News: Guest Posts
They’re not so different than cats after all
I love research that reveals surprising similarities between species, especially species often depicted as rivals. Last year, when MIT researchers “discovered” cats had a sophisticated and speedy mechanism for drawing fluid into their mouths, which was one reason they aren’t as sloppy as canines, it just seemed like one more example of the old cats are sleeker, neater, smarter argument.
The thinking was that dogs scooped fluids into their mouths with a backward-curled tongue action. But thanks to weirdly-watchable x-ray videos of dogs drinking, Alfred Crompton and Catherine Musinsky have revealed the dogs do lap like cats. (“How dogs lap: ingestion and intraoral transport in Canis familiaris” published in The Journal of Royal Society Biology Letters—abstract free; fee for full report.)
Both dogs and cats use a method called adhesion. “Liquid is transported through the oral cavity to the oesophagus, against gravity, on the surface of the tongue as it is drawn upwards, then a tight contact between the tongue surface and palatal rugae [ridges on the roof of the mouth] traps liquid and prevents its falling out as the tongue is protruded.”
According to a story on Wired’s blog, the commonality goes back to a shared ancestor 43 million years ago. Since that time neither cats nor dogs evolved the thick cheeks now present in many other animals, including humans. “Such cheeks form a tight seal that both retains liquid and allows suction-powered drinking. Without them, cats and dogs needed to develop a different way to drink.”
While the research could impact robot design, it probably won't improve cat-dog relations.
News: Karen B. London
A new study of canine locomotion
Many studies of locomotion in dogs focus on sick dogs while others focus on particular aspects of locomotion. The recently published book Dogs In Motion includes the comprehensive findings of a study of more than 300 dogs and how they move. More than 30 breeds were studied with several techniques helping reveal how dogs move.
Researchers Dr. Martin Fischer and Dr. Karin Lilje used high-speed x-rays as well as infrared imaging based on reflective dots positioned on the dogs to record details of their movements from both the side and from the front. Interestingly, researchers found that no matter what breed of dog was looked at, the patterns of movements match. Though the gaits of many breeds may appear quite different, the underlying motions of bones, muscles and connective tissue are not so different after all.
The study shows that displays and textbooks sometimes have errors, particularly related to the heights of corresponding parts of the front and hind limbs. The shoulder blade and hip are often depicted at the same level, when the true placement of these joints is actually different. The thigh and the shoulder blade correspond, as do the upper arm and the lower leg. According to Fischer, the shoulder blade and forearm are moving in matched motion with the thigh and middle foot, even though that is different than what was previously thought.
Previous investigations into the ways dogs move, such as Rachel Page Elliot’s Dogsteps, have changed what people thought they knew about canine locomotion, and this most recent study is one more scientific study that does so.
News: Karen B. London
Who is peeing and where?
Urine marking in dogs is a well-known behavior in the sense that everyone is aware that it happens, but it is poorly known in the scientific sense because so few studies have examined it with a rigorous approach.Scientists Anneke Lisberg and Charles Snowdon applied such needed rigor to the subject and report the results in “Effects of sex, social status and gonadectomy on countermarking by domestic dogs, Canis familiaris,” which was recently published in the journal Animal Behavior. Countermarking behavior in dogs consists of either marking on (overmarking) or near (adjacent marking) previous scent marks. Part of what’s so great about this study is that it shows that what we think we know about behavior from observing it casually, even over years and years, may not be as spot on (so to speak) as we think. As is so often the case, a controlled study of the relevant variables revealed that what is going on is significantly more complex than previously believed. Lisberg and Snowdon’s study is one of a few to examine canine urine marking and as such makes a big contribution to our understanding of this behavior. Here’s what their study found: In an experiment with urine from groupmates and from unfamiliar dogs presented to dogs in a controlled way on sticks, they found that: Intact males (but not neutered males) were more likely to overmark urine from intact females. Males who overmarked had a higher tail base position (which the authors used as a measure of social status) than males who did not overmark. Familiarity with a dog did not affect overmarking of its urine, but dogs adjacent-marked only urine samples from unfamiliar dogs. Neither sex nor tail base position affected adjacent marking. Being spayed or neutered had no relationship with the likelihood of countermarking. In observations of countermarking at a dog park, they found that: Males and females both countermarked and investigated urine. Males and females with higher tail base positions did more urinating, countermarking, and investigating of urine than members of their same sex with lower tail base positions. Lisberg and Snowdon conclude that although intact males may be overmarking intact female urine as a form of mate guarding as has long been suspected, that is only a piece of the story. Both sexes, whether intact or not, appear to countermark in a competitive manner. Additionally, this study suggests that overmarking and adjacent marking may have different functions. What have you observed about your dog’s marking behavior?
News: Guest Posts
C.D.C. study: Pets can be dangerous bedfellows.
Why does someone always want to rain on the parade? Here are countless people and pets—my household very much included—enjoying perfectly wonderful and healthy nights together, when some buzzkill at the Centers for Disease Control and Prevention starts throwing around zoonoses and pathogens, even bubonic plague!I read about the C.D.C study warning about the risks of pets in your bed in The New York Times and wondered, don’t these researchers have anything better to do? I can’t believe that the “risks” outweigh the emotional and physiological benefits of keeping our pets close. I’m all for precautions, as much for my dogs as for me. No fleas or ticks allowed. No licking wounds. No biting. No open-mouth kissing. If anything worries me, it’s the sleep I lose on nights when the dogs are stealing the covers or inching too far into my real estate. For that, they get kicked to the curb.
News: Karen B. London
What does it mean?
A graduate student studying the diet and nutrition of people living in Texas between 1,000 and 10,000 years ago has found evidence that those people were eating dog meat. Samuel Belknap III was sorting through dried human waste and found a bone that DNA tests suggest came from a domesticated dog, not a fox or wolf. The bone was found in a pile of human excrement and had the orange-brown color typical of a bone that has passed through someone’s digestive tract, which is why the reseachers think their find shows that people were eating dog meat.Although it is unappealing in our culture to eat dog meat, especially among dog lovers, it’s really not so surprising that people in Texas thousands of years ago were doing so. In Central America during that time period, many people ate dogs, and across the Great Plains, many people did so when food was scarce. Eating the meat of dogs is widespread today, though it is not common in Western culture. Additionally, many of us who cringe at the thought of dog meat do eat the meat from other domestic animals such as cows, sheep, goats and chicken. Carbon-dating suggests that the bone in question is 9,400 years old, and thus is the oldest evidence of domesticated dogs in the Americas. The next oldest finds were of dogs from around 8,000 years ago. Evidence of domestication from archaeological records goes back over 30,000 years in Belgium, 26,000 years in the Czech Republic and as far back as 15,000 years in Siberia. On this side of the Atlantic, the records are less detailed and do not extend as far back as in other areas of the world. There are some concerns regarding the study such as the possibility that the dog was consumed by some other animal other than a human, and that the DNA testing on such a small bone fragment may not be accurate. The piece of bone is 15 millimeters by 8-10 millimeters, which is roughly the size of a pinky fingernail. The bone has been identified as a fragment from where the skull and spine connect. The full article on this discovery will be coming out in the American Journal of Physical Anthropology later this year.
News: JoAnna Lou
C-BARQ provides data for valuable research
Recently, I attended a presentation of Parvene Farhoody’s research on the physical and behavioral effects of spaying and neutering, which is currently being prepared for publication. There were a lot of interesting findings that I can’t share until they’re published (I promise to do so when they are!), but I did learn about an important database.
Parvene’s research was based on analysis of data from C-BARQ, a database developed by researchers at the Center for the Interaction of Animals and Society of the University of Pennsylvania. It’s the only behavioral assessment instrument of its kind to be extensively tested for reliability and validity on large samples of dogs. Currently, there are more than 14,000 dogs in the database.
The assessment consists of 101 questions that describe the different ways in which dogs typically respond to common events, situations, and stimuli in the environment. Even better, anyone can submit their dog’s assessment. The interface is easy to use and takes about 10-15 minutes to complete.
C-BARQ is fun because after you’re finished, you can see how your dog’s behavior compares to other dogs in the database. Though you can only take the results with a grain of salt, it’s interesting. I wasn’t surprised that Nemo scored gold stars (the symbol for scoring in the good to average range) for most behaviors and scored two red flags (the symbol for scoring less favorably than at least 90 percent of the sample) for begging. However, I was surprised that Nemo scored one red flag (the symbol for scoring less favorably than at least 75 percent of the sample) for trainability. Nemo has always been an easy dog to train!
Nonetheless, C-BARQ is an important resource. The data from C-BARQ contributes to many research studies that will help us better understand our dogs, so I encourage you to take the time to fill out as assessment for each of your pets.
News: Karen B. London
It goes way beyond a big vocabulary
[Editor's update: A February 9 episode of Nova will feature Chaser.]
In a recent study in the journal Behavioural Processes, John W. Pilley and Alliston K. Reid have demonstrated an impressive level of language ability in a Border Collie named Chaser. It’s certainly easy to be most impressed by the fact that she knows the names of 1,022 objects, which she was taught over a nearly three-year period. Yet, from a scientific point of view and especially for scientists who study language acquisition and cognitive abilities, that is not as interesting as the other conclusions from the study “Border collie comprehends object names as verbal referents.”
These scientists who studied Chaser also conclud that she can distinguish between the names of objects and commands. In other words, she understands that names refer to objects, regardless of the action she is told to perform to those objects. She was asked to either nose, paw or take one of three toys in an experiment, and could successfully do so. Years ago, the study of a Border Collie named Rico amazed the world with reports that the dog had a vocabulary of over 200 words, did not demonstrate this ability. Though Rico may have been able to do so, the experimental design did not allow a definitive conclusion. Pilley and Reid also concluded that Chaser understands categories of objects such as “ball,” “Frisbee” and “toy.” When asked to retrieve an object of one of these types, she was successful at choosing an item from the correct category. She is familiar with many items in each group. Interestingly, “balls” and “Frisbees” are categorized based on overall shape, but “toys” are those objects she is allowed to play with as opposed to those with which play is forbidden. The function, but not the form, of toys and non-toys is distinct. The final conclusion in the study was that Chaser can learn the name of a new object by inferential reasoning by exclusion. That is, she can learn the name of a new object based on the fact that it is the only novel object in a group of objects whose names are all already known by her. This kind of learning cannot be based on associative learning mechanisms because the novel name and the novel object are not presented together. What do you think about this study and what does it make you wonder about your own dog?
News: Guest Posts
Harvard brains miss a trick
I recently read about and then signed up for a happiness study conducted by Harvard researchers. I answered some personal questions and then agreed to respond, as soon as possible, to a daily (you can request more frequent check-ins) text and email. The short daily survey asks several questions about what I’m up to and how I feel about it, and then charts my emotional temperature.But I’ve hit a stumbling block. Recently, the survey dinged me during a lovely, long walk with my dogs. Feeling good! I reported. Then the survey asked if I was alone. Well, no. Then, it asked if I was interacting with someone. Well, yes. Although I admit at that point I started to feel a little nervous about my answer. But then, the next question came: Are you interacting with 1, 2, 3 or more people? People? I longed for an “other” at the very least. But I had no chance to explain. I selected “2 people.” All those years of study, math camps, tutors, slide rules, pocket protectors and advanced degrees, and these Ivy Leaguers forgot about companion animals in a study to gauge happiness? What were they thinking? When I consider the high points of my day, many times it’s spent directly interacting with my dogs. I love people too, especially my husband, but playing, walking, training, cuddling with my dogs is often pure pleasure. Hopefully the study, which appears to be dynamic, will change and begin to include these important relationships in the metrics of happiness. Otherwise, the results wil be incomplete.
News: JoAnna Lou
New study suggests social animals developed larger noggins
Ask a cat lover and a dog lover which species is smarter and you'll get two different answers.
As a dog lover myself, you can guess my opinion, though what do I know, apparently a study in the United Kingdom found that the average cat lover holds a higher education than the canine persuasion! But, smarts aside, the truth is that dogs have larger brains, and not because they’re generally bigger.
A new study by Oxford University shows that canines have larger brains than felines because they are a highly social species. While researchers were mapping the evolutionary history of the brain across more than 500 different mammals, they found that there is a link between the sociality of animals and the size of their brains relative to body size.
The brains of monkeys grew the most over time, followed by horses, dolphins, and dogs. The brains of solitary animals, like cats, grew much more slowly during the same period. The study suggests that social animals may have developed larger brains because group living is challenging--now I can see why humans have such large brains!
News: JoAnna Lou
Can implanted identification cause cancer?
Last week, the tragic story of Target the war dog hero sparked a discussion among our readers about microchips and the possible risks. A couple of people asked about the research behind the risk claims, so I decided to explore the topic. This discussion is particularly timely because Merck was recently served with a lawsuit over claims that its HomeAgain microchip caused cancer in a Massachusetts cat named Bulkin.
Unfortunately there are no large-scale, statistically valid experimental studies involving microchip implants in dogs, so we don’t know their long-term safety for sure. However, there have been a handful of studies with laboratory rodents, which is a start.
In six different studies with mice and rats, ranging from 1996 to 2006, it was reported that 0.8 and 10.2 percent of the animals developed malignant tumors around or adjacent to implanted microchips. It’s a wide range, though the majority of studies had a 1-2 percent tumor rate. The studies also had a wide range of sample sizes, which may help account for the variation in findings.
Nonetheless, based on the rodent studies, it does seem like there is a small chance that microchips are linked to malignant tumors. Considering that millions of dogs have microchips, the fact we haven’t seen an epidemic of microchip-related cancer confirms that the percentage is probably very small.
However, as any dog lover knows, statistics mean nothing when your pet is the one affected. The cancer risk has been particularly interesting to me since I'll be adding a new puppy to the family soon and will have to make the microchip decision. Both of my current dogs are micrchipped and it's always given me peace of mind, particularly since they are not allowed to run at USDAA agility trials with their collars on. Knowing the possible risk, I will be sure to monitor the shoulder blade area (where my pups have their microchips) for any changes to the skin.
No form of identification is flawless and none of them is guaranteed to bring your pup home. It’s up to you to weigh the risks and the benefits and decide what is best for your pet.
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