Good Dog: Studies & Research
The influence of each species’ feeding ecology
Humans tend to be risk-averse, which is often illustrated by our decision when offered either $100 or the opportunity for a 50-50 shot at receiving either $200 or nothing. In general, humans go for the sure thing. We are not, as a species, risk-prone, or we would gamble on the shot at getting the bigger payoff.
It turns out that a number of studies across a broad range of species have shown that how a species responds to risk is predictable based on their feeding ecology. Animals who depend on erratic, ephemeral food sources, such as meat that they hunt or fruits that are patchy and only ripe for a brief time, tend to be risk-prone. They are willing to gamble on the big payoff. Species that eat diverse types of food or food that is more reliably available, such as vegetation, are risk-averse.
Some of our primate relatives are like us, and some are the opposite. For example, bonobos and lemurs (who both eat a very diverse diet that is mainly vegetarian) are risk-averse like us, choosing a sure thing of lower value over a chance at something better. Chimpanzees and capuchin monkeys—both meat and patchy fruit eaters—are different, being risk-prone and choosing the option that may yield a big reward but could leave then empty-handed. This pattern has appeared in closely-related species birds, too, where those who eat insects are risk-prone, while species who eat seeds are risk-averse.
Scientists haven’t fully explored how widespread this pattern of feeding ecology predicting risk-taking behavior is, but wolves and dogs are an interesting test case. These two species diverged quite recently in an evolutionary sense, but their feeding ecologies differ greatly. Wolves are primarily hunters and dogs are mainly scavengers. Hunting has a high failure rate, but the rewards of a big kill are enormous. In contrast, the source of food for the vast majority of dogs worldwide is human refuse, which tends to be available far more regularly.
In a recent study called “Exploring Differences in Dogs’ and Wolves’ Preference for Risk in a Foraging Task” scientists investigated whether wolves and dogs conform to the pattern seen across so many other species. Based on their different feeding ecologies, they predicted that compared with each other, wolves would be risk-prone and dogs would be risk-averse. The study was done at Wolf Science Centre in Austria, using dogs and wolves who were raised and live at the facility and have had the same overall experiences there.
The subjects of the study were trained to choose either a bowl that contained a dry pellet of food or a bowl that had a fifty percent chance of containing a piece of meat and a fifty percent chance of holding a stone. After each choice, the subject was given the contents of the bowl. All the wolves and dogs in the study were subject to tests to confirm that they understood the choice they were making and also to confirm that they preferred the meat to the dry food pellet.
The researchers found that the pattern of risk-taking seen in other species also applied to wolves and dogs. As expected, wolves were more risk-prone than dogs. However, there is more to this study than that simple conclusion. Wolves learned the system faster than the dogs, and the researchers acknowledge that they may have understood it better than the dogs. Additionally, dogs’ preference for the meat versus dry food pellet was not as strong as it was for wolves. Therefore, the risk of losing out and getting nothing for the chance to get something only a little better than a food pellet may not have been worth it to dogs. There was greater variation among individual dogs in risk-taking strategy compared with wolves, who were more similar in their choices, so it’s possible that there are dogs who are risk-prone as well as dogs who are risk-averse. (Dogs made the risky choice from 38 to 76 percent of the time, while wolves took the risky option 70 to 95 percent of the time.)
Overall, despite the conclusions made from the data in this study, direct comparisons of the choices made by these two species may require further study. It would be very interesting to learn more about decisions to take risks by dogs and wolves in a study with more than seven of each species, though I realize possible subjects for a study such as this are limited. It would also be fascinating to know about the decisions foxes and coyotes would make if presented with the same choices. Comparative research that include dogs as one species among many allow us to learn a great deal about how their evolutionary history and ecology have affected their behavior. It’s one of many ways that we can deepen our understanding of the animals who share our homes and live in our hearts.
Are We Smart Enough to Know How Smart Animals Are?
In Are We Smart Enough to Know How Smart Animals Are? Frans de Waal presents a fascinating history of the study of animal behavior and cognition. De Waal, who says his love of animals dates to his childhood, is a worldrenowned primatologist and ethologist and director of the Living Links Center at the Yerkes National Primate Research Center. We asked him to shift gears and give us his take on the canine mind.
Bark: Konrad Lorenz (co-founder of your field) wrote Man Meets Dog in 1954. And while it is still one of the best, if slightly flawed, books on canine behavior, why did it take so long for ethologists, and other researchers, to to study dog behavior?
Frans de Waal: Dogs were (and are) considered imperfect subjects of study because they are “unnatural.” Many ethologists, including Lorenz, feel that natural behavior under naturalistic conditions is what we should focus on, and the dog is a product of artificial breeding. Lorenz liked all animals, however, and so couldn’t resist describing his dog stories, and we should all be grateful.
Clearly, the dog is a mammal with many typical mammalian tendencies, so now scientists are finally seeing that the fact that they are domesticated also has advantages. For example, they are eager to work with us, they are generally not dangerous, they are smart, they have empathy. Lots of great things can be done with them. And they are easier to work with than other large mammals, such as apes and dolphins.
Bk: Can you give an example of how other species, including dogs, demonstrate empathy?
FdW: American psychologist Carolyn Zahn-Waxler sought to determine at what age children begin to comfort family members who sobbed or cried “ouch.” It turns out that children do so at one year of age. In the same study, Zahn-Waxler accidentally discovered that household dogs react similarly. Appearing as upset as the children by the distress-faking family members, the dogs hovered over them, putting their heads in their laps with what looked like great concern. This work has recently been repeated in different studies, more focused on the dogs themselves, and it is clear that these animals show empathic concern for humans.
The ancestor of the dog, the wolf, probably behaves the same. If “man is wolf to man,” as Thomas Hobbes liked to say, we should take this in the best possible way, including a tendency to comfort the whimpering and help the needy. This insight, of course, would undermine much of political philosophy based on Hobbes’ dog-eat-dog view of nature.
Bk: Do you think human bias has played a part in some of the canine cognitive studies?
FdW: At first, dogs were rated as more intelligent than even apes and wolves because they followed the direction of human pointing (at a bucket with food), whereas apes and wolves ignored human directions. Then it was found that wolves raised in a human home will act more like dogs, following human pointing, suggesting that the earlier failures with wolves were probably due to lack of bonding and attention. The same probably applies to the apes. Now, dogs are seen not just as smart but rather, as finely in tune with the species that bred them.
They have a special bond with us, as also reflected in the oxytocin studies, which show that human-dog contact increases this “cuddle” hormone in both. The dog is perhaps the only animal that performs at its peak when tested by humans, whereas many other animals are not so into us, hence need to be tested in different ways. This is yet more proof that cognitive testing of animals always needs to take into account what kind of animal we are dealing with: we need to find the most species-appropriate way.
Bk: In contrast to behaviorism’s reward/ punishment model, ethology views animals as “seeking, wanting and striving.” Why do you feel the latter is a more productive way to look at animals?
FdW: The behaviorists (followers of B. F. Skinner) totally overlooked natural animal tendencies. Trying to explain all behavior on the basis of reward and punishment, they could not explain why you can train a dog to fetch, but not a rabbit or a goat.
Predators are obsessed with small moving objects, which we see every day in our dogs as well as cats. Their interest sets up a learning situation where they are going to absorb many lessons about how to catch these moving objects, how to trick them, how to outsmart them. Dogs eagerly learn all of those things.
Reward and punishment are only small parts of the story; their natural hunting instinct is, in fact, the driver of the process. This is where behaviorism failed. It had some good ideas, many of them applicable to animal training, but its perspective was far too narrow as it lacked attention to natural tendencies and the evolution of behavior.
Bk: Why do you think Darwin used dogs to illustrate emotional continuity?
FdW: Darwin was a dog lover, and he knew that to get his message across about the continuity between human and animal emotions, the dog would be the easiest way to communicate. Darwin mostly worked on the expression of emotions (it’s hard to know what animals feel, but we can at least document how they signal various states, such as fear, submission, anger, affection). Of course, the dog is very expressive with its postures, facial expressions, tail-wagging, growling and so on. Darwin knew that most people could relate to all of this, and would have more trouble if he described other species that people have less exposure to.
Bk: In terms of an evolutionary advantage, how important is it for a species to have self-awareness, or theory of mind?
FdW: These capacities require large brains. In terms of recognizing oneself in the mirror or understanding what others know, the champion species are apes, dolphins, elephants and perhaps also the corvids (crow family). This doesn’t mean that dogs lack them. They probably have similar understanding, but not as fully expressed.
The more complex the societies of a species, the more demands there are on cognition, and perhaps canines do not need social understanding at the level of an ape or dolphin. I feel we need to judge animals on what they are good at and what they need to know to survive. In this regard, canines have lots of specialized skills, often related to their sense of smell, their pursuit of prey, their need for tight cooperation and so on. This is where we should test them out, and probably find remarkable skills.
Bk: Clearly, emotions are important to the understanding of behavior; how do they relate to and inform one another?
FdW: In my book, I left emotions out on purpose because I felt it would muddle things. But there can be no studies of cognition without attention to the emotions, and vice versa. The two go hand in hand. In our famous capuchin monkey experiment with the grape and the cucumber, for example, you can see not only that the monkeys judge what they get relative to what others get, but also their strong emotional response. You cannot study the one and ignore the other.
The Vital Role of Dogs in the Search for Cancer Cures.
Bev Thompson: How challenging was it to separate from the loss of your sister in order to write Heal? What kept you going?
Arlene Weintraub: Well, not challenging at all, but quite motivating. For example, I learned about a drug for gastric cancer that was first tried with dogs with a particular genetic mutation; it was one of the first targeted drugs for cancer. Basil the Golden Retriever had his life extended by eight years, which, for a dog, is a lifetime. This cure inspired me to continue researching.
BT: How many dogs are in dog cancer trials, as opposed to human cancer trials?
AW: It’s case-by-case in these trials. One advantage is that animal trials don’t require thousands of patients. Just a couple of hundred are needed to get a drug approved.
BT: How can we find a reputable cancer trial?
AW: The way to find cancer trials for pets that translate to therapies that might help people is to contact vet schools. Many are leading a lot of the trials in comparative oncology. Also the Comparative Oncology Trials Consortium (COTC) is a source listed in the book.
BT: When should a companion animal owner pursue radical but potentially life-saving treatment?
AW: Standards are much stricter in veterinary than human medicine. Vets are very clear that if dogs are unhappy in the trial and the drugs have serious side effects, they will be taken out of the trial. Their duty to the pet is making them better—that’s the vow they take as veterinarians.
BT: What was your most surprising research finding?
AW: I can’t think of only one. Cancer research has advanced tremendously since the book was published. The thing I remember most was how grateful the dog owners were to enroll in these trials. Many owners were looking at nothing but euthanasia and were grateful to have extra time with their pets.
BT: I know that one of your favorite stories is “Cali’s Total Mastectomy” in chapter six. Why is this so meaningful to you?
AW: I was able to meet the dog who was cured and her owner, a breast cancer survivor. Both suffered the same disease and were cured. The University of Pennsylvania is taking dogs from shelters with mammary tumors and adopting them out to families. They are trying to learn what makes benign tumors turn metastatic by looking at tumors in various stages in the same dog. Some of their findings have recently been published.
BT: Do you think we will push beyond traditional medical protocol and let a dog’s nose nudge us closer to detecting cancer cells by scent even before symptoms show up?
AW: There is more interest in the idea of figuring out what dogs are detecting in the early stages of cancer, and then translating that into a breath-a-lizer or an electronic nose for use in an annual physical—devices that can be developed for lung, ovarian and gastrointestinal cancers. Any cancer-detection method —dogs or devices—must be close to 100 percent accurate. False negatives are a challenge for early detection.
BT: Coming full circle, did you find that you were able to heal by penning Heal?
AW: I had pretty much lost my faith in science with the death of my sister. I didn’t think anything would work. No new ideas. Then I came to the realization that there are scientists out there exploring innovative scientific leads. New ideas from [the study of] dogs can offer tremendous benefits to the search for cancer cures.
Good Dog: Studies & Research
What you say and how you say it both matter
Humans use both words and the intonation of speech to decipher the meaning of language, and it turns out that our dogs do, too. In a research paper called “Neural mechanisms for lexical processing in dogs” scientists investigated how dogs process the meaning of language. They found that dogs’ brains have even more in common with humans’ brains than previously thought. (It’s not clear when we will collectively stop being surprised by this, but I hope we always remain excited about new evidence to explain why we feel that dogs are kindred spirits.)
In this study, dogs who have been trained to remain still while their brain activity is recorded listened to recordings of their trainers talking. There were four types of recordings: 1) words of praise spoken with intonation typically associated with praise, 2) words of praise spoken with a neutral intonation, 3) neutral words spoken with intonation typically associated with praise, and 4) neutral words spoken with a neutral intonation.
Researchers analyzed the brain activity of the dogs in response to each of the recordings, and came to several conclusions about the way that dogs respond to words and the intonation of human speech. The dogs processed the vocabulary in the left hemisphere of their brains, which is where humans also process the meaning of words. The dogs processed the intonation of the words separately, in a different region of the brain. Just as humans do, dogs processed the intonation of human speech in the right hemisphere of their brain. Dogs also process sounds that convey emotion without words in this same region of the brain’s right hemisphere.
Dogs process both words and the intonation of human speech to decipher meaning. Just as humans do, they process these two aspects of speech separately, then integrate them to determine the full meaning of what was said. Only the praise that was spoken like praise—higher pitched than normal speech and with more variation in pitch—activated the reward centers of dogs’ brains. Though they may understand words of praise said in any manner, it only makes dogs happy to hear us praise them when we do it with proper feeling.
This research does more than reveal yet another similarity in the way that human and dog brains process information. It also suggests that the ability to connect a word to a meaning did not develop with the evolution of spoken language. Rather, it is a more ancient ability that can be made use of in the context of the human-dog relationship to link specific sounds to specific meanings.
The take away messages from this research are that dogs process two parts of spoken language—words and intonation—the same way that humans do and if you want to make your dogs happy, you have to praise them like you mean it!
Good Dog: Studies & Research
Individual variation explains a lot
Dogs are well known to be chowhounds. The idea that they love food more than anything else is practically (excuse the expression) dogma in the fields of canine behavior and dog training. The trouble is, recent research suggests that it is not true for all dogs.
In a study called “Awake Canine fMRI Predicts Dogs’ Preference for Praise Versus Food” scientists investigated whether dogs prefer treats or praise, and whether their choice can be predicted by their brains’ response to both stimuli. In one experiment, they measured the level of activation of the brain’s ventral caudate, an area known to function as a reward center, in response to items that predicted various outcomes. A toy car predicted that verbal praise was coming, a toy horse predicted that food on its way and a hairbrush was associated with nothing. Dogs were trained to make these associations with a series of 40 pairings of each object with what it predicted. The activation of the specific region of the brain was measured with functional Magnetic Resonance Imaging (fMRI), which is possible because the dogs in the study have all been trained to remain motionless while in the scanner.
The average activation of the reward center of the brain was higher in the food and praise conditions than in the neutral condition, which shows that the dogs did learn the associations between the objects and what the objects predicted. (Each dog’s responses in the brain to seeing the toy horse and NOT receiving the expected praise was also measured.) There were 15 dogs in this experiment, and most of them had a similar response in the reward center to the food or to the praise. Four showed a stronger response to praise and two showed a stronger response to food. The average response to praise and to food did not differ.
In another experiment, dogs were placed in a Y-maze and given the opportunity to choose which arm of the maze to go to. One arm led to a food bowl with treats and the other arm led to the dog’s guardian, who provided petting and praise. Each dog was tested in the Y-maze 20 times. Seven dogs in the study chose the guardian the more times than the food, and seven dogs chose the food more often. One dog chose the guardian and the food an equal number of times.
The relative value of praise versus food in the first experiment was highly predictive of the choices that dogs made in the Y-maze experiment. Dogs whose ventral caudate showed a strong response to praise were more likely to choose their guardian over food but dogs who did not show such a strong response to praise relative to food were more likely to head for the food when given a choice.
Regrettably, the results of this study have erroneously been reported in many places as proof that dogs prefer praise and belly rubs to treats, and suggested that using treats in training is therefore unnecessary. It has been written in many places discussing this study that 13 of 15 dogs prefer praise to food, and that’s not correct. What the researchers actually wrote is that in 13 of the 15 dogs, the ventral caudate showed either roughly equal activation to food and to praise or greater activation to praise than to food.
It’s quite interesting that roughly half of the dogs chose their guardian over food. For those dogs, social interaction such as praise and belly rubs may be more effective than treats in training. However, caution is important when acting on the findings in this study because the research may overestimate the response of dogs to their guardians relative to food in situations outside the laboratory setting.
The lab may have been stressful, causing a bias in dogs towards an increased interest in their guardians when compared with food. They may have been seeking comfort from their guardians in a way that they might not be during typical training situations. The scientists do point out that these dogs have been trained to stay still in the scanner and that the lab is a familiar environment. That does not mean the dogs are as comfortable as they are at home or in other areas such as on neighborhood walks, at the park or at the training center where they attend classes. It’s important to know what dogs choose in the actual training setting before changing what reinforcement to use based on lab research.
Additionally, although dogs may value social connections over food when the social interaction is with their guardian, not all training occurs between guardian and pet. I do a lot of training with dogs who I adore, but I don’t share quite the same bond with them as they do with their own guardian. So, just because dogs may prefer affection from their guardian over food does not mean that they prefer affection from just anyone over food. Finally, in many training scenarios, dogs receive praise in addition to food during training, and that may be more effective than either one alone.
Many people swear that their dogs prefer praise and petting to treats, and others are just as certain that food wins out every time with their dogs. Perhaps the most important lesson from this study is that individual variation in preferences is huge. If you feel strongly about what matters most to dogs, there’s a good chance you’re right—when it comes to your dog, anyway.
Do you think your dog would go for food or for praise and affection if given the choice?
News: Guest Posts
Not surprisingly, a study published July 29, 2016 found that the English Bulldog no longer retains enough genetic diversity to correct life-threatening physical and genomic abnormalities. This means breeders cannot use the established population of purebred dogs to reverse the trend in extreme and painful exaggerations such as crippling dwarfism and respiratory deformities - traits that uninformed pet-owners find appealing.
In the early 1800s Bulldogs were trained for bull-baiting, a particularly cruel and vicious sport. In 1835 the Royal Society for the Prevention of Cruelty to Animals convinced Parliament to enact the first animal cruelty law for the protection of domestic animals, including outlawing bull baiting.
As such, the Bulldog had outlived its usefulness. Like the pre-19th century Wolfhound that disappeared with the eradication of wolves in the British Isles, and the Tumbler whose demise was the invention of hunting firearms, the Bulldog was destined for extinction.
English Bulldog from 1890
But it was not to be. Beginning about 1840, the Victorian dog fancy's unabashed sentimentality was a catalyst for saving even the most formidable working breeds from their inevitable demise. Like many others, such as the Dachshund and Mastiff, Bulldogs went from working hard to hardly working.
Utility dogs were "refined" and transformed to fill jobs they weren't originally bred for - as show dogs and companions. Altered physical and behavior characteristics along with decreased levels of aggression were more compatible for their augmented duties as house pets.
English Bulldogs from 1920s
Beginning in the late 1890s, Bulldog breeders (and other breeders as well) selected small groups of genes from a diverse genome and created new breed-types. They were in effect increasing the odds that genetic anomalies would more likely be expressed to bring out exaggerated traits, like the Bulldog's baby-like face, corkscrew tail and affable personality.
As "desirable" aesthetic traits were selected for, other genetic variants including beneficial genes that contribute to overall health were eliminated from the gene pool, never to be reclaimed.
In the last few decades the most exaggerated traits in the Bulldog - the extreme brachycephalic skull and deformed skeleton- have become increasingly pronounced because naive consumers want that type of dog and consequently that's what many breeders select for.
Driven by economics, fashion, and uninformed decisions, breeders and buyers either ignore or are unaware of the genetic problems that have spread throughout the population.
The demise of the breed may not be a good thing for Bulldog-lovers, but it will thankfully put an end to the malformed and painfully crippled modern Bulldog we recognize today.
The good news is that some breeders are intent on bringing back the "Olde-Fashioned-Bulldogge".
News: Guest Posts
Reason number I’ve-lost-count that dogs are better than pretty much everything else: They’re sniffing out health disasters waiting to happen — and once again proving they are true lifesavers.
Studies out of Cambridge University and the University of Oxford have revealed new findings about a chemical called isoprene. It seems levels of isoprene rise when blood sugar levels fall, and its scent can be detected by dogs on human breath. Which is excellent news for Type 1 diabetics and for parents of children with diabetes.
Diabetics are particularly susceptible to experiencing life-threateningly low levels of blood sugar while they sleep. But Diabetic Alert Dogs, as they’re called, are trained to watch over diabetic kids during the night. If a dog detects the smell of isoprene, she’ll first try to wake the child. If there’s no response, the dog is trained to then go alert the parents.
According to a report in the Endocrinology Advisor, the new role for humans’ best friend is proving incredibly valuable: “Diabetic alert dog owners as a whole have expressed high satisfaction and confidence in their canine guardians.”
So now, in addition to lowering blood pressure and sniffing out certain types of cancer, preventing hypoglycemic episodes can be added to the list of dogs’ health-preserving abilities. Indeed, their noses remain a step ahead of science. Pretty amazing for a species who asks for so little from their human partners.
Good Dog: Behavior & Training
Differential use of the left and right nostril
The common wisdom that dogs can smell fear doesn’t give dogs full credit to the nuances of their ability to sense emotion through their noses. A recent study titled “The dog nose “KNOWS” fear: Asymmetric nostril use during sniffing at canine and human emotional stimuli” examined dogs’ tendencies to sniff various substances with the right or the left nostril. Exploring this side bias may seem like looking at random details, but the side of the nose used to sniff something tells us a lot about the dog’s emotional reaction to the odor. The use of one side of the body indicates a differential use of one side of the brain or the other, which is a clue to the dog’s emotions.
The left side of the brain processes more positive emotions such as happiness and excitement as well as stimuli that are familiar. The right side of the brain tends to take over when a dog is processing negative emotions such as sadness or fear as well as novel stimuli. In general, the right side of the body is controlled by the left hemisphere of the brain and vice versa. However, the nose is an exception; the right nostril sends information to the right side of the brain to be processed and the left nostril sends its information to the left side. The findings of this study suggest that the pathways used to process various olfactory stimuli are dependent on more than just whether they elicit negative or positive feelings.
Eight odors were tested—four from dogs and four from humans. The four human odors were collected as sweat from donors who were joyful, fearful, physically stressed, or in a neutral situation. The joyful and fearful states were elicited by movies, and the physical stress odor was collected after donors ran for 15-minutes. The four canine odors were collected from dogs who were happy following a play session with the guardian, stressed by isolation in an unfamiliar place, disturbed by a stranger approaching the car, and dogs who were asleep. The dogs who “donated” odors were different from the dogs whose sniffing behavior was studied.
To further explore the phenomenon of side bias in sniffing, the guardians of the dogs in the study filled out a questionnaire related to each dog’s temperament. During the study, dogs were led to a video camera under which was mounted a Q-tip saturated with various odors. The videos captured the dog’s sniffing behavior so that it was possible to determine a laterality index for each dog for every odor based on the amount of time spent sniffing with each nostril. A laterality index of 1.0 indicated exclusive use of the left nostril and negative 1.0 indicated exclusive use of the right nostril. Dogs’ cardiac activity was also recorded during the tests of each odor.
I’m sure it’s the science geek in me, but I got a kick out of reading the sentence, “Results for nostril use are shown in Figure 2.” Three of the odors elicited consistent sidedness in nostril use and five of them did not. Dogs more frequently used the right nostril to sniff the canine isolation odor. They more frequently used the left nostril to sniff the human fear odor and the odor from human physical stress.
There were two ways in which the results of the questionnaire were correlated with the laterality pattern for a particular odor. The higher a guardian ranked the dog’s fear/aggressiveness to other dogs, the more likely that dog was to use the right nostril for sniffing the disturbed canine odor. This suggests that individual differences in emotional arousal and perhaps even in temperament influence asymmetries in sniffing behavior. Dogs with higher scores for predatory behavior used the left nostril more for sniffing the odor that came from physically stressed humans. This makes sense when we consider that it is structures in the left side of dogs’ brains that are involved in predatory behavior.
Dogs’ brains are every bit as amazing as their noses, as research about both of them reveal!
Good Dog: Behavior & Training
Natural detection task is very revealing
We all know that Beagles have better noses than Whippets, right? This almost seems too obvious to point out, especially to anyone who has ever had a dog of either breed. However, the authors of a recent study claim to be the first to scientifically document a difference in olfactory abilities across groups of dogs.
The researchers compared scenting ability across four groups of canines: dog breeds that have been selected for scenting abilities, dog breeds that have not been selected for scenting abilities, short-nosed dogs and hand-reared wolves. The task asked of these animals was simple—find the raw meat in a container that is hidden underneath one of five pots. There were multiple tests that varied in difficulty based on the number of holes in the container’s lid.
The results of the study were that dogs bred for scenting ability performed better than both short-nosed dogs and dogs who were not bred for their olfactory capabilities. The short-nosed dogs performed worse than any other group, suggesting that breeding for this head and face shape has adversely affected olfaction. In the most difficult of the tests, only wolves and the dogs bred for scenting abilities performed better than what would be expected if the animals were just guessing. Wolves improved their performance when they were re-tested, but the dogs in all three groups were no better the second time around.
Since dogs did not improve with repeated testing, this test may be a useful one-and-done way to assess a dog’s scenting capabilities. That is important because there is currently no standard method for testing the olfactory ability of dogs, but the method in this study could be used for quick assessments of dogs’ abilities. Most ways of testing dogs involve a match-to-sample design, which means that the dogs are taught a scent and they then have to find the same scent from among a group of scents. That requires extensive training, so it is impossible to determine to what degree those tests are assessing trainability and to what extent they measure scenting ability. Both trainability and olfactory ability are important for success as a working detection dog, but there’s great value in evaluating each trait independently.
News: Guest Posts
An international group of scientists proposes dual domestication from wolves.
Among the many hotly debated topics related to the appearance of dogs in the lives of humans is how often and where it first occurred. In their landmark 1997 paper on dog origins, Robert K. Wayne, Carles Vilá, and their colleagues made the case for multiple origins, but many other students of dog evolution, including Peter Savolainen, a co-author on that paper, have repeatedly and strongly argued for a single place of origin.
In this week’s Science magazine (June 3, 2016) [the article is available here, gratis], Laurent Frantz of Oxford University’s ancient dog program, writing for more than a score of his colleagues from institutions around the world, presents the case for dual domestication of Paleolithic wolves in Western Eurasia and Eastern Asia. According to this hypothesis, a now extinct ancestral wolf split into at least two genetically distinct populations on opposite sides of the Eurasian continent where they encountered and joined forces with humans to become dogs.
Frantz and his coauthors pin much of their argument on analysis and comparison of the fully sequenced genome of a 4,800- year old dog unearthed at Newgrange, Ireland, to other ancient and modern dogs and modern wolves. They found it retained “a degree of ancestry” different from modern dogs or modern wolves. Using that and other evidence the researchers argue that the most comprehensive model for the appearance of the dog involves at least two domestication events 15,000 or more years ago. Frantz writes: “The eastern dog population then dispersed westward alongside humans at some point between 6,400 and 14,000 years ago, into Western Europe (10,11, 20), where they partially replaced an indigenous Paleolithic dog population. Our hypothesis reconciles previous studies that have suggested that domestic dogs originated either in East Asia (9, 19) or in Europe (7).”
I asked Greger Larson, co-director of the Oxford project and corresponding author on the paper, just what were the boundaries of “Western Eurasia,” comprised apparently of Europe and the Middle East, and “Eastern Asia?” He answered in an email that the boundaries were left deliberately vague because where wolves became dogs remains unknown, like the date itself.
In Science, Frantz writes: [W]e calculated the divergence time between two modern Russian wolves used in the study and the modern dogs to be 60,000 to 20,000 years ago.” The first number puts the dog in the time when Neanderthal was still the big kid on the European block, raising the possibility that Neanderthal had protodogs or that early modern humans came to Europe with dogs or soon allied with wolves. Either of the first two prospects must have set off alarms in some circles for Frantz cautions that those dates should not be taken as “a time frame for domestication” because the wolves they used may not have been “closely related to the population(s) that gave rise to dogs.”
Fundamentally, this paper is at once a bold attempt to come up with a workable hypothesis to explain the appearance of the dog in human affairs and a tentative step into troubled waters. Left unanswered are virtually all outstanding questions regarding the who, what, when, where, and why of the transformation of wolves to dogs. Geographically all it does is exclude Central Asia. Whether it does so wrongly may depend on how you define Central Asia geographically.
What makes it bold and radical even is the suggestion that early humans and wolves could have gotten together wherever and whenever they met on the trail of the big game they were following. There are many reasons for that including similar social and familial cultures, but humans and wolves could have joined forces to have become more successful hunters. We learn from Wolves on the Hunt: The Behavior of Wolves Hunting Prey by L. David Mech, Douglas W. Smith, and Daniel R. MacNulty (Chicago, 2016) that while wolves appear excellent at finding and trailing game, they are not very good at making the kill, succeeding perhaps half the time. It is dangerous work at which humans with their weapons excel.
Imagine the scene: Human hunters locate wolves on the hunt by watching ravens who are known to follow them. Human hunters move in for the kill and take as many animals as they can. If smart, they might share immediately with the wolves. If not, the wolves might consume what the humans do not carry off or follow them back to their encampment to take what they can.
The rest is a tale of accommodation through socialization—the ability to bond with another being—and all that entails.
This article originally appeared in Psychology Today's Dog's Best Friend, used with permission.
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