side trips to their otherwise romantic African honeymoon. Their instructions were to catch semi-feral, uncooperative village dogs and draw blood samples, then ship the samples back to the lab for analysis. Information from the preliminary DNA samples indicate that the researchers are on the right track. I asked Dr. Boyko about his research, and if it has future application to invigorating the health of our companion dogs.
Jane Brackman: How will mapping the genome of the village dog help us understand the mechanisms of traits in modern dog breeds?
Adam Boyko: Geneticists have spent a lot of time looking at purebred dogs. When something is selected for, either by natural or artificial selection in a population, geneticists can tell because of the patterns that are left in the genomes of individuals in those populations. In humans, for example, we can clearly see that lactase persistence, the ability to digest milk into adulthood, was selected for in some populations.
When we look for these patterns in purebred dogs, we find that things like ear f loppiness and tail curliness are driving these patterns, or short legs or small/big size. Basically, we find the effects of artificial selection by humans for breed standards. If we did a similar scan for selection in village dogs, perhaps some of those same genes would show patterns of selection, but I think we’d also see a new class of genes showing patterns due to natural selection.
For example, maybe there was a lot of selection in early dogs for genes in certain metabolic pathways because there was such an extreme dietary shift from wolves to dogs. Or maybe new parasites and pathogens caused selection at genes influencing the immune system. Or maybe we’ll see selection around genes that influence behavior and temperament.
Basically, there are all sorts of theories about how dogs became domesticated and what makes a dog a dog. When we look at purebred dogs, the main thing we are able to see is what makes certain dog breeds look and behave one way versus another. Maybe by looking at village dogs, which are much less influenced by the strong and recent artificial selection taking place in breed dogs, we’ll be able to see patterns of selection that occurred earlier in dog history.
JB: Might your findings have application for the future? For example, if you were to come across genes influencing the immune system, would breeders be able to use that information to revitalize the pedigreed-dog immune system?
AB: It is certainly true that my research may find a new MHC-type immunity gene [the major histocompatibility complex mediates the immune system’s white blood cells] that has been lost in many purebred dogs and which could reinvigorate their immune diversity. Or perhaps it will find variants associated with diet, and make us start considering a dog’s genetic makeup when making dietary recommendations. But I’m really not comfortable speculating, since I’m likely to be quite wrong in these predictions.
For example, I would have never guessed that deliberately infecting patients with intestinal parasites [Helminthic therapy] would cure ulcerative colitis, but that seems to be the case, and signatures of selection in the human genome help explain why.
But having said that, I think looking at the genomes of village dogs will be extremely useful. For example, we could get a better picture of the kinds of traits that were selected for in natural dog populations, including disease resistance, which might give us useful insights into diseases we diagnose in our pet dogs.
Conversely, as veterinarians and geneticists find more mutations that cause disease or unique traits in dogs, we can look at the genomes of diverse village dogs to see when and where these mutations arose, and whether they are also found in any other village or purebred dog populations.
It’s a really exciting time to be a canine geneticist, as we have all these new genetic tools at our disposal and many, many purebred and free-ranging populations that have yet to be characterized genetically.
JB: Some populations of village dogs, such as those you’re studying, have been isolated for many thousands of years, evolving under pressures that the stem parents of modern breeds were never exposed to. Is it possible that these dogs have “new” gene variants that don’t exist in the genome of modern breeds?
AB: It’s certainly possible, and it’s something I’m very interested in. For example, my lab is looking at free-ranging dogs in the highlands of Peru to see if they have any genetic adaptations for high altitude. Perhaps more importantly, some village-dog populations might harbor disease-resistant variants for parasites or pathogens that are prevalent in their area, but these variants might not have made it into modern purebred dogs, since those breeds were mostly founded elsewhere.
JB: How urgent is it that we learn more about these ancient dog genomes?
AB: We know how quickly pre-Columbian Native American breeds were lost when Europeans brought dogs with them to the New World, and we see that it will happen like that very soon in other remote parts of the world. So we’re working as fast as we can to get the data before the dogs are gone.
JB: What’s going on in your lab now?
AB: We’re collecting DNA samples and the genetic information we need so we can start piecing together what’s going on in these interesting but largely neglected free-ranging dog populations. We are seeking insights into dog population history to discover patterns of selection around certain genes that can then become the basis of further study. Our work is very hypothesis-driven. We have certain hypotheses about how dogs evolved, and we try to collect the right samples to test these hypotheses.
As geneticists learn more about how genetic variation controls complex traits in purebred dogs, we find it’s quite different than what we see in humans. Why? There are at least two competing hypotheses, and by gathering data from free-ranging dogs, we can start testing them to figure it out. Some of this gets into technical discussion about genetic architecture, recombination, epistasis and pleiotropy and such, so I’ve avoided getting too academic. But I also don’t want to be dismissive of it since those technical, hypothesis-driven aspects of the project are the bread and butter of my lab in terms of student training.
JB: In longitudinal studies such as the Morris Animal Foundation’s Golden Retriever Lifetime Study, researchers gather information from participants’ DNA and then match what they find to traits the test dogs may display over a lifetime. Will you have an opportunity to see how, for example, an immunesystem mutation affects a village dog’s health as it ages?
AB: Our project is a huge undertaking, and there’s a ton of data we’d love to gather on each dog but just simply aren’t able to since, at this point, we’re focused on sampling as many dogs from as many populations as possible to maximize the amount of diversity we can analyze. I really don’t want to overstate what we’re able to do in one visit to check out a dog and draw blood, which is limited to looking for genetic signatures in the genome of these dogs showing signs of selection and/or local adaptation.
But, since we have a fairly good idea of what genes do in modern dogs, at least in a rough sense, if we see a genetic signature in village dogs for positive selection around a gene we know is involved in immune function (for example), that’s a big discovery.
JB: At the risk of oversimplifying, say you’re looking at a region that you know to be linked to a negative trait and you see that the switch is turned off in the village dog DNA and turned on in modern dog DNA—would you feel that you’d found a “smoking gun”?
AB: It’s possible. Then, of course, as you allude, we would want to go back, look at dogs carrying that mutation versus other dogs, and see if there are different health outcomes. Perhaps [dogs with the mutation] are more resistant to intestinal parasites or perhaps they are more prone to autoimmune disease or something. Until we find the mutations, it’s a bit speculative to make predications about what exactly the findings will mean to owners. This is certainly “basic research” in the purest sense.
JB: In people, size is determined by hundreds of genes, each with a small effect. In purebred dogs, body size can be regulated by a single gene. Is this unique to dogs?
AB: It depends. There are other traits in other species controlled by a couple of loci [location of a gene on a chromosome]. I would argue that yes, it’s pretty unique. Whether or not dogs are special in that there is something about their genome that predisposes them to this type of diversity, or perhaps because humans worked so hard at creating them, we don’t know. This debate is still raging in the literature. It is definitely the case that genes have many, many effects. Rather than being a blueprint in which each gene is responsible for just one part of building the whole organism, the genome is more complicated, with each gene taking on different roles at different times or in different tissues.
JB: Do multiple-trait relationships also show up in village dogs?
AB: I think this would also occur in village dogs if the mutations were in those populations. The difference is that selective breeding has actively promoted these large-effect, diversifying mutations in dog breeds, making them relatively more common. Natural selection usually selects against such large-effect mutations in natural populations. You won’t see a short-legged wolf because it couldn’t hunt.
In fact, most of these large-effect mutations probably first arose in village dogs. The difference is that these mutations aren’t usually beneficial to village dogs, but the ones that aren’t too detrimental might persist at low frequency long enough for humans to start trying to promote breeding of that trait. Take achondrodysplasia [a type of dwarfism]. It almost certainly arose in village dogs, but to a free-ranging dog, super-short legs and all that comes with them probably aren’t much of a selective advantage. But once folks started looking for dogs to turn their spits, they found these super-short dogs to be useful, and eventually that genetic variant made its way into a whole host of modern breeds.
For the specific achondrodysplasia mutation, I don’t know if that is the exact story, but I do think this is likely to be the case for many large-effect mutations. Depending on how early in dog evolutionary history the mutation arose, it could be found in most regional village dog populations, or it could be restricted to certain populations that are close to where it first arose. Lots of research still left to be done!
JB: As a lifelong dog lover, you must find it difficult to see the deplorable conditions in which some of these dogs live.
AB: There’s so much disease in these high-density populations. As these communities become more urbanized, dogs are living like rats and pigeons. Getting DNA on these populations is not enough of a reason to allow the animals to exist like this. Life on an urban street is rough existence.
JB: If you adopt a village-dog puppy and raise it in a typical Western environment, what kind of dog will you have?
AB: Adopting the dogs is not part of our project, but we know people who have done this. They can be great dogs. They don’t have some of the aggression issues you might see in some of our dogs, because they are culled for aggression, or for eating a chicken. There are some things that aren’t tolerated. So you might say that people in the villages impose a form of selection. The dogs are smart and resourceful. They seem to adapt.
Good Dog: Behavior & Training
Benefits of lower protein and higher fat
It’s not news to anyone that the food that we feed our dogs matters. The right food may translate to better health, proper weight management, longer life, a shinier coat, and better performance in a range of sports and activities. New research suggests that the diet of working detection dogs can even have an impact on their ability to smell.
Joseph Wakshlag at Cornell and his colleagues at Auburn University found that dogs who were fed more fat and less protein than typical diets contain were better able to detect certain scents such as TNT, ammonia nitrate and smokeless powder. Over a year-and-a-half, they rotated dogs through three diets and compared their detection abilities when they were on each diet. The three diets were: 1) a high quality performance diet, 2) regular adult dog food and 3) regular adult dog food combined with corn oil. The ability to detect scents was highest when the dogs ate the diet of regular dog food combined with corn oil. That diet had less protein but the same amount of fat as the high performance diet. The high performance and regular diets had equal amounts of protein, but the high performance diet had more fat.
Digesting protein causes a rise in a dog’s body temperature, as does exertion in the form of physical activity. The panting that is essential for lowering body temperature reduces a dog’s ability to smell well. In order to do their detection work as effectively as possible, dogs must cool down so that they are not panting. A diet higher in fat and lower in protein seems to allow dogs to cool down faster and therefore smell better.
What constitutes a high performance diet may depend on the sort of performance that is desired. Dogs who work by running or pulling hard may need more protein to succeed at their job than dogs who need to be able to maximize the effectiveness of their olfactory abilities.
The American Heart Association issued a scientific statement yesterday that yes, owning a dog may protect us from heart disease. The statement was issued by an expert panel that was convened to look at alternative approaches to combat heart disease. They were prompted to look at the benefits of pet caring because of the growing number of medical studies linking pet ownership to better health.
Dr. Levine, a professor at the Baylor College of Medicine said, “there are plausible psychological, sociological and physiological reasons to believe that pet ownership might actually have a causal role in decreasing cardiovascular risk.” Dog ownership, partially because it compels people to walk their dogs and thereby getting more exercise, proved more beneficial than owning a cat. Richard Krasuski, a cardiologist at the Cleveland Clinic, thought this statement as more of an indictment of societal attitudes toward exercise. “Very few people are meeting their exercise goals,” he said. “In an ideal society, where people are actually listening to physician recommendations, you wouldn’t need pets to drag people outside.” (Feeling that walking my dogs is one of the greatest daily pleasures in my life, I would not quite agree that many of us actually consider our dogs as “dragging” us outside.)
“Several studies showed that dogs decreased the body’s reaction to stress, with a decrease in heart rate, blood pressure and adrenaline-like hormone release when a pet is present as opposed to when a pet is not present,” Dr. Levine said. Pet owners also tended to report greater amounts of physical activity, and modestly lower cholesterol and triglyceride levels. Some research showed that people who had pets of any kind were also more likely to survive heart attacks. All in all a definite win-win for us and our dogs.
The research also strongly suggested that there was a sharp contrast between those who walked their dogs themselves and those who did not.
Dr. Levine concludes by saying that they were not recommending that people adopt pets for any reason other than to give them a good home.
“If someone adopts a pet, but still sits on the couch and smokes and eats whatever they want and doesn’t control their blood pressure,” he said, “that’s not a prudent strategy to decrease their cardiovascular risk.”
Good Dog: Behavior & Training
Its association with lifespan and cause of death
In a new study called Reproductive Capability is Associated with Lifespan and Cause of Death in Companion Dogs, researchers report on the links of reproductive status (intact or spayed/neutered) with both lifespan and cause of death. Previous studies have suggested that sterilization increases the risk of certain cancers. However, if spaying and neutering actually does increase life span, then any cancers that are more common in older dogs may only appear to be more common in sterilized dogs because sterilized dogs live longer.
The overall conclusions of this new study are that there is a link between lifespan, cause of death and reproductive status. Sterilization was associated with longer lifespan. The mean age of death for intact dogs was 7.9 years and for sterilized dogs was 9.4 years. Sterilization increased life expectancy 13.8% in male and 26.3% in females.
In this study, researchers found differences in the cause of death between the reproductively capable group and the sterilized group. Compared to reproductively capable ones, dogs who were spayed and neutered were more likely to die of cancer and immune-related diseases, but less likely to die from infectious diseases, trauma, vascular disease and degenerative diseases. These differences in causes of death were consistent when the data were compared between dogs of the same age.
Data are from 40,139 dogs in a veterinary teaching hospital who died from 1984 to 2004. Juvenile dogs, dogs with a congenital issue that caused death, and dogs whose reproductive status, cause of death, or age were unknown were eliminated from the over 80,000 dogs originally considered for inclusion in the study. Reproductive capability was defined in this study as intact versus spayed or neutered, and does not mean the sterilized dogs had not reproduced. It’s unknown if they had reproduced prior to being sterilized. There were no data on how many times intact dogs had reproduced, only that they were still reproductively capable.
Though the results of this study are intriguing, it is important to recognize the limitations in the data and therefore in the conclusions. Though the groups—intact or sterile—are assumed to differ in no other way, that may not be the case. It is possible that the members in the sterilized group have received more regular or better medical care throughout their lives, for example. The sterilized dogs may come from different sources such as rescue groups or shelters rather than from pet stores or breeders. In other words, differences in life span or cause of death may not relate to reproductive status, but to one of these other factors. This study shows links of reproductive status with lifespan and cause of death, but we cannot assume that reproductive status is the cause of these differences. They may be correlated for some unknown reason.
Some other concerns I have about the data are that the dogs had all been referred to a veterinary teaching hospital for medical reasons, which means that the dogs in the study may be largely dogs with serious health issues rather than typical dogs. This means that conclusions based on this study may not be applicable to dogs in general.
I’m glad that studies are expanding on the question of lifespan and reproduction by looking at causes of death instead of just reproductive capability. I think this study is a great start at exploring questions that are of interest to all of us who love dogs, but I do think we need to exercise caution in order to make sure that we are distinguishing between studies that show correlations between various factors and those that demonstrate a causal relationship between those factors.
Good Dog: Studies & Research
Unlike our dogs, who have an aptitude for biting off more than they can chew (if they chew at all), when it comes to fulfilling our fitness resolutions, we might be more successful with a modest approach. Take, for instance, recent findings that only 150 minutes a week of moderate activity (such as brisk walking) can extend our lives by 3.4 years! A daily dose of 22 minutes might seem like a trifle to dog people, most of whom have this covered with dog-walking duty (albeit, probably not at a “brisk” pace). We also learned about the perils of prolonged sitting. As reported in the New York Times, it causes even the incidence of diabetes to go up: “When muscles don’t contract, they require less fuel, and the surplus, in the form of blood sugar, accumulates in the bloodstream, contributing to diabetes risk and other health concerns.” Suggested remedies? Get up more often, put down the remote, talk on the phone standing up. To that list, we add, play with or walk your dog (briskly!). Put some spring in your step. Your dog will be happy to help.
Dog's Life: Lifestyle
Dogs’ behavior suggests they understand it
Dogs take the human perspective into account when deciding whether to take food that they have been told not to take. This is the conclusion of a recent series of experiments by Juliane Kaminski, Andrea Pitsch and Michael Tomasello described in a research paper called Dogs Steal in the Dark.
The experiments all had a similar set up, in which a dog was in a room with a food item on the floor. Dogs were pre-tested to ensure that they understood the cue not to take the food. They were told not to take the food and then the experimenters recorded whether the dog took the food or not and if so, how long it took for them to do so. In the first experiment, a human was present in the room and there were four conditions: 1) the food and the human were both in darkness, 2) the food was illuminated but the human was in the dark, 3) the food was in the dark but the human was illuminated, and 4) the food and the human were both illuminated.
The dogs took the food most often when both the food and the human were in darkness, and least often when they were both illuminated. The dogs took the food faster when it was not illuminated, but whether or not the human was illuminated had no effect on the time until the food was taken. These results suggest that the level of light in the room had an influence on the dogs’ behavior.
In the second experiment, the food was either illuminated or in the dark, but the human left the room after giving the cue not to take the food. The goal of this experiment was to determine if dogs were avoiding food when it was lit. The results were that the dogs almost always took the food no matter what light situation it was in, but they took it faster when it was illuminated than when it was in the dark. This indicates that the dogs are not simply avoiding food that is illuminated.
In the third experiment, the researchers investigated whether the overall amount of light in the room was important to dogs or whether they were responding to the specific location of the illumination. There were two different situations tested. For one group of dogs, the human in the room was always illuminated. Half the time, the food was illuminated, and half the time the light was directed at another spot in the room. For the other group of dogs, the human in the room was always in the dark and half the time, the food was illuminated, and half the time the light was directed at another spot in the room.
In this study, whether or not the human or the food was illuminated had no influence on the likelihood that the dogs took the food, but they waited longer to take the food when it was illuminated. This suggests that the location of the lit area matters, as opposed to dogs just reacting to the overall amount of illumination in the room. This shows that the visibility of the human is not the factor that causes the difference in behavior.
Overall, the conclusions drawn from these studies are that dogs do take into account illumination when taking food that they have been told not to take. Dogs were more likely to take the food when it was dark compared to when it was light. They took the food faster when the food was in darkness when a human was present, but took the food faster when it was illuminated when they were alone. Whether or not a human in the room was illuminated did not affect their behavior.
This research supports the idea that dogs are aware of and consider the human point of view when deciding whether to take food or not. To put that into a larger context, this relates to the ever-increasing body of evidence that dogs have a theory of mind, meaning they have an understanding that other individuals have different perspectives, knowledge and emotions.
This is very well done research that teases apart a number of variables to add to what we know about the canine mind. Unfortunately, most of the articles in the popular press only say, “Dogs steal more food in a dark room than in a light room,” which is a huge oversimplification of the complexity of this interesting work.
News: Guest Posts
I had watched the dog origin wars as a chronicler of the dog-human relationship for several decades when in 2009 I was approached a young editor The Overlook Press about writing a book on the origins of the dog. I readily agreed, and the result was How the Dog Became the Dog.
Pondering the conflicting dates, places, and theories associated with the emergence of the dog, I concluded that as soon as our forebears met wolves on the trail they formed an alliance of kindred spirits, and the process began. Their basic social unit was a family with ma and pa at the head and young ones of varying competency. They worked and hunted cooperatively. They were consummately social but capable of prolonged solo journeys.
It made sense that the Middle East, if not North Africa, was where this all started because that would have been the region of first contact. But because of their natural affinity, wolves and humans got together wherever they met. Some of the resultant “dogwolves”—my phrase for doglike wolves or wolves that act like dogs—created lineages that survived a while then fizzled out; others endured.
I identified several hotspots for early dogs across Eurasia and a group of humans that at least according to genetic evidence might have made its way through the cold of the last Ice Age from the Persian Gulf oasis, then a fertile land, to the Altai Mountains of Central Asia, a region that also hosts the headwaters of the Amur River, still famous for its wildlife. This group’s dogwolves mixed and matched with others along the way, especially the big mountain dogs of the Caucasus. This group of hunters and foragers gathered in the Altai around 40,000 years ago and from there ultimately took the New World.* They also went with their dogs, I calculated, south and east into China, Korea, and Japan and west again with their giant dogs, now mastiffs.
I based that conclusion in part on the types of dogs found in the New World. It made more sense that the possibility for the phenotype was present even if the phenotype itself was not manifest than that it was introduced later.
It was with some interest, then, that I read in PLoS One for July 28, 2011, about a 33,000 year old ‘incipient” dog from the Altai Mountains—that is, an early attempt at a dog that went nowhere. The finding was immediately challenged, and the fossil dismissed as a wolf, even if a strange one. So a new team of researchers redid the work in Robert K. Wayne’s evolutionary biology lab at UCLA and on March 7, 2013, published an article in PLoS One confirming that the 33,000 year-old-fossil is that of a primitive dog.
Writing for their colleagues from Russia, Spain, and the U.S., Anna S. Druzhkova of the Siberian Branch of the Russian Academy of Sciences and Olaf Thalmann of Turku University, Finland, state that when compared with other canids, the Altai dog, as it is known, shows closest affinities with New World dogs and modern dog breeds, ranging from Newfoundlands to Chinese Cresteds and including cocker spaniels, Tibetan mastiffs, and Siberian huskies.
Equally interesting from my perspective, the Altai dog does not appear to have been related closely to wolves in its immediate vicinity or to modern wolves. It came to the Altai from elsewhere, probably with people.
The researchers emphasize that there is uncertainty in their findings because they are based on a single region of mitochondrial DNA. But from my standpoint, the work provides one bit of evidence that’s I’ve not been barking up the wrong tree—and that seems worth noting.
*Ted Goebel et al., “The Late Pleistocene Dispersal of Modern Humans to the Americas,” Science, March 14, 2008. Connie J. Kolman et al., “Mitochondrial DNA Analysis of Mongolian Populations and Implications for the Origin of New World Founders,” Genetics, April 1996.
Good Dog: Studies & Research
An interview with Jeffrey Masson
This is one of the first interviews (if not the very first interview) ever to appear in the pages of Bark. It was originally published in Bark’s third issue in fall 1997—back when Bark was still printed in black-and-white on newsprint—when Jeffrey Masson first released his book Dogs Never Lie About Love.
On the day of our interview, Jeffrey Masson’s lovely Berkeley home was a bustle of activity, with friends and family popping in and out, the baby, the three dogs and the cats. There had been a wedding only days earlier and Masson was preparing for a major book tour. We were very grateful that he’d found time to squeeze us in. As we settled in for our talk, the phone rang——his agent calling to talk about Masson’s appearance on Dateline the previous night. “I’ve got to go, I’m being interviewed by the Berkeley Bark,” Masson said, cutting short talk of national TV to give this interview.
Your title is Dogs Never Lie About Love. It reminds me of a Fats Waller song, “Be sure it’s true when you say I love you, it’s a sin to tell a lie.” To me it has always been an odd lyric, because how do you lie about love, or how do you not lie about love——our emotions are so complex. What exactly do you mean by this title?
It was suggested to me by my trainer, a wonderful guy at Guide Dogs for the Blind——Mike Delosi. He said you’re gonna laugh, but I just thought of the best title your book——Dogs Never Lie About Love. Laugh!, it’s perfect! And it really is the thesis of the book, that dogs are incapable of any kid of deceit when it comes to their emotions. They don’t hide them from others and don’t hide them from themselves. We sometimes don’t know what we’re thinking and feeling and certainly often attempt to prevent others from knowing what we’re feeling. Nobody doubts this. But dogs are so upfront about their feelings. They can’t, they just can’t...
They don’t mind being the fool.
That’s right. This is who they are. They don’t think, “If I’m showing my joie de vivre they’ll think I’m unsophisticated and naive. What they’re feeling is who they are. And I think that love is really the master emotion for dogs. They really seem to have an endless supply, an endless capacity to love that just astonishes me.
You say in your introduction that you were originally attracted to the observation of wild animals because you felt that somehow the domestic dog was contaminated by association with humans. Have you changed your mind about this?
Well, I don’t really know. It’s fascinating to me that dogs feel as much as they feel and that we can read them so easily. So the question is, why can we read dogs so easily, why are they so transparent to us and we to them? There’s no other animal like that. We don’t know what a bear is feeling. You know when they’re angry, but you don’t know when they’re sad and disappointed and nostalgic and homesick and all these things that we have in common with dogs. So the question arises, did canines learn it from us or is it just some miracle of parallelism. Or is it that all animals share these things and we just can’t read them. I haven’t discovered the answer to that. I suspect one could. If you were to live with wolves long enough you might be able to say it’s clear that wolves feel the same things that dogs feel, therefore they didn’t get it from us.
Didn’t some of your studies of the wild animals, for instance elephants in the zoo, show that they have a rapport with their people?
Not like dogs, possibly, but not even cats. I have two cats here and I love them but they really don’t have that same intimate constant interaction with us that dogs have. Horses don’t, parrots don’t, no animal does.
It begs the question … Was is there from the beginning, and that’s why we got together with them?
That is an interesting question. But it’d be awfully hard to answer. I think if you knew enough about wolves, if we discovered that wolves show the same emotions with other wolves, then we could say it’s the nature of the beast——it’s not us. But I suspect that it is us. Because dogs are so eager to please us and understand us. When I first got my three dogs, I thought——I can’t do this. It’s just too much, three big dogs walking around Berkeley, how am I going to get them out of the car and into this park without putting each one on a leash. I can’t do it. And lo and behold it was really easy after a while. They figured out what I want from them and they give it to me. It took time, and I didn’t train them. It’s just that they watched me and observed me long enough to figure that “Oh, he want us to do this! Ok, I get it, I can do that.” And that’s amazing! Cats don’t do that, they may know what you want, they just don’t care.
In fact, some part of them may know what you want and do …
...the opposite. And a dog will never do that. Very rarely will a dog do what he knows you don’t want him to do. Very rarely.
My dog is very willful. If he doesn’t want to do what I want him to do he won’t look at me. He pretends he can’t hear me.
Hysterical deafness in dogs.
I find your last book (When Elephants Weep) and this book almost radical because I think it’s been anathema for intellectuals to discuss emotional states in animals. Even though anyone who has ever lived with animals or worked with them in a lab could observe that.
The people who work with them in labs have a vested interest in denying that they feel. Because if you say that you think that a dog can feel pain and can suffer as much, if not more than we can, then what kind of person inflicts that pain? It’s hard. The honest ones will say yes, that animals do suffer but animal testing helps mankind. OK, I don’t agree, but you can live with that. What I don’t like is when they say animals don’t feel anything. I don’t see how they say that about a dog. I mean maybe with a rat, I don’t believe if for a minute, but I can understand someone saying he can’t see emotion in rats.
I think it’s easy for people to denigrate their own observations because of what experts say.
You have to look at what vested interest experts have. In the segment of Dateline I just did they had to have a critic talk about my book so they get Dr. Hart who’s the head of the behavioral clinic at UC Davis School of Veterinary Medicine, and he said, “Masson is totally wrong——everything a dog does is pure instinct.” And that is the cliché——that’s what they were taught and it’s very hard to get them to move away from that. You could say that about every human emotion. If a mother saves a child who’s drowning——is that instinct or love?
I expect that there are people who have those theories about humans.
I’m sure that there are. But most people who would say that about a dog would not say it about a human being. Why would a dog have an instinct to save a human being anyway? It can hardly be instinct, and there are literally thousands of stories of dogs that have saved people.
I like something you said in your introduction. You asked, “Why is a lab scientist a more reliable observer?” Most people take it for granted that scientific method is objective and that the scientist must necessarily be an objective observer.
We’ve been taught that. They say, well you’re telling us a story and that’s just an anecdote. Anecdotal evidence. What do they think they have when they’re in the laboratory? It’s just another story. And if you have enough of them, if you’ve collected a thousand similar stories, isn’t that data?
You go over how you selected your dogs and what you were looking for and I was struck that all three were females. Did that make a difference to you?
Well, my publisher was very annoyed about that. He wanted me to have a male dog. And it’s true, it would have been interesting to compare. It just so happened that all three of the ones I wanted turned out to be females. So I’m sorry, I’d like to know whether, for example, males are more aggressive than females. These three dogs are just not aggressive. They have never gotten into a fight with each other or another dog. They’re not perfect dogs by any means, little Simi gives this horrible Grrr to every dog she meets. But she’s never actually gotten into a fight, and I wonder if she were a he, would he get into fights?
They’re all so individual.
That’s true too. Certainly there are male dogs that we encounter that would never fight. And there are certain females that we meet that would. But no dog has ever fought with mine. My theory is that males will not fight with females unless they’re trained to fight. But if we’re just walking around and they do something offensive, males will forgive it right away. And females don’t seem to fight much between themselves.
My dog has a lot of propriety and he expects other dogs to be … dignified. He gives females a lot of slack, but not males.
I think that dogs can be very dignified and there’s a difference in a dog who is not and one who is. It’s an interesting quality. In a lot of the working dogs, I have the sense that they feel that there’s a way to do things and an improper way. I was hoping to get a Border Collie for that reason, but I also hear that they’re hyper. They’ve got to be doing stuff. I’m spending three, four hours a day out with my dogs, so they get plenty of things to do. I didn’t think I would spend quite that much time, but with a little baby it’s fun. I like being out anyway and since it turns out to be my research …
What a nice life. Are these your first dogs in a while?
The last dog I had was a long time ago, about six years ago. I had moved into someone’s house who left the dog behind. An old German Shepherd. And I really bonded with him, I was amazed, but it was in the last year of his life. And before that, in my previous marriage, we had a Standard Poodle for 15 years——I loved that dog! And before that it was as a child. So there haven’t been that many dogs in my life.
I haven’t really had a dog since childhood. My dog now, I feel very conscious of him and have a close bond. And I think that he’s taught me a great deal about human nature, too. I wonder what your dogs have taught you.
For me, that’s how the book came to have this thesis. I really do believe that dogs feel more intensely, more purely, more passionately with less ambivalence than I do. I can’t speak for you, or anyone else, but for me they definitely do. And I want to learn from them, and I do learn from them. How to live in the moment——dogs are very, very good at that. They’re really like little gurus. All these gurus claim to live in the moment, but don’t really do it. Dogs do it. They really live in the moment, and they don’t compare things. I still have a bad habit that I picked up from my parents of comparing one thing to another, one place to another, one person to another. Dogs never do that. I don’t know if you’ve ever been to the landfill in Berkeley, that tacky little beach opposite where we always go. But it has the world’s ugliest beach! And I took my parents there once and they said, “Jeff how can you even walk on this beach, remember when we were in the South of France and Cannes and do you remember the Italian Riviera?” And I said yeah, this is really tacky …. My dogs——they love it! They’ve been to the most beautiful beaches in the world up in Oregon and here … they don’t care! For them, it’s the moment that counts, they’re with the person they love, they’re chasing sticks, they’re jumping in the water, they’re perfectly happy——they never make those comparisons. So, those are the things I’ve learned from them. Also, I haven’t learned it, but they’re very good at forgiving. That, I’m not so sure I want to learn, but they can do it. I mean you can, I never have, but people hit dogs and a minute later the dog will lick their hand, I mean a minute later! I guess some dogs less than others, some dogs probably will remember and hold a grudge. But most dogs don’t hold grudges, they really don’t.
There is an interesting story in your book about a police dog stopping his master who’s unjustly beating a guy.
It’s a Vicki Hearne story and I believe it. It’s utterly fascinating! I wish I had observed it, I’d love to know what was going through that dog’s mind.
That’s a very complex thing!
Very complex. If that’s true it shows an extraordinary … if it’s true you don’t see it very often, that’s for sure. I asked the police here, “Does a dog ever stop a thief or a shoplifter?” No, they wouldn’t do that, they don’t care, they don’t share our values. But obviously this person had overstepped some canine value. I think it’s an utterly fascinating concept. I’ve never observed that. That’s Vicki Hearne’s. She’s very unsentimental, that was one of the few sentimental stories in her book. She’s a big trainer and I’ve seen a lot of training now and I’m not into it, it’s not my thing.
I believe she’s written about circus animal training. I just saw a film, Fast, Cheap and Out of Control, which featured a lion trainer, whose attitude toward the lions was adversarial, one of fear ….
Never turn your back, show who’s boss. A lot of dog training is like that too.
The interesting thing about the film is that the lion trainer had a protégé whose attitude was not adversarial, she built a rapport with the lions. The elder trainer had a very grudging respect for his young apprentice——well, it seems to work but someday she’s going to be sorry.
Right, it’s that way with dog training, also. I went to visit one of the legends of training, a guy named Sapir Weiss, have you heard of him? He’s an Israeli paratrooper and he’s trained dogs to carry dynamite. And he was amazing, I have to admit. I walked in and we started arguing right away. He doesn’t believe in emotion, nothing——it’s all training, it’s all conditioning. He says, “It’s all about who’s boss, and I’m the big boss and they know it and I have a way of letting them know this right away.” And I said I didn’t believe it. He said, “You know, I’ll prove it to you.” He said, “Are these three dogs very attached to you? I’m going to walk with them and you call them back to you and I guarantee you they won’t come.” I said no way. And they walked right by me and I called “Sasha, Simi, Rani,” and they looked at me like, “I’m sorry I can’t come”——they wouldn’t budge. I said, “What is this, is it a magic act?” He said, “I convey I’m the boss and they know it, I know how to communicate that to dogs. You don’t hear a single dog in my kennel of ninety dogs barking, do you? That’s because I let them know I won’t tolerate it.” It’s very impressive—I still don’t like it …. He had a dog, a fabulous Schutzhund but the dog seemed miserable, he never goes out, does everything Sapir says and looks at him in constant apprehension.
It’s hard to know how the dog feels about that, but for me, I don’t want to have that kind of relationship.
That’s a good point. I can’t say, but in my opinion, the dog would rather have a more equal kind of relationship. I can’t answer that. But I don’t want that with them, and I’m not going to train them to go blow up trains with dynamite so …. On the other hand I also went through Ian Dunbar’s training with the puppies and that didn’t work so well. I finally decided that the best training was no training—you hang out long enough with the dogs and they figure out what you want and they do it. My dogs come, they stop for traffic, they do the important things. I taught them the command “Leave It” when they’re eating horrible garbage. They do that.
My dog hasn’t got that one down.
Well, when I tell them stay they’re not going to do it, and I’m sure I could train them to do that but it would mean breaking their will to some extent, and I’m just not prepared to do that.
Yes, I don’t relish that authoritarian relationship, consequently my dog is not the perfect obedient dog.
But I think it allows them to be more of who they are. This is also the problem with guide dogs for the blind, I mean I’m very impressed with what they do and obviously it’s wonderful work and it’s wonderful for the blind people, I wonder how wonderful it is for the dog. You know this is not something the dogs would choose to do on their own, given the choice.
Well, you know I think there are some individual dogs who must want to.
Maybe, they take pride in it, yeah.
Like herding and working dogs, a lot of them really love to work and they do take pride, and that’s a big part of life.
But it’s not all of life … pleasure is also part. They’re not big on pleasure at Guide Dogs for the Blind. The dogs have a certain amount of time when they play but my dogs basically play all day. They don’t work and I think it makes them very happy. It’s very hard to judge. Who’s to say who’s a happier dog.
Your dogs have a good life.
They have a very good life.
What say you about leashes?
Berkeley must be the best city in the world to have a dog because we don’t have a leash law on the street. The police don’t always know it but I went to City Hall and got a little piece of paper with the ordinance that says if a dog is obedience trained and is under voice control then it shall be deemed to be upon a leash. The few times that the police have stopped me, I live across the street from the Berkeley Police Station, I’ve just shown it to them and they’ve been very nice about it. Most of the time I don’t get stopped, and I walk around Berkeley with my three dogs off leash, and I really like that. It’s just different, it really is different. It makes me feel that we are more equal. They can stop and sniff things, they can deviate a little bit. I mean, they still basically go where I want to go, it’s not equal in that way, but they’re free and I really like it.
On the other hand there is a leash law in the parks.
Yes there is, and I just don’t obey it. If a ranger tells me to leash them, I do. Most people don’t care. When we go to Inspiration Point for walks, most dogs are off-leash and people are very happy about it. But, at least once a walk, somebody will come to me and say, “Those dogs are supposed to be on a leash!” And the dogs aren’t doing anything, and I ask them, “Can you explain to me how they’re bothering you?” “It’s a law!” “Well you’re right, but they don’t seem to be harming anybody, and they’re getting so much pleasure, do you really want me to leash them? “Yes, I do!” You always get a few, but for research it was interesting to hear that.
Do you ever take your dogs on leash? Because it’s a very different experience.
I really don’t like to do it. Sometimes outside of Berkeley you have to. We went on a camping trip and they were very unpleasant sometimes if the dogs were off-leash so we took them on-leash in the camping grounds. I just hate it!
I think that dogs are more aggressive on-leash.
I’ve read lots of training books, and there are many different theories. Some feel that the dogs become more territorial on your behalf on lead.
I don’t understand it. Another thing I don’t get … my dogs go completely nuts when they’re in the car and we pass a car with another dog or pass another dog on the street. All three of them. Walking down the street they pay no attention.
Not even when the other dog is behind a fence?
Behind a fence, yes. Behind the fence they hate.
I once saw a baseball game when the pitcher hit the batter with a fast ball. The batter stormed the pitcher’s mound in an attitude of “Let me at ‘em.” But both players kept their arms at their sides, shoulders back. Not until teammates came to restrain them did they really start flailing. When they were safely restrained from hurting each other, the killer came out. I see this behavior in dogs behind fences. They can engage in a little aggression because they really can’t do anything.
Maybe you’re right. If they pass each other on the street they could hurt each other, but they can’t in the car or behind a fence. Interesting. But the car thing, I don’t like it and I’ve begged them to stop, but it doesn’t do the slightest good. Not the slightest good.
You were initially not interested in studying dogs—they were perhaps contaminated by their association with humans. Have you also found that you see the wildness in dogs?
Oh yes! That’s the miracle to me, that we are living on intimate terms with a wild animal. It really is, it’s a wolf. There not that much difference between wolves and dogs, and it’s a very humbling experience. Suddenly your dog does something or howls and you feel my God, this is a wild animal and it has accepted me and we are living together! And no other animal gives you that … well cats a bit too, because they really are tigers. But dogs even more, and it’s just such a miracle to me. I can’t get over it.
News: Guest Posts
Dogs and wolves share a similar genetic profile. So why are their behaviors so different?
The reasons aren’t clearly understood. In a recent paper in the journal Ethology , evolutionary biologist Kathryn Lord's doctoral research (University of Massachusetts, Amherst) suggests differences in later behaviors might be related to the pups' earliest sensory experiences during the critical period of socialization, the brief period when a puppy's exposure to novel things results in long-term familiarity.
Lord's research demonstrated that dog and wolf pups acquire their senses at the same time:
· Hearing: Onset 19 days, reliable by 28 days
· Seeing: Onset 26 days, reliable by 42 days
· Smelling: Reliable by 14 days (onset likely earlier)
· Dog pups wait until 28 days to explore their environment when all senses are operational.
· Wolf pups begin exploring the world at 14 days, relying solely on scent, when they are still blind and deaf.
Although wolves are tolerant of humans and things they were introduced to during the critical period, they don't generalize that familiarity to other people or novel things when they mature. Dogs on the other hand, can generalize, and if properly socialized are not spooked by novel sounds and sights.
Why do mature dogs and wolves behave so differently? Lord's conclusion is that at the gene level, the difference may be when the gene is switched on, not the gene itself.
What could that mean? Research has shown that the brain is capable or rewiring itself in dramatic ways. Early loss of a sense affects brain development. For instance, even though the developing auditory cortex of a profoundly deaf infant is not exposed to sound stimuli, it doesn't atrophy due to lack of use. Rather it adapts and takes on processing tasks of other senses including sight and touch. Perhaps wolves see the world in smell, and dogs see it a lot more like we do.
Click here to read the paper, A Comparison of the Sensory Development of Wolves (Canis lupus lupus) and Dogs (Canis lupus familiaris), by Kathryn Lord, Ethology, February, 2013.
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