News: Guest Posts
Dogs and wolves share a similar genetic profile. So why are their behaviors so different?
The reasons aren’t clearly understood. In a recent paper in the journal Ethology , evolutionary biologist Kathryn Lord's doctoral research (University of Massachusetts, Amherst) suggests differences in later behaviors might be related to the pups' earliest sensory experiences during the critical period of socialization, the brief period when a puppy's exposure to novel things results in long-term familiarity.
Lord's research demonstrated that dog and wolf pups acquire their senses at the same time:
· Hearing: Onset 19 days, reliable by 28 days
· Seeing: Onset 26 days, reliable by 42 days
· Smelling: Reliable by 14 days (onset likely earlier)
· Dog pups wait until 28 days to explore their environment when all senses are operational.
· Wolf pups begin exploring the world at 14 days, relying solely on scent, when they are still blind and deaf.
Although wolves are tolerant of humans and things they were introduced to during the critical period, they don't generalize that familiarity to other people or novel things when they mature. Dogs on the other hand, can generalize, and if properly socialized are not spooked by novel sounds and sights.
Why do mature dogs and wolves behave so differently? Lord's conclusion is that at the gene level, the difference may be when the gene is switched on, not the gene itself.
What could that mean? Research has shown that the brain is capable or rewiring itself in dramatic ways. Early loss of a sense affects brain development. For instance, even though the developing auditory cortex of a profoundly deaf infant is not exposed to sound stimuli, it doesn't atrophy due to lack of use. Rather it adapts and takes on processing tasks of other senses including sight and touch. Perhaps wolves see the world in smell, and dogs see it a lot more like we do.
Click here to read the paper, A Comparison of the Sensory Development of Wolves (Canis lupus lupus) and Dogs (Canis lupus familiaris), by Kathryn Lord, Ethology, February, 2013.
Good Dog: Studies & Research
Research shows that for dogs, actions count
My suspicions were confirmed on December 26, 2002, while at the Metreon Theater in San Francisco. As the youngest in the family, my job was to wait in line for tickets, and, knowing this, I went prepared with a scientific article titled, “Do dogs respond to play signals given by humans?” The research, lead by Nicola Rooney at the Anthrozoology Institute in Southampton, UK, featured 21 dog/owner pairs playing—or at least, attempting to play. In what could surely have been billed as a comedy, owners patted the floor, barked, bowed, shuffled their feet, slapped their thighs, crawled on all fours—anything to get their dogs to romp with them.
The researchers videotaped the sessions and meticulously catalogued, recorded and identified common actions used by owners to solicit play. They then tested to see which signals actually worked. As expected, bowing in a human version of a dog play-bow, as well as lunging while verbally encouraging the dog, usually elicited play. Other gestures, such as tickling the dog as though she were a human infant, or stamping one’s feet as though dislodging last week’s dried mud from hiking boots, just earned blank looks. And surprisingly, patting the floor and clapping were less than 50 percent successful. What’s more, while barking at, kissing or picking up the little pooches probably brought on laughs from the researchers, most dogs failed to find these actions amusing.
As interesting as these findings were, the real message—one that stayed with me—was what came next. Upon analyzing the data, the researchers found that although some actions tended to instigate play while others resulted in silent stares, the frequency with which the owners used the signals was unrelated to their success. In other words, owners tended to use unsuccessful gestures even after they were demonstrated not to work. And there I had it, scientific proof: Dogs are smarter than humans. Well, at least in some ways. You see, dogs are champions at trial-and-error learning. They have all day to try things out and see what works.
For instance, want to play fetch when your people aren’t interested? Grab a tennis ball and drop it at your human’s feet, and then bark until he finally picks it up and tosses it. Getting the silent treatment? Bark longer and louder—you’ll eventually get a response. Or, choose the right time, like when your human’s on the phone; that’s when they’ll do anything to get you to shut up.
While dogs are masters of this style of learning, we humans are hindered by our much-vaunted cognitive abilities. Armed with the wonderful capacity to observe and imitate, we copy the behaviors we see, whether they work or not. Clouded by our preconceptions of the techniques we’re supposed to use, we forget to stop and evaluate whether our actions or methods actually work.
This might seem like fun and games when it’s just us dancing around trying to get our dogs to play. At worst, when our pooch refuses to romp, we attribute it to her not being in the mood. But when it comes to something more important, like coming when called or sitting on command, a dog’s failure to perform can result in her being labeled “stubborn” or “stupid.” Because what else could it be?
Well, according to a series of research studies by Daniel Mills (veterinarian and researcher in Behavioural Studies and Animal Welfare at the UK’s University of Lincoln), as with play signals, much poor performance could be attributed to dogs’ inability to decipher our signals. It turns out that even if our dog responds to our commands some of the time, she may not know what they mean as well as we think she does.
According to Mills, a number of factors determine how well our dogs perceive the message we intend to give. One is whether the signal is verbal or visual. While we humans are used to communicating by talking, Mills’ research indicates that this may not be the best mode of communication with dogs. In an experiment to test which signal type takes precedence, Mills and his colleagues trained dogs to respond to a verbal right and left cue as well as a visual pointing cue for the same behaviors. To guard against bias that could be created by the order of teaching, half of the dogs were initially trained using verbal cues and the other half, using visual cues
Then they tested the dogs by placing a treat-holding container on either side of the subject—one box on the right and one on the left. When they gave the “left” cue, the dog got the food reward if she ran to the box on the left. If she ran to the wrong box, she got no reward. Once dogs consistently responded correctly to verbal and visual cues alone, the cues were given together, with a twist. The researchers gave a verbal signal for one direction and a visual signal for the other to see which one the dogs would follow. For anyone whose dog competes seriously in agility, the results were a no-brainer: The dogs consistently followed the visual pointing cue and ignored the verbal cue. This dynamic plays out on every agility course—a dog will usually go where her handler’s body is pointing rather than where the handler might be verbally trying to send her.
This bias toward the visual as opposed to the verbal can pose problems for dogs even in everyday life, says Mills, “This simple example emphasizes that when training dogs, we have to realize that dogs may be reading signals we’re not aware of.” So when your voice tells the dog to do one thing but your body tells her to another, she’s not being stubborn—she may just be reading a different message than the one you think you’re sending.
Even when we’re purposefully sending visual commands to our dogs, such as in the obedience trial ring or field trials or other long-distance work, there’s more to the signal than we might think. Says Mills, “In a similar study, we looked at the dog’s response to different visual right-and-left cues. We compared eye movement and head movement to the right or left with pointing right or left, but keeping the eyes and head looking forward.” Using six dogs, they found that dogs found the hidden food source faster when the two signals were presented together which, Mills says, suggests that “Dogs are taking in the whole picture of what’s going on.” That is, they don’t look at our hands or our head, they look at our entire body. As a result, if all signals are not consistent, dog can become confused.
Do these studies mean we should scrap verbal commands altogether and focus on the visual signals? Obviously, dogs can learn verbal commands, because we use them all the time and some dogs respond correctly on a regular basis. But perhaps even those who respond don’t know the cues as well as we think. Mills and his colleagues performed a series of studies to test this, too. First, they tested slight variations in the commands to see if dogs recognized them as the same words. They taught dogs to stand and stay, and then, from five feet away, the trainer gave either a “come” command or a “sit” command.
Once the dogs were reliable about responding correctly, the researchers changed the command words slightly. In place of “sit,” they used “chit,” “sat” and “sik,” and in place of “come,” they used “tum,” “keem” and “kufe.” The results? In general, dogs did not respond as well to the similar-sounding words; or, taken from another viewpoint, they were able to recognize that the similar-sounding words were not the same as the commands they had learned. This sounds like no big deal, but, says Mills, “From a practical point of view, due to slight differences in how handlers pronounce words, obedient response to one handler’s commands won’t necessarily transfer to another unless the phonemic characteristics are mimicked.”
You might think you could get around this by tape-recording the command and just playing it back, but Mills found that dogs don’t respond to tape-recordings as though they were a real-time human voice. In yet another experiment, a “come” or “sit” command was given in one of four conditions: from a person sitting in a chair; from the same person wearing sunglasses to prevent visual cues; and both conditions, but the command issuing from a tape recorder behind the person. Says Mills, “Dogs made many more errors when the tape recorder was used.”
Such errors could be attributed to the dogs distinguishing a difference between the tape-recorded and live voice command, but another hypothesis is that dogs also rely on lip movement or some other indication that the human is speaking to them. In fact, in a fifth variation, the handler uttered the “come” or “sit” cue while looking away from the dogs, and they again made many errors, indicating that orientation of the handler is important.
By now, it should be clear: Be aware of visual signals, as they may override the verbal commands. Make sure all of your signals mean the same thing, or your message may look more like a dubbed version of Godzilla than a clear-cut cue. When you do use verbal cues, make sure everyone says them exactly the same way, or train your dog that slight variations mean the same thing. And if you plan on your dog responding correctly to your verbal commands when you’re out of sight or facing away, you’ll have to specifically train him to do so.
And that’s not the end of it. Turns out that the emotional content of your message is important too. Mills’ group trained dogs to reliably come or sit when a handler was standing five feet away behind a screen. Then they tested to see how dogs responded to different emotional contents. The commands were uttered in a neutral tone; a happy tone, with the inflection ascending; an angry version, with the tone descending; and a gloomy version, in which the handler sighed first. Dogs responded more predictably when the tone was positive, but when the command was said in an angry or gloomy manner, there was more variation in their responses.
So what’s the take-home message? The one your pooch is dying for you to learn? Here it is: Perhaps when your dog gives you a blank stare after you utter a command you think he knows, she has a good reason. Because when communicating with our pets, it’s not just what we say, it’s how we say it and whether our visual and verbal cues are sending the same message. Once we become more aware of the signals we send to our dogs and how they perceive them, we can cut down the number of everyday frustrations and open clearer lines of communication with our four-legged friends.
Dog's Life: Lifestyle
Could this study be improved?
In the recent study “Can domestic dogs (Canis familiaris) use referential emotional expressions to locate hidden food?”, researchers investigated whether dogs have the ability to locate hidden food based on the emotions shown by people’s facial expressions. It’s a fascinating question, and I was eager to learn what the experiment revealed.
Unfortunately, I had concerns related to the methods, and the result was that I found that the experiment lacked the strength it could otherwise have had. When I read scientific papers, I pay careful attention to the methods because unless I fully grasp the details of the experimental design, it is impossible to draw conclusions about the meaning of the study. Often, flaws in the methodology result in studies whose conclusions should not be accepted without further evidence from better experiments.
In the study I just read, people picked up two boxes, one at a time, and made facial expressions of happiness or disgust or they kept their expression neutral. Then, the dog was given a choice about which box to go to. (The dogs had been trained to understand that these boxes could contain food.) The idea was to see if the dogs would choose the box that was associated with happiness rather than the box associated with disgust or with a neutral expression. Overall, there was an effect of the human expression on the choices made, though many individual dogs made choices throughout the trials that were no better than chance.
The location of the testing was not always the same. Some of the dogs were tested indoors, and some were tested outdoors. Four breeds of dogs (Labs, Goldens, Border Collies, and German Shepherds) were pet dogs who lived with families in homes, and were tested indoors, but the Huskies lived in a facility for racing dogs and were tested outdoors. The investigators did in fact find a difference between dogs tested in these two conditions, but there is no way to tell if this is because of the breed, because they were tested outdoors, or because of their different social situation, which the experimenters acknowledge. With more than one variable present, determining which variable matters is a challenge.
Since the whole point of the experiment is to test the effect of human facial expressions, then the facial expression should be the only variable in the experiment. Unfortunately, in this study, other variables besides the ones already mentioned were not held constant. The “happy” box contained sausage, the “neutral” box contained wood shavings, and the “disgust” box had garlic in it. The neutral expression had no accompanying vocalization, but both the happy and the disgusted expression did. If the dogs did respond differently to any of these conditions, it’s hard to know whether or not the contents of the box, the presence or absence of a vocalization, or the people’s expressions (or some combination) was the cause.
In a better-designed experiment, all the boxes would contain exactly the same item, and the other differences not being tested would be eliminated as well. The researchers did a series of tests to determine if the dogs were choosing boxes based on smell alone, but only in the outdoor condition with the Huskies. (They found that these dogs were not using smell.)
To be fair, the researchers spend quite a bit of space in their discussion explaining how this experiment could have been done better in a cleaner way, scientifically speaking. I agree with their analysis that improvements could be made to the design that would add strength to their conclusions. I would have preferred for them to conduct their experiments with the improved designs before publishing, though I understand that it is immensely challenging to explore cleanly the role of human emotion in influencing dog behavior.
There are so many variables with pet dogs because of the different amounts and types of experience they have in their lives, and not only are they impossible to control for. Even if you could control many factors by raising dogs in labs and controlling their environment, then you introduce the problem of dogs who are not in the “pet dog” environment. I’m not saying that an experiment into these issues can ever be perfect, but I do think that this study could be improved upon.
Dog's Life: Lifestyle
Dog Cognition Lab is looking for play videos
A couple years ago, I brought my two Shelties to the Harvard Canine Cognition Lab to participate in a study on dogs’ understanding of human gestures. Boston isn’t exactly close, but I was happy to drive the three hours to check out the research being done on the canine brain.
As pets become a bigger part of our lives, universities are getting more funding to understand what going on in our dogs’ heads. Schools with canine cognition programs include Harvard, Barnard, Duke, University of Florida, Eckerd, and University of Kentucky.
Canine cognition labs are always looking for dogs to participate in their research, but for those not willing to travel, now you can participate in a study without leaving the comfort of home.
The Dog Cognition Lab at Barnard College in New York is currently looking at play between canines and humans. To participate you need to complete a short survey and upload a 30-60 second video of you and your dog playing. They’re interested in seeing how people typically play with their pets and are not looking for any specific style.
Past research at Barnard has included studying olfactory discrimination, anthropomorphisms (such as the concept of “fairness” and the “guilty look”), use of attention and play signals in social play, and communication between dogs.
I think the human-canine play study will be particularly interesting since the videos will allow people and dogs around the world to participate. And it’s a cool way to bring animal lovers together in the name of scientific research… not to mention while having fun playing with our dogs!
Good Dog: Studies & Research
“This is not your food! Don’t even think about eating it. This … is … not … your … food.” What do our words mean to dogs? Not that I’m about to stop speaking to dogs anytime soon, but I do wonder what my daily utterances signify to Millie, Piper, Upton and Finnegan, the dogs I converse with on a regular basis. Do I sound like a cross between Charlie Brown’s teacher and Gary Larson’s “What Dogs Hear” cartoon? Are we on the same page, or even in the same book?
I set out on a quest to explore dogs and their understanding of human language. What do we think dogs understand? A lot, according to a study by Péter Pongrácz and his colleagues at the Family Dog Project in Budapest. Thirty-seven owners provided a list of 430 different utterances that they thought their dogs knew, with each owner providing an average of 30 phrases.
Enter Rico, Chaser, Sofia, Bailey, Paddy and Betsy, companion dogs celebrated for their panache for human language. The news media hails them as “super smart,” and after meeting Chaser, astrophysicist Neil deGrasse Tyson exclaimed, “Who would have thought that animals are capable of this much display of intellect?”
So what are these dogs doing with words?
Seven years later, Chaser, a Border Collie in South Carolina, took the gold medal when Alliston Reid and John Pilley of Wofford College reported that Chaser knew the distinct names of 1,022 objects — more than 800 cloth animals, 116 balls, 26 Frisbees and 100 plastic items. Chaser knows that “Uncle Fuzz” is different from “Wise Owl,” who is certainly different from “Merlin.” This is not merely a story about Border Collies, however. Researchers recently related that Bailey, a 12-year-old Yorkshire Terrier, knows the names of about 120 toys.
Chaser and Rico also win praise for their ability to learn and retain the names of new objects. When presented with a group of toys, all of which were familiar except one, the dogs could retrieve the unknown toy when asked to fetch using an unfamiliar word. In essence, the dogs were pairing a novel object with an unfamiliar name after a single association and then remembering the name of that new object in subsequent trials. In children, this is called “fast mapping,” and it was thought to be uniquely human. Pilley notes, “This research shows that this understanding occurs on a single trial. However, Chaser needed addition rehearsal in order to transfer this understanding or learning into long-term memory.”
“That’s just training,” you might say, but this suggests that some dogs show a cognitively advanced skill where actions are understood as independent from objects. Reid and Pilley found that Chaser does not interpret “fetch sock” as one single word, like “fetchsock.” Instead, she can perform a number of different actions flexibly toward a number of different objects. Daniela Ramos, a veterinary behaviorist in São Paulo, discovered that a mutt named Sofia could also differentiate object names from action commands, suggesting these dogs attend to the individual meaning of each word.
This all seems quite extraordinary, but nothing comes free of controversy. Do dogs like Chaser and Sofia use and understand language the same way humans do, or are they merely welltrained? For example, some researchers are not certain that dogs actually “fast map”; dogs might be doing something that simply looks like “fast mapping” from the outside. Regardless, it does seem as though these dogs have a conception of objects and actions. Patricia McConnell, PhD, Certified Applied Animal Behaviorist and beloved Bark columnist, agrees. “Understanding requires that we share the same reference — that we have the same construct of an object or an action. For some dogs, it seems like they do.” Pilley concurs. “When an object, such as a toy, is held before Chaser and a verbal label is given to that object, Chaser understands that the verbal label refers to that object.”
In her book Inside of a Dog, Alexandra Horowitz reminds us that even if these are the only dogs in the world capable of using words this way, it allows us to see that a “dog’s cognitive equipment is good enough to understand language in the right context.” This body of research indicates what is possible, not necessarily what most dogs do every day.
Who Are You Living With?
Like Rocky Balboa preparing for his climactic showdown, these dogs are highly motivated. Fischer notes, “Rico was eager and hard working. You’d have to tell him, ‘That’s enough. Get something to drink. Take a rest.’” Chaser is similar, says Pilley. “She has two states—highly, highly active and recuperating and resting.”
Denise Fenzi, a professional dog trainer from Woodside, Calif., who specializes in a variety of dog sports, reminds us that this type of motivation is not necessarily the norm. “Not all dogs share this attention to words. Even in my dogs [all of whom are the same breed], there is a huge difference in ability to verbally process. I didn’t train them differently. It’s just easier for one to quickly get words.”
What dogs are able to do with language could also be explained by their tutelage. If dogs don’t learn to attach a variety of different actions to a variety of objects, it might be harder for them in the long run to be flexible with human language. Susanne Grassmann, a developmental psychologist and psycholinguist at the University of Groningen in the Netherlands explains, “Chaser was trained to do different things with different objects, and she differentiates between what is the object label and what is the action command, meaning what to do with that object.”
Ramos notes that Sofia’s relationship with certain objects was a bit different. “Throughout the training, we always paired ‘stick’ with ‘point.’ As a result, it was difficult for her to perform any other action toward the stick beside ‘point.’ If we had trained her ‘stick: sit,’ ‘stick: point’ and ‘stick: fetch,’ she would have learned that multiple actions can be directed toward the stick, and her response would probably be different. For example, when presented with a novel object, such as a toy bear, she could direct a number of different actions toward the bear, but there was a reluctance to change her action towards the stick, which could have to do with the rigidity of training.”
And even if you do explicitly teach that different words have different meanings, it can be challenging. Ramos found that learning the names of objects is not always easy for dogs. “It was hard for Sofia to learn to discriminate the names of her first two objects, but after the initial discrimination, it was like she learned to learn. It became easier,” recalls Ramos.
“Because this type of learning can be challenging, service dogs [who have little margin for error] are taught a limited, but instrumental, set of words,” explains Kate Schroer-Shepord, a qualified guide dog instructor at Guiding Eyes for the Blind in Yorktown Heights, N.Y.
Pilley found that dogs’ success at object learning depended upon the training method used. “When we put two objects on the floor and asked dogs to retrieve each object by name, they couldn’t do it; simultaneous discrimination wasn’t working. Instead, Chaser was able to learn the names of objects through successive discrimination. She would play with one object in each training session, and through play, the object assumed value. We’d name the object, hide it and ask her to find it. Discrimination testing between the names of different objects occurred later.”
Words or Melody?
Dogs derive an enormous amount of information from contextual cues, particularly our body movements as well as tone and “prosody” — the rhythm, stress and intonation of our speech. “When people talk to dogs, dogs pay attention to the melody and the mood to predict what is happening or what will happen next,” explains Fischer.
Fenzi says that dogs can just as easily respond to gibberish as to real English words; “I could go through every level of AKC obedience from the bottom to the top saying, ‘Kaboola,’ and the dog could succeed.” In many cases, dogs may be understanding tone rather than individual words.
“One of the most notable differences between novices and professional trainers is the ability to modulate the prosodic features of their speech,” notes McConnell. “The pros learn to keep problematic emotions out of their verbal cues, like nervousness in a competition, and to use prosody to their advantage when it’s advantageous, for example, to calm a dog down or to motivate him to speed up.”
In another study, Ramos explored whether, when taken out of context, dogs knew the words relating to toys they were thought to know. Most did not, much to the surprise of the owners. When the verbal skills of Fellow, a performing German Shepherd from the 1920s, were tested outside their customary contexts, Fellow knew only some of the words and actions that his owners thought he understood.
While many owners deem their dogs to be word-savvy, their reports tell a different story. The Pongrácz survey found that many words and phrases were executed only in contextually adequate situations (for example, saying “bedtime” when it’s dark and you’re in your pajamas rather than at noon when you’re in your work clothes). As with Fellow, this suggests dogs might not be attending to only words themselves.
Put Words to the Test
McConnell initially thought Willie knew the name of her partner, Jim. “To teach Willie, I would say, ‘Where’s Jim?’ and Jim would call Willie over. When Willie consistently went to Jim, I’d say it as Jim was driving up, and Willie would run to the window. One day, Jim was sitting on the couch, and I said, ‘Where’s Jim?’ and Willie ran to the window, all excited. This difference in definitions is more common than people realize — dogs don’t have the exact same concept of words that we do.”
While there is no question dogs can understand verbs, their definitions might differ from ours. McConnell shares a classic example that she learned from Ian Dunbar, founder of the Association of Pet Dog Trainers. “What do dogs think ‘sit’ means? We think ‘sit’ means this posture we call ‘sitting,’ but if you ask a dog who is sitting to ‘sit,’ he will very often lie down. To him, ‘sit’ might mean get lower, go down toward the ground.”
Many people tend to overestimate their dogs’ facility with words and assume that dogs and humans have a shared understanding. Because a dog responds in one context and not in another doesn’t mean he is being disobedient. As Tom Brownlee, master trainer with the American Society of Canine Trainers and instructor in Carroll College’s anthrozoology program, candidly advises owners, “If a dog’s not getting ‘it’ — whatever ‘it’ may be — then you are doing something wrong. It’s our job to help them understand.”
When you talk to your dog, consider that the words you speak might not carry the same meaning for both of you. Instead, other aspects of communication might be more relevant. Maybe the real lesson is that context, prosody and tone — rather than dictionary definitions of words — are vitally important for human communication, too.
This piece is dedicated to Professor César Ades (1943–2012) and Dr. Penny Bernstein (1947– 2012). While their exceptional contributions to the fields of animal behavior and psychology endure, their presences are greatly missed.
News: Guest Posts
Study finds Hormone-disrupting Chemicals Leach from Some Plastic Toys
The toy aisle is meant to be all about fun, but recalls, toxic imports and a dearth of regulations have left dog owners facing tough choices. Many toys are made of plastic and may contain chemicals that interfere with hormones.
A new study by researchers at the Institute of Environmental and Human Health at Texas Tech University shows that BPA and phthalates, chemicals that disrupt hormones, “readily leach” from plastic or vinyl bumper toys used to train retrievers.
Philip Smith, a toxicologist and co-author of the as-yet unpublished study, uses plastic bumpers to train his Labrador Retrievers, Bindi, age 11, and Huck, age 5. He wondered if the bumpers might expose them to hazardous chemicals.
In fact, the compounds are hard to avoid. BPA, the building block of polycarbonate plastic, is found in most food and drink cans; phthalates are common in food packaging, personal care items and vinyl plastics.
“BPA and phthalates come from many, many sources” besides pet toys, Smith says. So a dog’s “cumulative exposure may be significant.”
The study, conducted by graduate student, Kim Wooten, is one of the first to examine these chemicals in pet toys. In children’s toys, some phthalates have been banned in the U.S. and the European Union. In July 2012, the U.S. Food and Drug Administration banned BPA in baby bottles and children’s drinking cups.
Although their health effects in dogs are unknown, the hormones they interfere with regulate many biological functions.
Studies done mostly with rodents have linked BPA and phthalates to impaired development of reproductive organs, decreased fertility, diabetes and obesity, cancers, and behavioral and attention problems.
No, dogs are not mice. There are “species sensitivity differences” in regard to toxics, Smith says. For example, dogs are at greater risk than humans from eating chocolate. But while their sensitivity to synthetic chemicals may also differ, “we are unaware of specific reasons why they might respond in a significantly different manner.”
Available data suggests that the most vulnerable pets may be pregnant females “and perhaps young animals like puppies.”
According to a 2012 pet health report by Banfield Pet Hospital, some cancers and other diseases in dogs are increasing. “The rate of overweight and obese pets has reached epidemic levels in the U.S., affecting approximately one in five dogs and cats.”
The causes are unknown, but Smith says it’s possible that endocrine-disrupting chemicals, including phthalates and BPA, play a role.
Certain aspects of canine cancer suggest that dogs are sensitive to them, he says. For instance, exposure to estrogens raises the risk for mammary cancers. For metabolic disorders such as obesity and diabetes, researchers are finding that some hormone-disrupting chemicals appear to “affect metabolic endpoints, in addition to reproduction and behavior.”
For the toy study, the researchers tested orange and white bumpers from two unidentified makers, using artificial saliva to simulate a dog chewing a bumper. The amount of toxics released in a dog’s mouth couldn’t be determined due to the use of simulated saliva,
But what is a high exposure in dogs?
“We are not aware of any exposure guidelines pertaining to these particular chemicals and dogs,” Smith says.
They suspect the levels released from the bumpers would be very high, though, compared with children’s toys.
The study also examined BPA and phthalates from ordinary plastic pet toys sold in stores. The bumpers leached more, but the results suggest that the other toys might have released other hormonally-active chemicals.
Smith highlights the uncertainty that shoppers face, saying the bumpers might have been made from different materials, or perhaps the packaging limited the release of some chemicals before the experiment.
Or, the less affected toys may have involved “materials that are also used in the manufacture of children’s toys.”
“We’re not really sure, but intend to pursue the question further.”
Good thing for pet owners.
“Given the extent of plastics in the human-canine environment,” Smith says, avoiding the chemicals entirely may not be possible.
But not all plastics are the same. When it comes to leaching of chemicals “each type is very different.”
“That is why studies on individual products are important.” Pet owners need the information “to make thoughtful decisions.”
Some pet toy makers say they use BPA-free plastics.
But owners may wonder why it’s even a question. Why should they have to worry about chemicals in toys or migrating from cans, even into “organic” food, to add to their dog’s exposure?
At least—at last—it is being studied.
Smith’s team plans to continue studying the exposure of pets to chemicals. “We think there is a great deal to be learned about potential pet and human health impacts from chemicals in the environment,” he says.
And as they learn, Smith says they hope to yield the data needed “to inform decisions about how we manufacture pet products, which ones we buy, and what we allow our pets to chew.”
Good Dog: Studies & Research
The Beauty of Diversity
For those of us who love dogs, using DNA tests to deconstruct our mongrel pooch’s mysterious heritage is appealing because we want to be able to answer the question, “What kind of dog is that?” Companies say that DNA-based diagnostic tests, which sell for about $60, can answer the question by comparing your dog’s DNA to over 100 of the most popular breeds. But are the tests accurate? I decided to find out.
Chance, a 10-year-old mixed-breed dog who has lived with me for six years, was my guinea pig. I tested his DNA using three different tests. In 2008, when I wrote the prequel to this article (read it online at thebark.com/dna), I had his ancestry tested with the Canine Heritage Breed Test. At that time, the company used 96 markers and tracked them to 38 breeds. A marker is a gene or DNA sequence on a chromosome that indicates “breedness.” The labs claim that the markers they use are 99 percent accurate.
In May 2012, when I began doing research for this follow-up article, I tested his DNA with the amplified Canine Heritage Breed Test again because it had been substantially improved to 400 markers and 120 popular breeds. I could have paid $25 to upgrade the 2008 test. But to be fair in my test-of-the-tests experiment, I submitted his cheek swab under a different name and without a photograph, just in case, as many people believe, the tests are a scam. In addition, I used the MARS Wisdom Panel Mixed Breed Identification Test. Mars looks at 321 markers and includes 185 breeds in its database.*
To analyze and compare the results fairly, I needed to find out if the tests were processed the same way, and I researched the history of the breeds identified in Chance’s ancestry.
Comparing the Tests
If a primary parent breed can’t be identified in the DNA, the program will look for a secondary grandparent breed, and so on and so forth, until it eventually clusters with a distant breed (if there is one). If there are no purebred ancestors, remnant breeds will be sought.
To identify markers that characterize a breed, labs take samples from multiple thousands of individual dogs representative of more than a hundred breeds. However, those dogs differ from one laboratory to the next. Although their sample sizes are big enough to absorb minor differences, no two dogs are exactly alike. Plus, line-bred dogs can affect results. For example, Labrador Retrievers bred exclusively for hunting may be more like each other than they are like the breed.
Finally, descriptive terminology differs. Canine Heritage uses primary, secondary and in the mix. Wisdom Panel uses parent, grandparent, great-grandparent and next best breed matches that include percentiles.
Because Chance has no purebred parent, his strongest signal would come from a purebred grandparent. One test indicated a Siberian Husky grandparent. However, the other two tests claimed he has no purebred parent, grandparent or great grandparent. In any case, all three tests concur that a combination of spitz breeds provides the strongest signals in Chance’s ancestry — Siberian Husky, Alaskan Malamute and, to a lesser degree, the Pembroke Welsh Corgi, a breed with some spitz lineage. Although it transmits a faint signal, the Pembroke Welsh Corgi is the only breed that showed up in more than one test. The white German Shepherd and blackand-tan German Shepherd, strong and weak signals respectively, are both named as ancestors and are admixtures of one another. Although they are herding dogs, it’s probable that both breeds have some spitz lineage. The Japanese Chin, a miniature Asian breed derived thousands of years ago from larger mastiff and spitz dogs, is also a fairly strong signal.
Large terriers make up the next strongest signals in his DNA. The German Pinscher, Standard Schnauzer and Doberman Pinscher are closely related. German Pinschers were used to develop the relatively new Doberman Pinscher breed. The Standard Schnauzer, originally called the Wire-haired Pinscher, is directly related to the German Pinscher. Sight hounds are mentioned in two tests. In the late 1800s, Borzois were likely mixed with Huskies to increase speed, and terriers were mixed with Italian Greyhounds.
The weakest signals, in some cases less than 2 percent of his makeup, include a ragtag group of breeds, including Border Collie, English Setter, Cocker Spaniel and Leonberger.
Making Sense of the Findings
The ancestral breeds named in the three tests seem absurdly disparate, but they are not contradictory. They all point to one truth: only a few degrees of separation differentiate Chance from all modern breeds. This is because most purebred dogs have a crippling lack of genetic diversity, which is the unintended consequence of modern breeding practices.
Except for 14 ancient breeds — Afghan, Akita, American Eskimo, Basenji, Canaan Dog, Chinese Shar-Pei, Chow Chow, Dingo, Finnish Spitz, New Guinea Singing Dog, Saluki, Samoyed, Shiba Inu, and Siberian Husky — all our modern breeds were developed in the last few hundred years.1 Although each has its own DNA fingerprint, they have so little genetic diversity that if you go back far enough, the DNA of almost every dog, mixed breed or purebred, will cluster with a few common ancestors. This finding raises the question, “How can breeds that look so different be so closely related.”
The complex DNA of stray mutts on the mean streets of, for instance, Lugazi, Uganda, or Zorzor, Liberia, may answer the question. Ubiquitous freeranging dogs living on the fringes of human settlement are not, as previously believed, semi-feral, mongrelized purebred dogs, but rather, are genetically distinct and subject to the pressures of natural selection. Some populations have been isolated for hundreds, if not thousands, of years. Subsequently the village dog genome remains complex and unabridged.
Suspecting that village dogs may be pure genetic remnants of ancient dogs, Adam Boyko, assistant professor in the Biomedical Sciences Department at the Cornell University College of Veterinary Medicine, co-founded the Village Dog Genetic Diversity Project with his colleague Carlos Bustamante, a genetics professor at Stanford School of Medicine.
The project is a worldwide collaboration of researchers, volunteers and veterinarians who gather canine DNA samples along with photos and information on weight, age, body measurements and coat color. The samples are analyzed at the Canine DNA Bank at the Baker Institute for Animal Health, part of Cornell’s College of Veterinary Medicine, which maintains a growing DNA archive of dogs worldwide.
The scientists believe their work will shed new light on when, where and under what conditions dogs were domesticated, and how dogs have adapted to human settlement, environmental stress and disease.
The first phase of the study included collecting samples from modern breeds, their mixed-breed relatives, breeds reputed to be from remote regions of the world and African village dogs. In 2009, they reported that African village dogs are a mosaic of indigenous dogs descended from more ancient dogs that migrated to Africa.2 Findings also indicated that their genome is being eroded at an alarmingly fast rate as they mate with recently introduced modern dogs. Researchers are now scrambling to find dogs in even more remote locations. In the summer of 2012, workers began collecting DNA samples in Liberia and the Democratic Republic of the Congo.
On a continuum, gray wolves, the progenitor of all dogs, have the most genetic diversity, and purebred dogs have the least. Village dogs’ diversity lies somewhere in between. Because purebred dogs are the result of strong selection for exaggerated traits, they have only a fraction of the genetic diversity displayed by village dogs. The genetic variant that underlies a desirable trait, whether it’s extreme size or intense behavior, has become fixed, wiping away not only competing variants but also variants associated with nearby genes.
Genes located close to each other on a chromosome are said to be linked, and tend to be inherited together or, conversely, wiped away at the same time. Thus, a trait that isn’t selected for can be wiped away simply as a result of being in the wrong place at the wrong time. If that trait happens to affect, for instance, immune response to disease, then that could be a problem.
By comparing the genome of village dogs to that of purebred dogs, scientists hope to be able to identify what’s been lost as a result of intense artificial selection. Dr. Boyko notes that “village dogs offer a chance to understand the mechanisms of certain genetic diseases. Knowing what those genetic variants are might be the first step towards invigorating genetic diversity in some modern breeds.”
The Significance of Canine Origin
Previous studies suggest that dogs originated in places as varied as Eastern Europe, China’s Yangtze River Valley and the Middle East. In a 2002 study, researchers pinpointed East Asia as the place of origin. However, some scientists think these dogs are descendents of an even older population that developed in a different place. Dr. Boyko’s findings confirm this. African village dogs have about the same amount of genetic diversity as those in the East Asian study, suggesting that both groups are the same age. It’s possible that both populations originated together somewhere else and then migrated to East Asia and Africa at about the same time.
To thoroughly complicate matters, the Canidae family does not play by the same rules as most other mammalian families. Unlike, say, horses and donkeys, dogs, wolves, coyotes and golden jackals can interbreed and produce fertile offspring. Consequently, following the genetic trail from domestic dog to wolf leads to a lot of stops and starts and many dead ends as well as plenty of headaches for evolutionary biologists.
A Multi-Disciplinary Approach
As Dr. Larson notes, “There has been so much admixture since dog domestication began, and especially in the last few hundred years, that looking at modern dogs is always going to be problematic. There may be modern populations that are less ‘corrupted’ or admixed, but even they will possess a legacy of several thousand years of crosses with large numbers of populations, and even wolves.” He adds, “The only way forward is to focus on other methods, including, but not limited to, ancient DNA from archaeological dog and wolf remains. And of course, there is the wider interpretation and understanding from lots of other fi elds to put it all in context.”
In the paper, researchers discussed an interesting pattern that emerges when sites with archaeological dog and wolf remains are overlaid onto maps showing the historical distribution of wolves. First, the archaeological remains are not found in the places where ancient breeds are believed to have been developed, intimating that dogs may have been domesticated multiple times from local wolf populations. Second, most of the ancient breeds come from areas where wolves never ranged, suggesting that humans had dogs as they migrated around the globe. Furthermore, dogs only appeared in these locations after agriculture was introduced.
The canine genome’s full story continues to evade scientists, but as DNA technology advances and analysis becomes cheaper and faster, researchers are optimistic that the answers they seek are right around the corner.
Will I continue to test my future shelter rescue mutts to find out who they are, even though I know that the answers will be the same — all modern dogs are so closely related that it’s almost impossible to discriminate ancestry? Probably. Other mysteries lie hidden in our dogs’ DNA. The idea that an animal can be morphed into so many extreme shapes and behaviors yet remain a simple combination of only a few stem parents is one of them.
We like to believe that scientific discovery advances tidily, fact by fact, to prove an irrefutable truth. But science is a messy business. And there is hardly a better example of just how messy than the search to tease out the mysteries hidden in the canine genome.
Good Dog: Behavior & Training
Seeking samples from you and your pets
The gut microbiome is a factor in a range of diseases such as cancer, inflammatory bowel disease and cancer, all of which are more common in Westernized populations of both pets and people. A new study called the American Gut Project is seeking to investigate how diet affects the gastrointestinal microbiome.
Previous work studying microbiomes of typical healthy adult humans raised questions about how their results apply to the entire population and to other species. Scientists with this project hope to collect samples from individuals with a full range of diets and lifestyles.
So far, research projects on this subject in dogs and cats include just a few small studies of lab animals or those that were ill. The fact that the American Gut Project will address the microbiomes in the intestinal tracts of large numbers of dogs (and cats) living in a variety of settings means that the results could yield useful information about the effects of diet, genetics, and lifestyle on the gut microbiomes of our pets. Such information may help us make informed decisions about how to feed and care for our dogs (and cats) in the future.
It is a goal of the project to collect samples from multiple individuals in the same household. If you want to participate in the study, along with your family members of the canine and feline variety, or if you want to learn more about the American Gut Project, click here.
Good Dog: Studies & Research
Q&A with Nancy Dreschel, DVM
Nancy Dreschel has long been interested in the ways people and animals interact. She got her degree in veterinary medicine from Cornell University, but her lifelong interest in behavior led her to return to graduate school five years ago to pursue a PhD in biobehavioral health at Penn State University. She, her husband and their two sons share their home with one dog, two cats, four fish and a mouse.
In her recent study, "Physiological and behavioral reactivity to stress in thunderstorm-phobic dogs and their caregivers,"* Dr. Dreschel investigated stress responses—pacing, salivating, panting, trembling, whining, hiding, increased salivary cortisol levels—of dogs with thunderstorm phobia and their human caregivers when both were exposed to simulated thunderstorms. Listening to a simulated storm elicited behavioral and physiological responses in nearly all the dogs, but not in their human caregivers. The way the dogs responded was not influenced by their caregivers’ reactions, or by how close the relationship was between person and dog. But dogs who lived with other dogs had less change in salivary cortisol levels and a more complete return to baseline levels by 40 minutes after the simulated thunderstorm than did dogs in single-dog households. Dogs in multidog households had slightly higher baseline levels of salivary cortisol. (For more, see “Is a Dog a Dog’s Best Friend?,” Jan/Feb 06.) The Bark recently interviewed Dr. Dreschel about her work.
Bark: How did you get interested in this subject?
Nancy Dreschel: My colleague Dr. Doug Granger, and the Behavioral Endocrinology Laboratory at Penn State are well known for their research on salivary hormone measurement, particularly in children. I was struck by the ease of saliva collection and thought that it would be a nice, noninvasive way to measure stress in dogs as well as in people. Thunderstorm phobia seems to be particularly frustrating for people and particularly stressful for dogs. I feel strongly about the humane use of animals and am interested in developing tools to measure stress in welfare situations.
B: How do you define stress?
ND: In order to define stress, I think you first have to understand that all aspects of living systems are [intended to be] in balance. Things constantly affect our physiological and psychological states, and our bodies respond to keep everything in homeostasis, or equilibrium. I define stress as being anything that knocks this off, including immune stressors (being exposed to a virulent disease), environmental stressors (being wet and standing outside on a 20-degrees-below-zero day) or mental stressors (enduring a thunderstorm if you are terrified of them).
B: Could baseline cortisol levels be affected by the difficulty that some people had in collecting the samples—wouldn’t the “phobic” dog demonstrate stress simply as a result of the collection process itself?
ND: Specimens collected on the control day did not show any increase in cortisol, which is what would be expected if the collection method itself caused stress. [On the control day, there was no simulated thunderstorm.] It should be noted that these dogs were behaviorally quite normal, other than their very specific fear of storms.
B: Are you familiar with any other studies that have measured the cortisol levels in multidog households?
ND: No—this was the first (and only) study I know of to measure cortisol in a home situation. Salivary cortisol has been measured in shelters and research facilities, however.
B: What sorts of clinical applications do you imagine could result from your research on dogs with thunderstorm phobia?
ND: Collecting saliva from dogs is a minimally invasive procedure that can be done by regular people in a number of different settings. I could see this procedure being used in studies of dogs with anxiety, in stressful situations and in welfare applications. I also think it could possibly be used to determine if dogs on medication for anxiety or fear are responding physiologically as well as behaviorally.
B: What kind of treatment program do you advise for people whose dogs have thunderstorm phobia?
ND: I recommend a number of individualized programs for dogs with thunderstorm phobia, including offering a “safe” place to go (covered crate, basement, etc.), behavior modification (counter-conditioning and desensitization), pheromone therapy and anti-anxiety medication. Many dogs require medication in order to calm down enough to be able to learn new behaviors.
B: What do you think is the most significant result of the study?
ND: I think the most significant result is finding the degree of increase in cortisol that these dogs experienced and the fact that it lasted so long. When I think of the number of dogs who experience similar stressors (which might range from a car ride to panic when left alone), I wonder if all these experiences are accompanied by a similar physiological reaction. We know by their behavior that some dogs become upset by certain situations, but these results show that a physiological response that could have adverse health effects is also occurring.
B: Why do you think the presence of other dogs in the household had an effect on cortisol reactivity in dogs with thunderstorm phobia? Is the higher baseline a key factor in the faster return to near-baseline levels?
ND: I’m not sure why living with other dogs had an effect in our subjects. Their baseline cortisol levels were somewhat higher to begin with, which could indicate they were under more stress on a regular basis. I think it is likely that something about living with other dogs mediates how their stress-response works. Maybe the day-to-day interactions better prepare the hypothalamic/pituitary/adrenal axis for response to major stressors.
I would emphasize that the dogs that lived with other dogs didn’t “seem” calmer—behaviorally, there was no difference. Because this was a fairly small study, it is hard to draw many conclusions about the multiple-dog findings.
B: Did the other dogs actually do anything to alleviate stress in these dogs?
ND: What struck me was a total lack of “comforting” as we define it in human terms, from the other dogs in the household. We think of comforting as having a shoulder to cry on, a hug, a gentle word or listening ear. Many of the dogs in our study (both those who lived with other dogs and those who were the only dog) sought out this type of comforting from their human companions. However, there was very little, if any, physical contact between the dogs in this study. Many of the non-subject dogs in the household weren’t even present during the procedure—the caregivers had isolated them in other rooms so they only had to deal with the subject dog.
B: Our magazine promotes adoption of shelter/rescue dogs, and likes to think that dogs benefit by living in multidog households (with compatible canines, of course). Is there any scientific basis for this?
ND: I think our research provides some evidence to support this statement. However, I do not recommend that people with storm-phobic dogs run out and obtain another dog, thinking that will make their dog’s problem go away. The dogs who lived in multidog households still had thunderstorm phobia and severe behavioral responses, despite the fact that they lived with other dogs.
*Published with co-author Douglas Granger, PhD, in Applied Animal Behaviour Science 95: 153–168.
Good Dog: Studies & Research
Of course they do
One of the hottest questions in the study of animal behavior is, “Do animals have emotions?” And the simple and correct answer is, “Of course they do.” Just look at them, listen to them and, if you dare, smell the odors that pour out when they interact with friends and foes. Look at their faces, tails, bodies and, most importantly, their eyes. What we see on the outside tells us a lot about what’s happening inside animals’ heads and hearts. Animal emotions aren’t all that mysterious.
When I first began my studies three decades ago—asking the question, “What does it feel like to be a dog or a wolf?”—researchers were almost all skeptics who spent their time wondering if dogs, cats, chimpanzees and other animals felt anything. Since feelings don’t fit under a microscope, these scientists usually didn’t find any, and, as I like to say, I’m glad I wasn’t their dog!
But now there are far fewer skeptics; prestigious scientific journals publish essays on joy in rats, grief in elephants and empathy in mice and no one blinks. The question of real importance is not whether animals have emotions, but why animal emotions have evolved. Simply put, emotions have evolved as adaptations in numerous species. They serve as a social glue to bond animals with one another and also catalyze and regulate a wide variety of social encounters among friends and foes.
Emotions permit animals to behave adaptively and flexibly, using various behavior patterns in a wide variety of venues. Research has shown that mice are empathic rodents, but it turns out they’re fun-loving as well. We also read accounts of pleasure-seeking iguanas; amorous whales; angry baboons; elephants who suffer from psychological flashbacks and post-traumatic stress disorder (PTSD—elephants have a huge hippocampus, a brain structure in the limbic system that’s important in processing emotions); grieving otters, magpies and donkeys; sentient fish; and a sighted dog who serves as a “seeing-eye dog” for his blind canine buddy. Today, the paradigm has shifted to such an extent that the burden of “proof” now falls on those who still argue that animals don’t experience emotions.
Many researchers also recognize that we must be anthropomorphic (attribute human traits to animals) when we discuss animal emotions, but that if we do it carefully, we can still give due consideration to the animals’ points of view. No matter what we call it, researchers agree that animals and humans share many traits, including emotions. Thus, we’re not inserting something human into animals; rather, we’re identifying commonalities and then using human language to communicate what we observe. Being anthropomorphic is doing what’s natural and necessary to understand animal emotions.
We might expect to find close, enduring and endearing emotional relationships between members of the same species, but improbable relationships also occur between animals of wildly different species, even between animals who are normally predator and prey! Such is the case for Aochan, a rat snake, who befriended a dwarf hamster named Gohan at Tokyo’s Mutsugoro Okoku Zoo, and a lioness in northern Kenya who adopted a baby oryx (usually an appetizer before a larger meal) on five different occasions.
It’s bad biology to argue against the existence of animal emotions. Scientific research in evolutionary biology, cognitive ethology (the study of animal minds) and social neuroscience support the view that numerous and diverse animals have rich and deep emotional lives. (Here I focus on mammals, although there are data showing that birds and perhaps fish experience various emotions as well as pain and suffering.)
Charles Darwin’s well-accepted ideas about evolutionary continuity—that differences among species are differences in degree rather than kind—argue strongly for the presence of animal emotions, empathy and moral behavior. Continuity allows us to connect the “evolutionary dots” among different species to highlight similarities in evolved traits, including individual feelings and passions. All mammals (including humans) share neuroanatomical structures, such as the amygdala and neurochemical pathways in the limbic system that are important for feelings.
Mirror neurons help explain feelings such as empathy. Research on these neurons supports the notion that individuals can feel the feelings of others. Mirror neurons allow us to understand another individual’s behavior by imagining ourselves performing the same behavior and then mentally projecting ourselves into the other individual’s shoes.
To what degree various species share this capability remains to be seen, but there is compelling evidence that humans are not alone in possessing it. Diana monkeys and chimpanzees help one another acquire food, and elephants comfort others in distress. Mirror neurons also help explain observations of rhesus monkeys who won’t accept food if another monkey suffers when they do so, and empathic mice who react more strongly to painful stimuli after they observed other mice in pain.
The borders between “them” and “us” are murky and permeable, and the study of animal emotions helps inform the big question of just who we are. Another big question for which answers are revealed by studying animal passions is, “Can animals be moral beings?” In my development of the phenomenon that I call “wild justice,” I argue that they can. Many animals know right from wrong and live according to a moral code.
When people tell me that they love animals because they’re feeling beings and then go on to abuse them, I tell them that I’m glad they don’t love me. I often ask researchers who conduct invasive work with animals or people who work on factory farms, “Would you do that to your dog?” Some are startled to hear this question, but if people won’t do something to their own dog that they do daily to other dogs or to mice, rats, cats, monkeys, pigs, cows, elephants or chimpanzees, we need to know why. There’s no doubt whatsoever that, when it comes to what we can and cannot do to other animals, it’s their emotions that should inform our discussions and our actions on their behalf.
Emotions are the gifts of our ancestors. We have them, and so do other animals. We must never forget this. When it comes to animal welfare, we can always do better. Most of the time, “good welfare” is not good enough.
Copyright © 1997-2017 The Bark, Inc. Dog Is My Co-Pilot® is a registered trademark of The Bark, Inc