Dog's Life: Lifestyle
It matters more than brightness
One of the most persistent errors about dogs is the claim that they are colorblind. It has been known for decades that dogs can see colors, but research into the details of how they use their color vision can still reveal new information. In a recent study called “Colour cues proved to be more informative for dogs than brightness”, researchers asked the simple question, “Do dogs attend to color or brightness when learning the cues that indicate the presence of food?
In the experiment, researchers trained dogs to make a choice between boxes concealing food. The boxes were each marked with a colored paper, and the dog had to learn which one indicated a piece of meat was inside. Dogs were trained to discriminate between either light yellow and dark blue or between dark yellow and light blue. Then the dogs were tested to see if the cue they used to make correct choices was the color of the paper or the brightness of the paper.
For example, a dog who had learned to choose the box marked by a dark yellow piece of paper was tested with a choice between a box marked by light yellow or a box marked by dark blue. The experimenters were asking whether the dog had learned that “dark” indicates the presence of meat or whether “yellow” does. They found that dogs were making choices based on color, not brightness, in the majority of cases. It was a small sample size of only 8 dogs, but it suggests that dogs not only see color, which has long been known, but that they pay attention to it more than to the depth of color.
It is not surprising that if dogs have the ability to see color that they would use that color functionally in various situations. Asking whether dogs distinguish dark from light when the opportunity to distinguish by color is also present may be an important preliminary step in understanding what dogs attend to. However, I would be even more interested to know whether dogs favor color over shape, color over size or even color over various sounds to make their choices, as all of these seem more biologically relevant to dogs seeking food than brightness does.
And imitate novel human actions and store them in memory
Researchers have shown that dogs can indeed not only mimic human actions, but can retain actions in their memory. According to a new study by Claudia Fugazza and Adám Miklósi, from Eötvös Loránd University in Hungary, this deferred imitation provides the first evidence of dogs' cognitive ability to both encode and recall actions. The research is published in Springer's journal Animal Cognition.
In order to test if dogs possess the cognitive ability of deferred imitation, Fugazza and Miklósi worked with eight pet dogs who had been trained in the “Do as I do method” by their guardians. While dogs are good at relying on human communication cues and learn by watching humans (and other dogs), what this study set out to test was if dogs can perform imitatively not directly after seeing a human do it, but some time after seeing the action.
So they made the dogs wait for short intervals before they were allowed to copy the observed human action. An example of the action done by the human and then performed by the dog was ringing a bell or walking around an object like a bucket.
“The researchers observed whether the dogs were able to imitate human actions after delays ranging from 40 seconds to 10 minutes, during which time the dogs were distracted by being encouraged to take part in other activities. The researchers were looking for evidence of the dogs' ability to encode and recall the demonstrated action after an interval.”
Fugazza described how one of the tests was carried out: “The owner, Valentina, made her dog, Adila, stay and pay attention to her, always in the same starting position. Three randomly chosen objects were set down, each at the same distance from Adila. When Adila was in position, Valentina demonstrated an object-related action, like ringing a bell with her hand.
“Then Valentina and Adila took a break and went behind a screen that was used to hide the objects, so that Adila could not keep her mind on the demonstration by looking at the object. During the break, Valentina and Adila either played with a ball or practiced a different training activity, for example, Valentina asked Adila to lie down. Or they both relaxed on the lawn and Adila was free to do whatever she wanted—sniff around, bark at people passing by, and so on.
“When the break was over, Valentina walked with her dog back to the original starting position and gave the command 'Do it!'. In a control condition, the ‘Do it!’ command was given by someone other than the owner, who did not know what action had previously been demonstrated by the owner. After the 'Do it!' command, Adila typically performed the action that was previously demonstrated.”
It is remarkable that the dogs were able to do this. But the length of time varied—with an action familiar to the dog, delays were as long as ten minutes. If the action/task was novel and the the dogs had not be exposed to it before, they were still able to perform it after a delay of one minute.
“The authors conclude: "The ability to encode and recall an action after a delay implies that the dogs have a mental representation of the human demonstration. In addition, the ability to imitate a novel action after a delay without previous practice suggests the presence of a specific type of long-term memory in dogs. This would be so-called ‘declarative memory,’ which refers to memories which can be consciously recalled, such as facts or knowledge."
To view more demonstration on the "Do as I do" method, see this, and the following demonstrations.
Fugazza C & Miklósi A (2013). Deferred imitation and declarative memory in domestic dogs. Animal Cognition; DOI 10.1007/s10071-013-0656-5
Dog's Life: Humane
We humans are terrific at measuring and recordkeeping— we even know the length of Noah’s ark, in cubits (300) no less. Technology abets this trait, as computers dutifully crunch our numbers, ad, well, infinitum. As a species, however, we are not so good at appraising information to extract its meaning. Confronted with new data, we tend to overemphasize and generalize, often less than critically.
On that cautionary note, what are we dog people to make of a new University of California, Davis, study that examines relationships between early, late or no spay/neuter and several health conditions in Golden Retrievers? How do we apply its conclusions to the animals in our care?
The Davis docs found increased risk of several cancers, hip dysplasia and cranial cruciate ligament tears among sterilized Goldens; the incidence varied according to the sex and age-at-neuter of their subjects. As such, their findings add to a growing library of veterinary literature on the spay/neuter subject. However, the authors are careful to limit their conclusions, as should we.
First, the findings are breed-specific. Goldens, a highly inbred line, were chosen in part because of their susceptibility to cancers and joint issues. The gene pool was further limited by a study sample of dogs (759, to be precise) seen at the UC Davis clinic, in northern California.
Second, we need to remind ourselves that risk is not destiny, and that correlation is not causation. The study notes that the risk of one type of canine cancer quadrupled in late-neutered females, but also reveals that its incidence grew from 1.6 to 7.4 percent— meaning that about 93 percent of the subjects did not contract the disease.
The authors also indicate that they did not specifically consider obesity, another known factor in dysplasia and cancers. Neutered dogs do tend to be heavier, but we can manage that risk by controlling food intake and quality. We also need to recognize that other studies have noted countervailing positive health effects, as spay/neuter reduces or eliminates rates of other common diseases, such as mammary cancers and uterine infections.
Third, context is crucial. These data feed into the universe of things that are harmful to canines. We know, for example, that nationwide, some 50 percent of the animals in shelters don’t survive the experience. To the extent that intact canines contribute litters to the shelter population, that risk dwarfs exposure to accidents or disease. Shelter “save” rates are improving in many places, but we remain far from a no-kill equilibrium. Job One for canine partisans (including the veterinary community) remains the imperative to reduce that carnage.
After sheltering, risk-of-death varies widely by age and breed. A comprehensive University of Georgia study of vet-reported deaths (“Mortality in North American Dogs from 1984 to 2004,” published in 2011) identifies infections, trauma and birth defects as primary culprits in young dogs, with tumor-related diseases at various breed-specific rates, distantly followed by trauma and infections, which dominate the tally for the late-in-lifespan.
Finally, there are the behavioral and other risk implications of fertility, including management of ardent males and bitches in heat.
The Davis study is a significant contribution to our understanding of the unintended consequences of fertility management in a useful and popular breed. Reproductive organs contribute hormones for many reasons—it would be surprising if their removal were completely trivial. Alternatives to traditional spay/neuter do exist, but they are rarely performed. Injectable sterilizers and contraceptives are coming on the market (they, of course, will carry their own measurable side effects).
It’s important to recognize the limitations of the study: one breed, one gene pool, defined conditions and their rank among all the calamities that can befall our best friends. The study itself notes that spay/neuter is uncommon in Europe, which would appear to open up a range of comparative research possibilities and fertility management options.
We should add the Davis work to the burgeoning database. But until a lot more measurements have been taken from which broader conclusions may be drawn, the best advice is not general to all dogs, but individualized: choose your canine companions carefully and love and support them well, and completely. And recognize that we can’t measure or control for everything, yet—or ever.
Good Dog: Behavior & Training
Deciding when to euthanize
Not everybody is at ease with the idea of euthanasia under any circumstances, and I understand that. Many people have moral conflicts with deciding to end the life of a pet, no matter what the reason. My perspective is that this is a highly individual decision but that I personally am comfortable with euthanizing my pets once their quality of life is so compromised or they are in such pain that keeping them alive feels like it’s more for my sake than for theirs. It’s my view that a peaceful death by euthanasia frees them from pain and misery, and is the final gift of love I am able to provide. I know many disagree, and I’m not suggesting that one way or another is right—I’m just describing my own personal take on this issue.
That doesn’t mean that I haven’t cried buckets and been inconsolable when I’ve euthanized a dog. It’s horrible beyond imagination, and I’ve never really recovered from it in any case. I always hope for any dog (or any person for that matter) to surrender peacefully to death while sleeping. When that doesn’t happen in time, facing the tough decision of when to euthanize is a challenge. Sometimes it’s obvious when it’s time because the dog has reached a point of literally being unable to move, being in constant and unmanageable pain, showing no joy at all or no recognition of anything or anyone.
In other cases, it’s not so clear, which is why a new tool that helps guardians and veterinarians decide when that moment has arrived may be useful. Researchers at Michigan State University developed a survey for probing into the specifics of a dog’s quality of life when undergoing chemotherapy for cancer. The idea is to develop an objective way to assess quality of life, which is such an important consideration when deciding whether to continue life-prolonging measures or to face the possibility that it is time to say good-bye.
Questions address a range of behavioral issues and observations before treatment, a retrospective on the dog’s behavior six months prior, and continued observations throughout their treatment at regular intervals. The questions address aspects of dog behavior including play, measures of happiness, and signs of disease. Both guardians and veterinarians have questions to answer based on their own observations. A small pilot study of 29 dogs found high levels of agreement from clinicians and guardians. Researchers plan to expand their original work to a study with hundreds of dogs and to other illnesses and medical issues as well.
Do you think an objective tool such as this might help you decide when to euthanize a dog, or do you feel comfortable with just “knowing” when that sad day has come?
Good Dog: Behavior & Training
Science supports what we’ve long believed
Our dogs are our kids. It’s not rocket science—we love them, they love us. They look to us for comfort and care. We call them our fur kids or our four-legged children. So, even though it’s not news to us, it’s validating to see science confirm what we already thought was true: Our dogs are like children to us.
Children have been shown to explore the world most confidently if they have a strong attachment to their caregiver (usually a parent.) They use the parent as a secure base from which to explore their environment if they have learned that the parent is dependable and reliable, and this phenomenon is called the secure base effect.
In the recent study, The Importance of the Secure Base Effect for Domestic Dogs—Evidence from a Manipulative Problem-Solving Task, researchers conclude that dogs are bonded to their guardians in the same way that infants are bonded to their parents. They found that dogs use their guardians as a secure base, just as children do.
In the study, dogs were tested in each of two experiments and their behavior was quantified. In the first experiment, dogs were given the opportunity to obtain food from interactive dog toys, and the amount of time the dogs spent attempting to extract the food was recorded. The dogs were tested in three different experimental situations: 1) with their guardian absent, 2) with their guardian present and encouraging them, and 3) with their guardian present but silent and unresponsive. Researchers also recorded how much time the dogs spent in close proximity to their guardians as well as to the experimenter, who was present in all conditions.
The results of this experiment showed that the different situations had an impact on how long the dog manipulated the interactive toy in an attempt to extract the food. The dog manipulated it longer when the guardian was present than absent, but there was no difference in response to whether the guardian was encouraging the dog or remaining silent. The dogs spent an equal amount of time close to their guardian regardless of whether they were receiving encouragement or not. They spent more time close to the experimenter when their guardians were absent than when they were present, suggesting that the experimenter offered some security, social support or comfort in the experimental context.
The second experiment was designed to determine if the effects seen in the first experiment could be explained simply by the fact that in the situations in which the guardians were present, there were two people in the room, whereas in the guardian-absent condition, there was only one person. In other words, what if dogs are not affected by having their guardian as a secure base, but simply react to the presence of more than one person in the room? So, in experiment two, the first experiment was modified to include a fourth condition in which an unfamiliar person (rather than the guardian) was present along with the experimenter.
The results of the second experiment were that dogs manipulated the interactive toy longer in the presence than in the absence of their guardians, regardless of whether an additional unfamiliar person was in the room. The dogs spent more time near their silent, unresponsive guardians than to the unfamiliar person, who also refrained from interacting with the dog. The addition of the unfamiliar person condition allowed the researchers to determine that the guardian had a specific effect on the dog’s performance that cannot be explained by the presence of just any person.
Prior to participating in this experiment, all dogs were tested for their willingness to eat food in the absence of their guardians. They were also scored for their tendency to exhibit separation distress when kept away from their guardians. Interestingly, there was no relationship between the time spent manipulating the toys in the absence of their guardians and the amount of separation distress they showed, which means that the results of the experiments cannot be explained by a tendency of the dogs to manipulate the toy less because of the distress of separation.
This is the first study to demonstrate that the relationship between dogs and guardians is similar to the relationship between children and their parents in that both involve the secure base effect. This raises concerns about experiments into cognitive abilities that involve problem solving that is far more complex than in this study because the absence of guardians could significantly lower performance by the dogs.
It also confirms the view that most of us have about the canine members of our family—they are like kids to us!
Good Dog: Behavior & Training
Studies now suggest that personality in non-human animals can be measured and evaluated, just as in humans.
All dogs are the same. really. Look at an evolutionary tree and you’ll find all domestic dogs, clustered together in one spot. But that can’t be the entire story. When asked, Rachel Licker of Lawrenceville, N.J., describes Piper, her “Basset Hound on stilts,” as incredibly goofy, communicative, playful and quick to overwhelm. According to Mary de Vachon of Nice, France, Ria, her Sheltie, is gentle and loving, content and confident, extremely shy, and above all else, a mademoiselle.
While all dogs might fit in the same spot on the tree of life, each has his or her own unique personality. Just as one person might greet you with a cautious wave or a coy smile, another will come barreling into your life doling out hugs and kisses. Dogs are the same, in that each is different.
WHAT IS PERSONALITY?
Additionally, the word describes an individual’s usual pattern of behavior, characteristics that are relatively stable over time and across situations. Say a snowman with stick arms that wave in the wind appears on the front lawn after a snowstorm. Some dogs would walk by as though Frosty had always been there. Others might play-bow and dance joyfully in front of their new friend, while a few are sure to freeze, tuck and retreat.
If those same dogs then confront other novel situations—balloons in a tree, a parade, clowns jumping out of a car, you name it—those who perceived Frosty as no bother would probably continue to be indifferent, while those who equated Frosty with Satan would also be likely to associate other odd events with the underworld. Although it does not imply that an individual will respond the same exact way every time (dogs are not robots, after all), the term “personality” denotes an individual’s usual perceptions or interactions.
Thinking about personality gets tricky very quickly because there is no universal definition. Some fields distinguish between personality and temperament, while others use the terms interchangeably. As Samuel Gosling, PhD, a personality and social psychologist at the University of Texas, Austin, explains, “Temperament is the basic, biologically inherited tendencies of an individual, and personality is the result of the interaction between temperament and the environment.” That distinction is common in human psychology but is not always made in animal fields. But, as Gosling adds, “since adult animals are a combination of biologically inherited tendencies as well as individual experiences, it seems to me misleading to call that temperament. In humans, we would call that personality, so why not in other animals?”
Making a distinction between temperament and personality could enable researchers to explore whether certain traits are more stable over time than others. For example, a recent analysis surveying a number of studies found that in puppies, aggression and submissiveness were most consistent, while responsiveness to training, sociability and fearfulness were least consistent.
Understanding the relationship between early-life temperaments and later-in-life personalities could be paramount for real-world issues, such as selecting dogs for work or companionship. For working dogs, Gosling and his team advise the U.S. Department of Homeland Security on how to measure personality-trait consistency in order to improve the selection and training of working detector dogs.
Back home, you might think you have a handle on who your puppy Wizzer is, but what you’re seeing might or might not relate to Wizzer’s adult personality. (So even if Wizzer starts out apprehensive about the vacuum cleaner, there’s hope for improvement, and you can help him.)
At the same time, many shy away from using the term when it comes to non-human animals, sometimes because they’re uneasy about the “A” word: anthropomorphism. To avoid linking dogs and personhood so explicitly, scientists use alternative descriptors such as “behavioral types,” “behavioral syndromes” and “coping styles.” Regardless of the word employed, when the definitions are compared, they tend to describe the same basic phenomenon: consistent, individual differences in behavioral tendencies over time and across situations.
Much of the initial pushback against the term “personality” has dissipated because studies now suggest that personality in non-human animals can be measured and evaluated, just as in humans. (Relatively speaking, this field is in its infancy, and techniques and methodologies continue to evolve, so stay tuned.)
HOW IS PERSONALITY EVALUATED?
Questionnaires, however, are not bulletproof. Gosling notes that questionnaires “don’t rule out the possibility that ratings are based on some stereotype, say a physical stereotype, like ‘bigger animals are more aggressive.’ You could still get those biases.” Dogs’ physical appearances are emotion points for humans and make them susceptible to attributions and judgments that might have no bearing on the personality of individuals. For example, the Papillon breed standard specifies that these small dogs are to be “happy, alert and friendly,” and their physical appearance easily promotes this perception of an overall perkiness. But on an individual basis, just like other dogs, Papillons can be shy (or downright neurotic).
Even taking into account the risk of stereotyping, questionnaires provide meaningful information about canine personality. When comparing questionnaire ratings with separate behaviorobservation assessments, a strong link has been found. So if a dog is judged on a questionnaire to be highly timid, independent observers will generally also describe the dog’s behavior in terms consistent with shyness.
Since people are rarely shy about discussing their dogs, collecting data via questionnaires can be incredibly fruitful. The Canine Behavioral Assessment and Research Questionnaire (C-BARQ), developed by James Serpell, PhD, and researchers at the University of Pennsylvania, is a widely used assessment of dog behavioral characteristics (available for public use). The 101 questions gather insights into dogs by asking owners to use a five-point scale to describe how their dog would likely react in a variety of different situations, such as anxiety or fear in heavy traffic or when examined by a veterinarian; excited when the doorbell rings or when visitors arrive; and of course, likely to chase cats if given the opportunity.
A recent study of former breeding dogs from commercial breeding operations— commonly referred to as “puppy mills”—relied on the C-BARQ to evaluate the dispositions of these dogs once they’re out in the world. Overall, they were found to be more fearful and nervous than typical pet dogs, particularly regarding strangers and stairs, and many were sensitive about being touched. Despite having lived for years in their adoptive households, many of these dogs still displayed persistent fear and anxiety, which is exactly the type of long-term rather than short-term tendencies that investigations of personality aim to reveal.
But do we really need questionnaires when a dog’s actual behavior is right in front of us? Of course, it’s easy to watch a dog and write down how he or she reacts to various stimuli, but that’s not necessarily enough. While it is plausible to observe dog behavior in myriad situations by simply waiting for different scenarios—such as flashing lights and loud sirens—to present themselves, test batteries, which are designed to investigate whether various stimuli and situations elicit particular responses, are more common. For example, the Dog Mentality Assessment (DMA) is a behavior test originating in Sweden that requires dogs to respond to, among other things, novel people, furry objects, loud noises, the potential for play and people dressed up like ghosts (yep, ghosts).
The researchers boiled down dogs’ behavioral responses into five personality dimensions: sociability, playfulness, chase-proneness, aggressiveness, and curiosity/fearfulness. Comparing the results from the DMA test battery with the C-BARQ assessment showed broad agreement between the two.
You can think of these personality dimensions as the canine equivalent of the classic human “Big Five” personality models: extroversion (sociable and outgoing), agreeableness (trustworthy and straightforward), neuroticism (anxious, irritable and shy), openness (curious, imaginative and excitable) and conscientiousness (efficient, thorough and not lazy). Research groups continue to flesh out the various personality dimensions found in dogs; recently, the Anthrozoology Research Group in Australia generated a slightly different list of attributes, one that included extroversion, neuroticism, motivation, training focus and amicability.
As you might imagine, it’s not easy to summarize and sort all of a dog’s behaviors into a small number of buckets, so there is much left to learn in this area. One hot topic that warrants more research is the possible relationships between different traits. For example, are individuals who are more bold also more sociable and playful with strangers? Or is it more challenging to find links between traits? While boldness and aggression correlate in some species, researchers have not found that to be true for dogs. Dogs who were bolder were not necessarily more aggressive. The possibilities for this area of research are virtually endless.
WHO WILL MY DOG BE?
The short answer to “Who will my dog be?” is “Wait and see.” Current research finds that puppy tests have low predictive value for later-in-life behavior. On the other hand, personalities examined in older dogs do display more stability over time. Krista Macpherson, a PhD candidate at the University of Western Ontario who studies cognitive abilities in domestic dogs, reminds us that at the time of testing, puppies have had minimal interaction with the outside world, apart from their conspecifics. “At eight weeks, they are not that developed cognitively, and there are a lot of experiences yet to be had,” she observes. Researchers at the Clever Dog Lab (part of Austria’s University of Vienna) are currently investigating whether early temperament tests are predictive of behavioral tendencies in an older dog. By testing dogs at a range of ages, they will be able to explore the predictive value of early-life temperament tests.
At the end of the day, Jules Winnfield, the gangster from Pulp Fiction, gets it right: “A dog’s got personality, and personality goes a long way.” Rachel Licker, who lives with Piper, reminds us exactly why personality is so important. “I hope people really enjoy their dogs being more than just amicable, and give their dogs more leeway to be multi-dimensional beings. I think they might enjoy their dogs more, and I think it would create more space for the dog and owner to be happy together.”
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.”
Copyright © 1997-2016 The Bark, Inc. Dog Is My Co-Pilot® is a registered trademark of The Bark, Inc