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.
We may think our dog wIll take a treat from any hand that offers it, but a new study by a team of Japanese researchers suggests that may not be the case. Primates engage in something called “social eavesdropping”— essentially, making judgments about others based on interactions that don’t directly affect their own interests. This study tested dogs’ ability to do the same by setting up situations in which the dogs’ owners asked for help in opening a box and were assisted (helper scenario), rejected (non-helper scenario), or ignored (control scenario) as the dogs looked on. After these interchanges, when the dogs were offered treats, they took them randomly from Helper and Control “strangers” but were biased against non-helpers. According to Kazuo Fujita, professor of comparative cognition at Kyoto university and one of the study’s authors, the ability to socially and emotionally evaluate others “is one of the key factors in building a highly collaborative society.” So, another step in the process of understanding how Canis lupus became familiaris: like humans, dogs are able to pick up clues about who to trust and who to avoid.
Good Dog: Behavior & Training
Technology facilitates communication
What if dogs could talk? Specifically, what if service dogs and bomb-sniffing dogs could talk? Associate Professor Melody Moore Jackson at Georgia Tech, and a team that includes Professor Thad Starner, Research Scientist Clint Zeagler, and Jackson’s Border Collie Sky, are developing technology that allows dogs to say anything we give them the capability of saying. They’ve called their project FIDO, which is short for “Facilitating Interactions for Dogs with Occupations.”
They developed a vest with sensors on it that dogs can activate to communicate. The vest can play a message or send a text to a smart phone. From a training perspective, it’s a basic system—dogs are trained to hit specific sensors in response to certain cues. So, if asked which toy a person is holding, the dog can hit a sensor that plays a message that says, “That is the Frisbee®” or “That is the ball.” That is a cool trick, but the real genius of this vest is the variety of messages dogs can send.
For example, a service dog for a hearing-impaired person might hit a sensor in response to an alarm that sends a text saying, “I heard the alarm,” and a different sensor in response to the doorbell so that the message reads, “I heard the doorbell.” Many hearing impaired dogs lead their person to the source of a sound, such as a crying baby. This vest adds to the benefits of a service dog because it would also allow a person to be notified of a sound that is not reachable, such as a tornado siren. Just like distinguishing between the ball and the Frisbee®, telling these sounds apart is a type of discrimination task, and is the basis for many of the ways that this vest can be used.
For example, detection dogs are usually trained to bark if they find what they are looking for, perhaps a drug or an explosive. Although dogs are often trained to search for multiple types of drugs or explosives, they are limited in their ability to communicate the details of their finds to their handlers. It can make a big difference to everyone’s safety if the dog can let a handler know that the bomb is a stable type or an unstable one that needs careful handling. This vest can allow a dog to share more specific information.
This group developed a vest that allows a dog who has found anyone trapped after a natural disaster to activate a sensor with a message for that person to hear. The message lets the trapped individual know that help is on the way. Work is underway to develop a vest that allows a dog to activate a sensor that sends GPS coordinates to a handler. This allows the handler to join the dog, who does not have to leave the person who has been found. That could be lifesaving for a child who is hiding or for a person who is unable to move for whatever reason.
Similar technology could benefit people with any number of health problems. Imagine that a person with epilepsy has a seizure and the service dog has been trained to activate a sensor in response to that situation. The activation of the sensor would result in a call to 911 and also send a message to a family member. The message would include GPS coordinates and say, “My person had a seizure and 911 has been contacted.”
The possibilities of this technology are limitless. A dog could be trained to hit a sensor in response to someone saying, “Get help.” When that sensor is hit, a recording plays so anyone nearby hears, “My owner needs your attention. Please follow me.” This technology is very exciting because it allows dogs to communicate specific helpful information to people. The beauty of the design is that it is relatively easy to teach dogs with a solid base of training to activate sensors in response to specific cues. These vests represent a wonderful blending of solid dog training with new technology to increase the ability of dogs and people to accomplish a variety of tasks together.
Culture: Science & History
What can archeology tells us about the “connection” origins.
Studies of prehistoric dog burials have been making splashy headlines lately. Although the popular press would have us believe that these finds are proof of the affectionate relationship our ancestors had with dogs, the unifying theory that gives meaning to burial patterns remains elusive because ancient people left no written record.
What little we know about dogs’ social roles in antiquity is a patchy mosaic of information derived from physical analysis of bones excavated from gravesites. The accuracy of this mosaic has been further complicated by archaeologists’ long-standing difficulty with reliably distinguishing between wolves and dogs, not only because the two animals look similar, but also because changes in morphology during the early stages of domestication were subtle.
However, in 1986, zooarchaeologist Darcy Morey, now adjunct professor in anthropological sciences at Virginia’s Radford University, developed a statistical equation to more accurately identify dissimilarities between skulls. A decade later, geneticists were able to extricate even more conclusive information from DNA. Then, in a landmark paper published in 1999 in the Journal of Heredity, geneticists Carles Vilà, Jesus Maldonado and Robert Wayne suggested that the first domestication event occurred more than 100,000 years earlier than dog burial remains suggested. This marked the beginning of a decades-long trend that all but excluded archaeology and other academic disciplines from the equation.
Morey—and later, Greger Larson, evolutionary biologist in Durham University’s Department of Archaeology in the UK—challenged the exclusive use of DNA analysis to identify the time and place of the first domestication event. They advocated a return to a cross-discipline approach that included traditional archaeology, DNA analysis, isotope geochemistry and radiocarbon dating in the context of environmental sciences such as paleoclimatology and biogeography.
Robert Losey, associate professor of anthropology at the University of Alberta, is among the scholars who agree with this approach. “When the genetic information can be integrated with information on dogs’ diets, diseases, activity patterns and archaeological context, we get a much more complex and informative picture of people’s emotional and day-to-day lives with their animals than we can through genetics alone.”
Siberia’s Lake Baikal, the largest and oldest freshwater lake in the world, is known for its well-preserved Middle Holocene (3,000- to 9,000-year-old) hunter-gatherer cemeteries, which attract scientists studying how social and environmental pressures influence long-term cultural change. Leading a team of researchers from various disciplines, Losey analyzed numerous Lake Baikal sites containing human, dog and wolf remains dating back 5,000 to 8,000 years; the team’s findings were published in 2011 in the Journal of Anthropological Archaeology.
As he explained, “What I tried to do in my study was to approach these dog skeletons just like we would a human skeleton. We applied a suite of analyses in order to tease out the interesting and relevant details of their lives. The best way to fully understand the domestication of dogs is to use as many forms of evidence as possible, and to employ a wide range of specialists.” Their interpretive model was partly based on ethnographic records of indigenous groups from across the northern hemisphere. For example, many northern people, who have an animistic understanding of their world, strongly believe that animals, plants and inanimate objects possess souls.
Using stable isotope analysis, researchers determined that dog and human diets were the same. In comparison, a wolf found buried in the same area had foraged on large game, a diet different than that of local people. Some dogs were buried with artifacts the dog would have used or been familiar with during its life: a decorative collar-like pendant made with red-deer teeth, a round ball-like stone, spoons, antlers and other implements.
Bone-wear suggested that the dogs had worked alongside people, likely as transport animals hauling heavy loads. Some had recovered from injuries that would have required special care. People and dogs were buried near one another in the same cemetery, and in some cases, were buried together (in one instance, a man was buried with two dogs, one on either side). Analysis of the dogs’ skeletons revealed a resemblance to modern-day Siberian Huskies, although they would have been larger. Genetic work on the specimens confirmed an ancestral link to our modern dogs.
According to Losey, “I think what we are really looking at is a set of relationships between people and dogs, and to study relationships, we need to try to understand the life histories of animals, not just their evolutionary history.”
Putting all of the small parts together, the researchers painted a big picture. They suggested that ancient indigenous people considered some dogs to be very special. Unlike the majority of simpler animals, whose spirits collectively recycled after death, these dogs were thought to be like humans, with powerful and unique souls that required mortuary rites similar to those of deceased people.
This special treatment was necessary for both dogs and humans so that their souls could return in new individuals. Losey added, “I think the act of treating a dog as a human upon its death indicates that people knew it had a soul, and that the mortuary rites it received were meant to ensure that this soul was properly cared for. These practices also clearly indicate that people had close emotional bonds with some of their dogs, and perhaps mourned their loss like they did [the loss of] their own family members.”
Waves of Proto-domestication
Although romanticized images of digs in the shadows of ancient civilizations continue to feed the popular notion of archaeology, a more accurate but less dramatic scene would have scientists in white lab coats conducting microscopic analyses of polymorphic nucleotides extracted from bone remnants stored for many decades on museum shelves. Indeed, bones unearthed long ago have proven to be quite revelatory. The most unexpected discoveries regarding the human/dog relationship are based on analyses of materials extracted from canid bones excavated, catalogued and archived in 1873 and 1884, respectively.
The oldest skull, which dates to 31,700 years ago, was found at Belgium’s Goyet Cave. Another from a site in Predmosti in the Czech Republic proved to be about 27,000 years old. One skull from the Predmosti site had a mammoth bone fragment in its mouth. Does it indicate that a special connection had developed between people and dogs as far back as 30,000 years ago? Archaeologist Mietje Germonpré of the Royal Belgium Institute of Natural Sciences—lead author of the two papers describing the 2008 and 2012 research results—said, “I believe that the dog skull with the bone between its teeth suggests some sort of ritual treatment. The position of the bone fragment in the mouth suggests that it was inserted between the incisors of the dog post-mortem.” The ethnographic record indicates that placing body parts between the teeth of dead carnivores was a common practice in many cultures. Exactly why remains open to speculation.
Paleoanthropologist Pat Shipman, who has written extensively on the evolutionary impact of the human/animal connection, suggested that the mammoth bone points to a cross-species alliance that may have developed even earlier—one that might account for the success of our early ancestors. She hypothesized that proto-dogs, like those found at the Predmosti site and at Goyet, cooperated with humans in a symbiotic hunting partnership that could account for the significant and abrupt increase in the number of animals found at mammoth kill-sites dating as far back as perhaps 45,000 years. The initial domestication of dogs may have been accidental, but once humans realized the value of these living “tools,” they began to refine them for increasingly specialized purposes.
In a separate study, a group of researchers led by Ole Thalmann examined ancient DNA of Eurasian dogs (the Predmosti dogs had not been genotyped) along with others, and came up with some surprising results. Separated by only a few thousand miles and a few thousand years, the ancient dogs were not related to each other, nor were they related to modern dogs. In addition, none of the lines survived, which suggests that domestication experienced many starts and stops in different regions with different wolf populations. Scientists speculated that the last ice age, which began about 26,000 years ago, might have contributed to this stutter-step process. They also found that living dogs are more closely related to ancient, extinct wolves than they are to modern wolves.
If domestic dogs somehow catastrophically died out, would we have the natural resources needed to recreate them? In Shipman’s opinion, “The answer is both no and yes. If dogs disappeared, they probably couldn’t re-evolve from the wolves we have now. But those extinct wolves evolved into contemporary wolves, and canids in general have a huge amount of variability in their genomes, which is why we have so many different types of dogs today. If by ‘dogs,’ you mean a highly variable canid that can live with and cooperate with humans, then I think the answer is yes. Would it be the same dog as today? We can’t be sure.”
Laid to Rest with Care
In the past two decades, archaeologists have unearthed the remains of about 1,400 dogs buried 2,500 years ago on prime ocean-view real estate in ancient Ashkelon, today a thriving city located on the Mediterranean Sea, 30 minutes from Tel Aviv. The dog burials spanned a period of eight decades. Carefully positioned alone in shallow pits, the dogs’ bodies were placed on their sides, legs flexed, tails gently tucked around their hind legs. Ranging in age from newborn through elderly, they appear to have died of natural causes.
Ashkelon is only one of thousands of ancient dog-burial sites scattered across the globe, and its large number of burials raises the question, “How many dogs were buried in antiquity?” The answer is, “We’ll never know.” Throughout prehistory, people mostly disposed of bodies, human and non-human, in untraceable ways; they sent them floating down rivers or buried them in shallow earthen graves—reverent practices that lost them to the ages.
In addition, dog burials were so common that they are field sites’ most overlooked artifacts. In her 2009 manual, A Practical Guide to In Situ Dog Remains for the Field Archaeologist, Susan Crockford, adjunct professor at the University of Victoria in Canada who has worked with dog remains for more than 20 years, maintains that far more dog burials are encountered than are ever mentioned in archaeological site reports. Workers aren’t properly trained to recognize dog remains, nor do most understand the history of dogs and their significant contribution to the human story. Consequently, much of what we could have learned about the human/dog connection has been lost forever.
Furthermore, scientists can’t develop statistical estimations because it’s unclear whether or not dog burials are representative of the total dog population. However, by calculating the timing of genetic bottlenecks, Thalmann and his colleagues suggested that ancient dog populations paralleled the trajectory of human population growth. Dog numbers increased steadily until about 5,000 years ago, then abruptly declined, followed by a sharp increase 2,500 years later. Even if their calculations are proven accurate, whether (and why) certain dogs were selected for burial while others were not remains unclear.
The first comprehensive review of dog burial studies, “Burying key evidence: the social bond between dogs and people,” by Darcy Morey, published in the Journal of Archaeological Science (2006), put the documented cases and site locations in perspective. Written for a scholarly audience but with enough humanity to appeal to lay readers, the paper brought new attention to a topic of inherently widespread interest. Given that so many burials are untraceable and others are uncertain, why even suggest a total?
Professor Morey said, “Depending on circumstances, for a given site, I think it’s possible to suggest how many were buried, at least in that place.” In a later book, Dogs: Domestication and the Development of a Social Bond, Morey included an appendix that inventoried dog burials, including totals as known from specific places. “But,” he added, “given frequent uncertainties, I think in general that suggesting combined totals is fraught with problems.”
As companions and helpers, dogs hold a special place in our hearts, and increasingly, as our equals in relation to our place in the collective physical world. Mary Elizabeth Thurston, author of The Lost History of the Canine Race, anthropologist and historian for Hartsdale Pet Cemetery in Westchester, N.Y., said, “Fifteen years ago, about 55 percent of the public believed pets deserve mortuary rites in death. Today, the number is much higher.”
Thurston also noted an uptick in the number of people who wanted to be laid to rest with their animal companion, either by arranging for their own cremated remains to be buried with the pet, or for the cremated remains of that animal to be interred with them. “When animals fill an innate need for companionship as either surrogate children or life partners, they become truly indispensible in the eyes of their human caretakers. The desire to be together is understandable. The grief felt at the death of that pet is profound, and people want to accord their animals a measure of respectful remembrance in death, just as [they] would any other family member. However, we can’t assume that ancient people, who left no written records, held our same modern sensibilities.”
Canine remains in ancient human burial pits more often indicate that the dog was part of an offering, sacrifice or spiritual ritual rather than a companion. Thurston suggested that the ancient interment of single animals with grave goods, especially things that the dog used in life, along with evidence that shows the dog died of natural causes, might suggest an affectionate relationship and the belief that the animal had a soul—that, like people, it would need these things on the “other side” for a good life.”
In “Peru’s Mummy Dogs,” writer Roger Atwood noted that in 2006, Sonia Guillén, archaeologist at the Maliqui Center in Ilo, Peru, reported that her team had discovered 40 dogs buried about 1,000 years ago in separate plots alongside the remains of what were probably their owners. The discovery was unusual in that the dogs were interred with items that look like toys and food. As Guillén, who studies Peru’s Chiribaya culture (which pre-dated the Incas), told the press, “We have found that in all the cemeteries, always, in between the human tombs, there are others dedicated to the dogs, full-grown and puppies. They have their own graves, and in some cases they are buried with blankets and food.” Guillén, who suspects that the dogs may be direct ancestors of the companion and working dogs who populate the village today, is collecting DNA for future study.
Most human/dog burials occurred 5,000 to 8,000 years ago in hunter-gatherer societies and disappeared with the beginning of the agrarian era. But their absence doesn’t equate to a lack of an affectionate human/dog connection. At the Lake Baikal site, when pastoralists inhabited the area beginning about 5,000 years ago, they did not bury dogs, at least not in areas where archaeologists might find them. According to Robert Losey, “The difference between the pastoralists and the hunter-gatherers living in this area of Siberia is that the hunter-gatherers buried some of their dogs in cemeteries used otherwise for the human dead. The pastoralists do not appear to have done this.
“Over the past few years, my colleagues and I have interviewed local Buryat people, who are descended from some of these early pastoralists, about their dogs, and they clearly have a deep respect for [them], and do bury some of them. However, they are not considered non-human persons with individual souls, and in the local belief systems, are not spiritually equivalent with humans. So, they cannot be buried in local cemeteries. The best dogs, and the most loved ones, are given burial rites in some cases, but these tend to be elsewhere—on the tops of hills or mountains, for example. Some folks even recounted that they left pieces of meat in the graves with the dogs—food for them in the afterlife.”
As long as dogs have existed, they have been deliberately buried in every region they inhabited. Moreover, dogs have been buried more often than any other animal: singly, with other dogs, near people and with people. This ancient practice was a global phenomenon, one that crossed nearly all cultural boundaries. Precisely why dogs were buried may never be clearly understood, but the universality of the practice suggests it may be embedded in the human psyche and accordingly, is a fundamental part of the human/dog connection.
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