Hundreds of observations of animals in the wild suggest that they sometimes self-medicate, ingesting plants or other substances with medicinal actions to make themselves feel better. As a veterinarian with decades of experience treating animals that eat all the wrong things, I find this idea intriguing; are these episodes due to coincidence, instinct, or a sophistical knowledge of herbal medicine? And how do they know what would help what ails them?
In a book called “Wild Health”, author Cindy Engel cites hundreds of observations in which elephants travel hundreds of kilometers to find herbs that help with birthing and chimpanzees ingest clay to settle their upset stomachs. Engel’s conclusions are doubtlessly exaggerated, as she seems to believe every claim advanced by folk medicine or herbal practitioners, but many of these observations have held up to scientific scrutiny. If we knew how animals choose their own treatments, maybe it would change how we medicate our pets (and ourselves).
Simple association seems like the place to start in order to understand self-medication. If it feels good, do it. (Pardon me while I self-medicate with my morning cup of coffee!) When a chimp has a stomach ache after eating too much of a fruit that contains a low level of a toxin, eating a several mouthfuls of clay would help coat the stomach and intestine and absorb the toxin, relieving the intestinal distress. (The kaolin in Kaopectate is a form of clay used to settle the stomach, although recent studies suggest that it isn’t very effective) . Regardless of why the primate first tried the “clay cure”, the association of eating clay and feeling better would reinforce this self-medicating behavior. The inverse is known to be true as well: Eating something that makes the animal (or person) sick will often cause an “acquired food aversion” so that the mere smell of the item causes a loss of appetite. This reaction apparently does not require a conscious association between ingestion and nausea, although it is reasonable to assume that an intelligent animal would also remember that they were sick after eating a particular food. Sheep farmers have used thisprinciple to discourage coyotes from attacking their flocks; a dead sheep is laced with lithium (which causes intense nausea and vomiting) and left where coyotes are likely to feed. After getting sick on mutton, the coyotes avoid sheep and concentrate on the rabbits and rodents that form their natural diet.
If an association between eating something and feeling better is an obvious answer, a new question arises: What if the self-medicating animal chooses something that has an unpleasant taste or sensation, but cures some illness days later? Wouldn’t the animal associate the immediate unpleasantness of chewing a bitter herb with illness, rather than cure? My guess is that individual animals vary widely in their willingness to experience something unpleasant in return for “delayed physical gratification”. Many pet owners tell me that their dog or cat takes their medication willingly, as if they knew that it was going to make them feel better. On the other hand, most animals will do their best not to take their drugs, even when it will make them feel better eventually. It is possible that the time that elapses between the medication and the physical improvement is critical; if taking a bitter pill today makes the animal feel better the next day, the association is stronger than if a week of medication is required before improvement. (These same principles apply to humans; a recent study found that nearly half of the people prescribed medications for serious chronic diseases failed to take their medicine. Perhaps they just couldn’t tell that it made them feel better, even though they may have understood the purpose of the medication intellectually).
Another consideration is that the body can sometimes make these associations better than the brain. When mice with a fatal genetic immune disease are given their immune suppressive drugs flavored with the distinctive taste of saccharine for several weeks, then their disease can be controlled with saccharine alone. Apparently the renegade immune cells themselves “remember” the association between the taste of the artificial sweetener and the effect of the drug.
There could also be a cultural component to self-medicating in wild animals. The most credible observations of animals taking their own cures are from elephants and chimpanzees. Not only are these species well-studies (due to their appealing, human-like traits), but they are also highly social animals in which cultural transmission of behaviors is known to occur. If your mom tells you to “take this and you will feel better”, then you do it—even if you are a chimpanzee.
Do our pets show evidence of self-medicating? There are several well-known examples of dogs and cats seeking things that might make them feel better. Cats will often lick bricks or eat cat litter when they are anemic, and we assume that the body “wants” more iron-containing minerals to build up the number of red blood cells. Although this makes some sense in the wild (where poor diet might be a cause of anemia), pets certainly get all the iron they need from their food, and anemia in cats and dogs is almost always caused by other diseases that can’t be helped by eating more iron. But the body doesn’t know that it has Autoimmune Hemolytic Anemia, it just knows that the blood is too thin. Similarly, eating grass is a common behavior when a dog has an upset stomach, but it usually just makes things worse and causes vomiting. In the wild environment, throwing up intensely for a few days might be lifesaving when a wolf eats a bit of toxic, spoiled deer meat, but In domestic dogs purging on grass is likely to delay recover from routine stomach upset. These common behaviors are likely hard-wired physiologic responses shaped by evolution for the wild environment, and not “self-medicating” actions learned by association.
A recent study was done to determine the frequency of the many various causes of stomach upset in dogs. The conclusion was that the great majority of all acute intestinal problems in dogs were due to eating all manner of irritating, toxic, fat-laden, and spoiled materials. Perhaps if they lived in the wilderness there would be less bad things for them to get into, and maybe they could find the right herbs to settle their stomach when they needed it.
What is it worth? This is a judgment that humans make many times a day. “Is that dress really worth $120?”, “Should I sell that ratty old chair on Craigslist or just give it away?”, or “Should I put my tax refund in the bank, or treat myself to a day at the spa?”. We know that dogs’ minds are full of their own concerns, but sometimes they make judgments similar to human economic decisions.
Every dog owner is familiar with the most basic canine transaction: “paying” the dog with a treat when it complies with our request to “Sit”. It is easy to dismiss this simple exchange as a conditioned response that requires little thinking and no negotiation, but sometimes dogs reveal a more sophisticated understanding of economics.
One of my patients had a habit of bringing sticks and other objects in from the yard to play with in the house. At first this seemed harmless enough, but one day Max brought in a particularly muddy piece of wood. Rather than chase after the dog to retrieve the stick, his owners offered the dog a food treat and traded it for the dog’s dirty treasure. This got the dog’s attention, and every time Max went out he would bring in some small object and carry it around until he was offered a dog cookie in exchange. Eventually the owners realized that they had effectively trained the dog to collect objects for barter, so they decided to stop rewarding the Max’s collecting habit. At first the dog was confused: “Why are they no longer willing to trade?”, he wondered. Then he started bringing in larger and larger objects. The owners continued their “no payoff” policy, and the dog escalated his efforts by bringing larger and larger sticks; still no cookie. Eventually the dog dragged in a decaying log 3 inches in diameter and 5 feet long, dropping it ceremoniously in the middle of the living room as if to say “At least THIS should be worth a cookie!” When the owner relayed this story to me, I realized that the dog showed a definite sense of relative worth: a big stick is more valuable than a small one, and it should be worth more in trade. Pretty sophisticated economics.
This keen sense of relative worth backfired for another of my patients. Josie was a Labrador Retriever, and she loved her Milk Bones. If they gave her small dog biscuits, she ate them up enthusiastically. But if they gave her the same treats in the big dog size, she was clearly conflicted and frustrated. Josie would carry it around and whine, but she wouldn’t eat it. Eventually she would ask to go outside and she would bury her prize in the ground. The owners really wanted Josie to enjoy these treats, so they refused to let her outside as long as she was carrying the biscuit. Soon they found that she would stash the cookie somewhere in the house, and the next time they opened the door to let her out Josie would rush to retrieve the treat from its hiding place and run out to the yard and bury it. Apparently she was responding to some feeling that anything this big was valuable should be saved for the future, rather than swallowed for momentary pleasure. This dog was a victim of her compulsion to save particularly valuable treats, and Josie’s owners learned to give her only small bite-size biscuits that she could enjoy right away.
Trainers make use of this idea of low-value and high-value treats. When a reward is offered for a task that has already been learned, a small treat of relatively low value should be used (and sometimes a “Good Dog” is a sufficient reward). But when a difficult or new task is requested, high value treats (a small piece of cheese, rather than a small dog cookie) may be more motivating. When teaching the dog to “Come”, or to keep his attention while passing another dog on the sidewalk while on leash, we need to make it worth their while.
Nearly every day I have the “Quality of Life” discussion with a client about their beloved pet. Near the end of their dog or cat’s life, people sincerely try to discern whether their pet would choose to continue living with their diseases and disabilities. A veterinary Quality-of-Life scale (QOL) has been devised, assigning 10 points each to categories that include Hurt, Hunger, Hydration, Hygiene, Happiness, Mobility, and More Good Days Than Bad. An arbitrary threshold of greater than 35 points suggests that life is still worth living. (There is also an official QOL scale for humans, including 16 items. This QOL score is used when studying the effectiveness of treatment for serious diseases).
One thing that is missing from these QOL scales is Cognition. I can only speak for my animal patients, but I often notice that older pets that are senile and confused experience more suffering from the same physical maladies than do mentally competent dogs or cats. Admittedly, I am guessing what the animal’s experience might be like by observing their behavior, but comparison to normal dogs and response to various types of treatment often confirms this impression.
For example, most older large breed dogs experience some degree of discomfort from hip arthritis or back problems as they get older. My first question for the owner of a geriatric canine is “How hard is it for him to get up when he is laying down?” The usual answer is “It takes him a minute to get up, but once he gets moving he does pretty well—especially if there is a dog treat involved!” When I see the old Laborador with Cognitive Dysfunction (the canine version of Alzheimer’s), the dog may have the same difficulty rising and may walk as well once he gets moving, but it is obvious when you look at the old guy that he is much more anxious about the discomfort that he is experiencing. There is likely to be more whining, more panting, and a reluctance to repeat the experience if the dog is senile. Perception of pain is largely a function of the brain and dementia can take away the brain’s ability to cope with discomfort.
When I have a Quality of Life discussion with a pet owner, we look at both the pain and the pet’s ability to cope with it. In some cases, treating the pain may be enough: the patient is still confused, but has less to cope with. In other cases we can treat the anxiety and the brain’s perception of discomfort with antidepressants or other treatments. We have few remedies to improve the function of the failing brain, but some improvement can be achieved with diets, exercise, and nutritional supplements. Improved mental alertness does seem to improve the QOL, even when the disease or disability persists.
As our understanding of the brain has increased, neuroscientists are willing to venture into territory once reserved for philosophers and artists. Academic controversy currently rages over whether “the arts” have any evolutionary value to humans or are simply an accidental by-product of an overly developed brain. No less an authority than Stephen Pinker, world-class brain explainer from MIT, claims that music has no particular value to the well-being of human beings, but other biologists (as well as common sense) insist that the arts must confer some sort of survival or reproductive advantage to our species.
When the question of art’s value is turned to animals, most neuroscientists head for cover, while others repeat the familiar refrain of “Man is the only animal who . . .”. Although I am neither a philosopher or a qualified neuroscientist, I have spent a lifetime listening to the stories of observant pet owners, and I can offer some tantalizing anecdotes that suggest some form of artistic endeavor in dogs, cats, and birds. You can decide for yourself what these observations mean.
The first two stories are strikingly similar. Years ago my brother told me how his Labrador Retriever would take pieces of firewood from the storage shed and arrange them in the yard. Each piece of wood was placed perpendicularly to a previous piece, and the process was repeated until the entire yard was covered with a domino-like pattern of split pine chunks. There appeared to be no discernable reason for this behavior, but many hours were spent restacking the firewood each time the dog repeated the behavior.
One of my clients offered a similar story about his Husky. The dog also arranged pieces of firewood, but in a circular pattern 20 feet in diameter, with each piece of wood pointing toward the center of the circle. The dog’s owner described it as his “Doggy Stonehenge”, and the purpose was as inscrutable as the famous stone circles of antiquity. It seems that both these stories suggest that the dogs simply enjoyed creating a pattern with objects that were at hand. Whether there is a “meaning” to these creations, or whether they simply reflect the use of pattern-recognition functions of the brain could be open to question. Many philosophers of art claim that the inherent beauty of art should be independent of any ascribed meaning or representation.
There was certainly meaning in the behavior of one of my cat patients. This cat was mostly an indoor cat, but when he took his morning walkabout he often caught a mouse, presenting it proudly to his owner when he returned. The cat’s owner was not impressed, and promptly disposed of the cat’s catch. He described the cat reacting as if it was insulted at the way the gift was received. One day the owner walked out of his house to find 6 very large dead rats arranged in parallel positions down the middle of the walkway from the front door. Each rat was spaced an equal distance from the next, and this array of dead rodents made it impossible to walk out the door without stepping on a rat. To the owner, there was a clear message of injured pride and “I’ll show you!”. We can’t know what this cat was actually thinking, but the pattern was striking and stimulated a strong reaction in the human observer.
At one time I raised parrots, and my favorite were the small green and gray Quaker Parrots. These hardy and intelligent birds are unique among parrots because they build elaborate nests of sticks and twigs. These nests are used year-round, and serve as both shelter and a place to incubate eggs. Dozens of pairs of Quaker Parrots may build connected nests in a huge “apartment complex”, and the workmanship of the interwoven twigs is remarkable. My breeding parrots were housed in large outdoor cages, and I provided wooden next boxes, hinged on the back so that I could check the progress of the eggs within. Because I knew that the birds would want to add their own work to these artificial nests,. I installed a broad “porch” of wire mesh in front of the nest opening and provided lots of twigs for additional construction. The birds clearly enjoyed using the small sticks to surround the nest opening, as well as to contour the inside of the nest. One of my pairs had a different architectural vision, however. This pair sealed over the front entrance to the nest box and chewed a hole in the floor of the box. Then a beautiful downward-curving “spiral staircase” was constructed with twigs, so that the birds could enter the nest from below. This seemed to satisfy them, but when they laid 3 white eggs in the spring, each egg rolled down this chute, breaking on the cage floor. After the third egg broke, the birds tore out the entire curved structure. Within a week they had rebuilt it, but to the same specifications. Again they laid eggs, and again the eggs rolled out the bottom of the nest an broke. Once more the birds tore out the bottom entrance to the nest, but this time they rebuilt it using the original front entrance and sealing over the hole in the floor. Did they build the “spiral staircase” for aesthetic reasons, but yield reluctantly to practical considerations? I doubt that even the birds knew.
Evolutionary biologists naturally look for some advantage that “artistic” humans or animals might enjoy to justify the costs of creativity. Perhaps art shows that the artist is able to discover patterns in the environment which improve survival. Perhaps creating something new and different attracts the attention of potential mates. Or maybe the intelligent brain just needs something to do.
As recent as twenty years ago, scientists insisted that man is the only animal that shows a preference to use one hand (or paw) more than the other. This “hemispheric dominance” was tied to the human development of language, which redeveloped space in the left cerebral hemisphere. Animal psychologists had tested all sorts of creatures for “handedness” by observing which hand or foot was used for simple tasks like pressing a lever or picking up a piece of fruit, and no preference was evident for either right or left.
It turns out that scientists were misled by teaching animals to do things that were so simple that they could be done with either side. This insight came from observing monkeys at a primate sanctuary in Japan. Oranges were thrown across the water to monkeys confined to a small island. The animals gathered up their favorite fruit with either hand. But when an orange landed in the water, the monkeys would devise ways to reach it by hanging on to a bush near the water’s edge with one hand and leaning over to pick up the fruit with the other hand—always their right hand!
It makes sense that the more difficult the task, the more the brain should concentrate its resources. By developing a preference to use one side of the brain for a really critical task, time is not wasted trying to decide which hand to use.
Following this line of reasoning, I did an informal study many years ago of cats that were presented to our hospital for bite wounds on their front paws. This is a common occurrence, presumably because angry cats often take a warning swipe at a feline adversary and don’t always avoid the sharp teeth of their opponent. These wounds are painful and always become infected, so our medical records contained almost a hundred such injuries. Upon investigation, 90% of these wounds were on the right front leg, suggesting that most cats were right-pawed, at least for something as demanding as fighting. In my survey, 6 of the 8 injuries to a left paw were to the same cat; not only was this guy a lefty, but he must have been a really slow southpaw!
Scientists now widely accept the idea that hemispheric dominance (mostly right-sided) occurs in many species. An article in Scientific American magazine last year detailed how biologists can identify a preferred side for important activities in nearly every vertebrate species, including schools of small fish (which reflexively dodge to the right when a predator suddenly appears).
The “handedness” preference of various animals has become a legitimate subject for study, but the results still vary depending on how the question is investigated. Dogs were asked to step down from a box to see which foot reached out first. In this study, most male dogs led with their left, while females preferred the right, although this may not have been a task with enough challenge to prove that the sexes are wired differently. Previous studies had shown that dogs wag their tails faster in one direction when they are excited to approach a person, and in the other direction when they are apprehensive.
Many other animals have been studied. Cats showed a male/left paw, female/right paw similarity to dogs, but these laboratory studies were not as demanding as the cat fight survey. A recent article in a veterinary behavior journal studies horses hoof use by attaching pedometers to all of the feet to see which side was used the most. Most horses used the left side more than the right, and this was correlated with the direction of the circular whirl of hair in the middle of their foreheads. Apes have shown definite “handedness” in dozens of studies.
Although the study of hemispheric dominance may not have a lot of practical application when it comes to teaching Fido to “stay”, it raises interesting questions about how our pets’ brains function, and reminds us that we all have lots more to learn about each other.
There are certain types of dogs that people keep for the same reasons that they keep a loaded gun. These reasons lie at opposite ends of the spectrum of society: at one end, people who feel so threatened by the world around them that they need serious protection to prevent becoming a victim, and at the other end, people who want to cast a shadow of intimidation. This commentary is not about the Second Amendment or Dangerous Dog Laws. It is simply an observation about people who gravitate toward certain breeds of dogs.
After World War II, the German Shepherd Dog was the “loaded gun dog”. Memories of the German Gestapo and Storm Troopers made the German Shepherd Dog synonymous with menacing “police dog”. But then came Rin Tin Tin, hero of early TV, to put a heroic face on this classic breed. The Doberman Pinscher (also a German creation) inherited the mantle of vicious guard dog, and when one of these black-and-tan canines showed up on the TV screen it was usually accompanied by ominous music. Dog owners that wanted to walk down the street with an air of “don’t-mess-with-me” chose the Doberman, cropped ears and all. The problem was that most Dobermans are actually gentle pets that are rarely aggressive unless they have attack training. In the 1980’s, the Rottweiler took over as the intimidator, and their reputation was often deserved. (Another German breed—is there a trend here?). I have treated hundreds of Rottweilers that were great dogs, but when I ask the owners to put medication in the dog’s ears or clip its toenails they look at me helplessly, as if I had asked them to yank off Superman’s cape. Rottweilers often deserved their reputation, but eventually they lost the title of Official Loaded Gun Dog to the Pit Bull. Most of the dangerous dog laws that have been passed are aimed at Pit Bulls (or perhaps at the gangbanger stereotypic owner). This breed is actually much more likely to be aggressive towards other dogs than to people, but they are so strong that even a brief flaring of temper can create devastating injury to anyone who gets in the way. If anyone gives the Pit Bull a bad reputation , it is the owner who doesn’t hide the fact that they want people to be afraid of their dog; they crop the ears and deck the dog with a spiked collar and keep it on a leash made of hemp rope. If anyone doubts that Pit Bull owners lead the world in irresponsible dog ownership, simply visit any animal shelter (where more than half of the dogs are usually Pit Bulls) or ask any veterinarian what breed of dog their last three Parvovirus cases were (are these dogs so tough that they don’t need vaccinations?). But fashions change, and even the Pit Bull has become a clichés. Now owners that want everyone to know how bad they are have moved on to the really dangerous mastiff breeds, such as the Neapolitan Mastiff or Cane Corso.
The particular breed that is the current Loaded Gun Dog isn’t important. Within any breed there are aggressive individuals and gentle, devoted family dogs. Genetics does make a difference; it is unlikely that Golden Retrievers or Bernese Mountain Dogs will ever appeal to the owner who wants to say “beware of my dog”. The dangerous dog phenomenon does say a lot about our society. Glorification of violence and the life of the gangsta has certainly created an image that every misfit 19-year-old can keep on a leash, and this is unlikely to change. The frightened citizen that wants to keep a dog for “protection” is another story. Loaded Gun Dogs are rarely an effective safety measure, and they are more likely to hurt someone in the family or cause a neighborhood lawsuit than they are to foil an attack. Dogs that act aggressively usually require confinement, and owners soon reprimand the dog for its constant barking and growling. The best protection is a dog which is friendly, well trained, and strongly bonded to family members. When the sweet Golden Retriever growls and raises its hackles at the approach of a suspicious stranger, the owner knows that her dog will rise to the occasion to protect the people that it loves.
Every unexpected behavior in dogs and cats is a little mystery, and the reasons pets behave as they do are often opaque. In the course of daily veterinary practice, pet owners often ask about why their dog or cat behaves in a particular way: Does this behavior mean he is sick? Is there a reason that we don’t understand? Or is he just crazy?
Recently I had two dogs that had the same issue: Both dogs refused to go out on a walk in the evening. One of the owners thought their dog might be painful when it walked (although it didn’t limp, and bounded energetically into my exam room), while the owner of the other dog simply thought the dog was “getting lazy”. I do love a good mystery, so I queried each owner about the details of their pet’s behavior. The explanation was the same in the two dogs.
Both dogs were similar, male Retriever-types 3 or 4 years old, and both were well-trained. There was nothing unexpected on their physical exams, and they seemed happy and in good health. Since we often see anxiety disorders related to unexpected triggers, we spent lots of time talking about things in the neighborhood that might have previously frightened the dog, but we came up empty. A clue to one of the cases was revealed when the owner commented that she really wanted to solve this problem, because her husband “really needed to get out of the house and get some exercise.” I raised my eyebrows; “So your husband is the one who walks the dog?” I asked. “What happens if you are the one who walks the dog?” “Oh, he bounds right out the door when I walk him, but I’m not the one who needs the exercise” she replied.
Mystery solved. In each case, the dog had no problem taking a walk. They simply didn’t want to leave the “woman of the house” alone and unprotected. This non-assertive protectiveness often develops as the dog (usually a male) matures and feels the call of duty to act as guardian to the females or children of the family pack.
I came of age in the 60’s, and any hint of sexism runs against my grain. Women have every right to occupy positions of authority, and I know that my wife and daughter are quite willing to take care of themselves. I might admit to feeling a little protective, but that is more because I want to feel useful than because the females in my family are weak and need a guardian.
But dogs are strongly tied to their gender roles. Females and their offspring are to be protected, while males are expected to take care of themselves. Many dog owners recognize this, and tell me that their dogs act differently when the “man of the house” is away on business. The dog may suddenly choose to sleep sprawled by the front door He may even be allowed to sleep on the bed in the absence of the human “alpha male”. Although these women often aren’t looking for a guardian, they recognize that there are being watched over by their canine companion.
Sometimes this “gender discrimination” takes on a darker tone. Often dogs with fear-based aggression are exclusively aggressive towards men. This leads many owners to suspect that their dog was abused by a man before it was adopted (and this is sometimes the case), but the fact that dogs consider men to be more “dominant” can trigger a defensive over-reaction, even when there has been no mistreatment.
If a dog is more confident, it may relish its role as “temporary alpha male” when a husband or boyfriend is absent for a few days. When the man of the house returns, he may find that his once-faithful dog is now unwilling to let him into his own bed. When dog bites man, the distraught wife often reports that her husband was bitten “unexpectedly, for no reason at all”. Actually, this reaction should have been expected; after all, the dog willingly stepped up to take on the role of male protector, and some dogs are reluctant to relinquish the role.
As with most animal behavior, we need to view things from the dog’s perspective in order to understand. Dogs naturally take family roles that are influenced by gender, but they can also learn to let go of their canine roles, at least a little, and adapt to our ways. But all of us guys have a right to feel like we are needed, if only in our own minds.
Fritz had a barking problem. For most of his 14 years of life, this lanky German Shepherd Dog barked at everything that crossed his senses. Pedestrians triggered Fritz’s tirades, even when they crossed the street to increase their distance from his fenced yard. Any dog that Fritz could see or hear caused a vocal outburst. Even cats and squirrels were the recipients of his vocalizations. Then one day Fritz died, and a strange thing happened.
Fritz shared his house and yard with a 10-year-old yellow Laborador Retriever named Lance, but Lance never barked, not ever. His owners doubted whether Lance was able to bark—until Fritz passed away. Within a week, this mild-mannered Lab could be heard loudly warning all passers-by to stay away from his yard, or else! It seemed that Lance had taken over Fritz’s role as vocal defender of the yard and chief of “homeland security”.
The story of Fritz and Lance is one that I have encountered frequently in my career as a veterinarian, and it brings up the question: Did Lance always have the urge to bark, but was intimidated by the older dog? Or did he simply feel that someone needed to warn away strangers, so he reluctantly took the job when Fritz retired permanently. In some cases, it is my impression that taking on the barking role has more to do with duty than desire. Although many dogs bark because it is a satisfying, enjoyable activity, there are other dogs that would probably rather leave the job to someone else if they could.
Humans and dogs have lived together for many thousands of years, and a sense of duty is probably one of the canine virtues that encouraged our relationship. Keep the sheep safe, defend against intruders, help find food animals. It is all in a day’s work. But there is a funny thing about work; even when you are doing what you love, the call of duty can still take a physical toll.
Nobody takes their job more seriously than seeing-eye dogs, and most sight assistance canines seem happy and devoted. One day I examined a seeing-eye dog that I had cared for every since he was a puppy. He was now 11 years old, but he looked several years younger than when I had seen him a year previously. When I asked his owner what had changed, he told me that the dog had passed the 10 year old “mandatory retirement age” and had given up his job leading the blind. This dog had enjoyed his role as leader and protector, but the reduction of stress now that he was “off duty” had a markedly positive effect of the dog’s health.
Whether we are evaluating the causes of stress in a dog with skin disease or trying to understand why the problem barker won’t be quiet, it is worth asking the question: Does this dog feel that he has a duty perform? If so, this should be taken into account.
In the case of barking, most dogs are probably “recreational barkers”, and they feel that barking is a privilege rather than a duty. There seems to be an inherent reward involved in hearing your own voice, and barking often gets results (the owner lets you into the house, or the people on the street eventually walk away). Treating problem barking is a complex training topic, involving interrupting the behavior, replacing it with a less objectionable behavior, and avoiding the triggers that cause the vocal outbreaks. But when dealing with dog behavior, one of the first questions to ask is “why does he do it?” For some dogs, they may feel that it is their duty.
“I think Max is losing his eyesight; now when I throw the ball, he sometimes hunts around for it in the grass as if he doesn’t see it at all. What’s wrong?” This is a common concern that I hear from owners of older dogs, but in fact these dogs usually see as well as they ever did. In order to understand this phenomenon, we need to understand that Max processes visual information differently from ourselves.
Human eyesight is adept at taking in the whole picture, painting a vivid landscape background at the same time as it tracks an object of interest moving within this background. This all-purpose style of visual processing served our evolutionary ancestors well as they searched for ripe fruit in the trees while hunting prey thru the jungle.
The dog’s ancestors were highly developed predators, and hunting animals look for movement, with little interest in the scenery. As a result, dogs have inherited a visual processing system that is fine-tuned to see motion. Any moving object “pops out” of a blurry, nondescript background. Once Max’s ball stops moving, it virtually disappears from sight, and scent takes over the search.
“But Max never had problems finding the ball before”, his owner insists. My best explanation is that the old dog has simply slowed down, and his diminished speed and attention now allow the ball to come to a stop more often before he reaches it. When he was younger, he was able to fetch his toy before it became a motionless part of his visual background.
This bias toward motion may also account for the faster “flicker rate” of canine vision, and why dogs don’t enjoy the movies. As every human cinephile knows, when still pictures are projected on a screen and changed more than 60 times per second, our brain fuses these stationary images into a moving picture. If the film slows down to 30 frames per second, however, the movie “flickers” as we start to perceive a series of still pictures with dark spaces in between.
In her fascinating book on dog senses and behavior called Inside A Dog, Debra Horowitz explains that dogs have a “flicker rate” of 70-80 frames per second, so they would not see action moving smoothly in a movie projected at 60 frames per second. Older television technology used “refresh rates” well below the dog’s flicker rate, so they would have seen Lassie in a series of jerky still pictures. Digital TVs have changed all that; along with a faster refresh rate, individual pixels change in sequence, rather than the entire picture. Dogs can now enjoy their favorite reality TV show right along with us.
Sometimes we need to be reminded that we live in a different sensory from our canine companions. We all see things a little differently.
The function of the yawn is a tantalizing mystery. The simple, experiential explanation—that we yawn because we are sleepy—fails to shed much light on why this behavior is universal in humans and many social animals, including dogs. Even more interesting is the common observation that yawning is contagious, at least among primates and dogs. So, what is it good for?
In dogs, yawning is often a sign of stress, boredom, or drowsiness, and it carries communication value. Recent studies confirm that dogs may exhibit a yawn to appease another dog that presents a potential threat, and it appears to have a calming effect on the recipient of the yawn. This has led dog behaviorists to call the yawn a “calming signal”, and some trainers believe that this signal has a calming effect on the yawning dog as well as the dog that receives the yawn. Teaching dogs to yawn on command has been used as a way to calm dogs in a stressful situation.
The most significant aspect of the canine yawn is that it suggests that the dog is not comfortable with its situation, and this gesture should alert the dog owner that their pet is stressed. If the yawn occurs after a lengthy training session, it suggests that shorter training sessions may be better tolerated. When a dog yawns during an outing in a noisy place full of bikes, cars, and skateboards, he is telling you that he is getting overwhelmed and would prefer a more peaceful location. And sometimes, the dog that yawns in the evening while lying in front of the fireplace may be indicating that it is simply tired and ready for bed.
Is there a physiologic reason to yawn? This question was the subject of a spirited exchange in the Letters to the Editor of the New England Journal of Medicine a number of years ago. Several doctors suggested that it helped us breathe more deeply to increase our body’s oxygen level or to eliminate a buildup of carbon dioxide, but blood gas analysis showed yawning did not give breathing a boost. Another idea put forth was that it loosened up the jaw muscles, readying us for sleep, but this notion was challenged logically by the fact that other muscles have at least as much need to be relaxed as the muscles of the throat. One doctor’s wife chimed in with an observation that seems to make the most sense. She reported an incident when she yawned before retiring for the night and suddenly noticed the smell of natural gas from her oven, which she had not smelled until she yawned. The motion of yawning raises the roof of the mouth, bringing a fresh sample of air into contact with the olfactory epithelium in the back of the nasal passage. This “breath of fresh air” allows the drowsy individual to check for the scent of lurking danger before settling down to sleep.
This “scent hypothesis” also suggests the reason why yawning is contagious (I am betting that the reader of this essay has already yawned several times just from the repeated use of the word). Wildlife biologists observing troops of chimpanzees or baboons in the wild have reported an evening ritual as the primates start to settle in for the night. First one member of the group will yawn, and then others will follow in rapid succession before everyone curls up to go to sleep. This epidemic of yawns essentially asks “Does anyone smell any danger before we settle down for the night?”.
If the purpose of yawning is to provide an olfactory “all’s clear” signal, why do dogs (and people) yawn in stressful situations? Another way of thinking about yawning is that it expresses a mental conflict, such as the clash between being tired and the need for alertness. Consider this human situation: A friend comes over to visit in the evening. Conversation is pleasant, but your visitor continues to talk until after your accustomed bedtime. Your body tells you that it wants to go to sleep, but the polite part of your brain tells you that you can’t very well ask your friend to leave just because you are tired. You have an irresistible urge to yawn, but you suppress it at first because you don’t want to insult your visitor. But the more you try not to yawn, the more the urge insists, until you can’t help giving in. A perceptive friend would likely understand the communication contained in the yawn, and perhaps would respond with a yawn of their own, reminding them that it really is getting late. In this way, nature often turns physiologic behaviors into social communication. Which reminds me that it is time to end this blog; I see you yawning, and I can take a hint.
