Exercising and Enhancing the Senses - Taste

A dog’s sense of taste is far less sensitive than our own. Dogs only have around 1,700 taste buds, whereas we have about 9,000. Humans can taste all five flavors: salty, sweet, sour, bitter, and umami (savory). Dogs (as far as we know) taste only salty, sweet, sour, and bitter. It’s interesting to note how much variation there is in how well and what sorts of things animals can taste. For example, pigs have a more sensitive sense of taste than we do, possessing about 14,000 taste buds. Chickens have only about 30 taste buds, while cats have around 470. During their evolution, cats lost the gene that detects sweet flavors.

Taste is an evolutionary adaptation for assessing whether  something is edible, although the definition of “edible” clearly varies between dogs and humans. If you’ve ever watched dogs eat, you may wonder whether they taste anything at all as they vacuum down snacks and meals, chomping and spraying food far and wide. Although the table or bowl manners of many dogs are appalling by human standards of etiquette, they certainly enjoy what makes it into their mouths.

Dogs show remarkable variability in their tastes for different foods. Jessica’s two dogs, Bella and Maya, are nothing alike. Bella has a wide palate and will eat carrots, peas, apples, raspberries, and nearly every other food offered to her. Maya dislikes fruits and vegetables and will carefully pick them out of Jessica’s offerings, even if they’re hidden under thick gravy. Marc’s dog Jethro was the consummate omnivore, refusing just about nothing: He ate everything he was offered or that he discovered on the floor, on a counter, or outdoors while on the prowl. One of his nicknames was Leadbelly. On the other hand, Marc’s dog Inuk was a disturbingly picky eater who would stick his nose up even when offered a patty of wet dog food laced with ketchup — something Jethro would instantaneously inhale without a snort. Variety is the spice of life. Indeed, dogs may enjoy, as we do, experiencing a variety of taste sensations. Who wants to eat the same stuff every day? That’s boring.

LET THEM EAT PASTA

Dog advice columns often decry giving dogs “people food,” but there is no scientific evidence that the foods we eat are necessarily bad for dogs — or at least, no more bad for them than they sometimes are for us. Indeed, this distinction between people food and dog food is more of a marketing gimmick than anything else. Dogs coevolved with humans in part by eating our leftovers and throwaways. Claims that foods such as bread and pasta are bad for dogs don’t have any scientific backing. Setting aside food that is unhealthy for anyone or poisonous, most of the foods we eat seem acceptable for dogs to eat (however, see the list of cautionary foods below). Further, it’s downright absurd to throw away leftover meat from our own dinners and then open a can of “chunk of beef” for a dog’s nightly meal. This not only wastes food but is probably less healthy for the dog. Like all processed foods, canned dog food is usually of inferior quality and probably not nearly as satisfying as fresh or freshly cooked steak will be.1

When it comes to diet, some people often compare dogs with their wolf ancestors. Advertisements for dog food may tout something along the lines of “Feed the wolf in your dog” or “Dogs evolved, but their instincts remain.” One of Maya’s favorite treats is called My Little Wolf (Turkey Bliss flavor). However cute as advertising, these sorts of comparisons can be fraught with error when it comes to actual feeding advice. For one, very few modern dogs exercise or engage in wolflike behavior patterns and activities, which require a highcaloric intake. In addition, dogs and wolves may no longer have identical nutritional needs. For example, researchers recently uncovered an interesting genetic difference between dogs and wolves, namely, that dogs appear to have a greater ability to digest starches. The wolf genome has only two copies of the gene alpha-amylase 2B (AMY2B), which helps with the processing of starch in the pancreas, while dogs have somewhere between four and thirty copies of this gene.2 When it comes to diet, treating dogs like wolves doesn’t make biological or nutritional sense.

The truth is, there is still much we don’t know about the ideal canine diet, despite the many claims we hear from dog food manufacturers, veterinarians, and self-proclaimed dog experts. Very few of these claims are backed by scientific research and actual evidence, so it’s best to treat this advice as mostly opinion and anecdote, some of which is clearly intended to sell this or that brand of dog food. Further, what’s most essential is to pay close attention to what your dog likes and dislikes and feed their fancy.

For instance, many veterinarians recommend sticking with the same food and never deviating, since some dogs get an upset stomach if their food is switched out. Although each dog owner needs to know their dog’s gastrointestinal patterns, many dogs can happily enjoy a variety of different foods. Don’t be afraid to experiment, and learn from your dog. At minimum, many dog food companies provide several flavors of dog food with the same basic nutritional profile, so even dogs with sensitive digestion can enjoy salmon one month and chicken the next, without much gastrointestinal drama.

Obviously, dogs don’t read labels, and they will often eat things that are not good for them or that are dangerously poisonous. It’s our responsibility to know what these foods are and to make sure that the foods our dogs eat are safe and healthy. Chocolate is a prime example, since it can be toxic to dogs in large quantities, and some dogs are sensitive even to small pieces that they may find lying around. Never leave a large dark-chocolate cake sitting on the counter if you have a counter-surfing dog! But there are less obvious trouble foods that we need to keep out of reach of our canine companions. If you are going to let your dog experiment and taste broadly — and you should — keep them away from foods and additives that can be harmful to them. These include chocolate, onions, garlic, avocados, nutmeg, grapes and raisins, macadamia nuts, caffeine, alcohol, marijuana, and xylitol, a sugar substitute that can be found in some sugar-free foods and gums. Finally, as we say, remember that unhealthy processed meats and sweets always make an unhealthy diet. A lunch of hot dogs, Ho Hos, and soda isn’t healthy for us, and certainly not for our dogs.

TASTING TO HELP SMELL: A DOG’S “SECOND NOSE”

Dogs possess what some people refer to as a “second nose,” called the vomeronasal organ (VNO) or Jacobson’s organ. This structure has sensory neurons that detect chemicals and is used to enhance an odor by adding taste. The VNO is a group of cells within the main nasal chamber, and while the tongue is not part of the VNO, it is used to move chemicals into the VNO. So, for example, when Bella tastes the urine of other dogs, she’s really getting an enhanced whiff accompanied by more information about who peed. The VNO is especially attuned to detect pheromones, chemicals that contain information important in social interactions.

Although humans send and receive chemical signals, we don’t have a functional vomeronasal organ. But many other mammals do, and we can see it in action. For example, some ungulates, such as mountain sheep, taste the urine of females to see if they’re in heat and ready to make more sheep, and when they do, they often curl their lips upward in what is called the flehmen response. Horses and cats also make this funny, lip-curling, teeth-baring face, but dogs typically do not display the complete flehmen response like other animals.3 However, dogs engage their VNOs in other ways. Sometimes a dog’s teeth will chatter after they lick urine or some other strongly scented area, and they may engage in what some call “tonguing,” where the tongue is pressed rapidly and repeatedly against the roof of the mouth to help move chemicals into the VNO and thus help analyze a scent.

Dogs often put their tongues into substances or onto places we might find objectionable or embarrassing in human culture, such as when dogs lick another dog’s pee. However, the tongue serves an important function in enhancing dogs’ sensory experiences, and this is yet another situation where we need to put aside our own cultural hang-ups about what’s “appropriate” and understand our dog’s behavior within the context of canine culture.

EATING GROSS STUFF: TASTING THE WILD

A couple of years ago, when Jessica was walking Maya in the desert around Fruita, Colorado, Maya found a series of tasty discoveries: a deer femur, a dried-up cow patty, a mystery morsel disguised as trash, and a who-knows-how-old pork rib left behind by picnickers. Jessica’s maternal instincts were in full swing, and she rushed after Maya, taking away one thing after another. Finally, Jessica’s husband, Chris, said, “Why don’t you just let Maya be a dog?”

Point well taken. One of the basic canine instincts is to search out and find food. And a dog’s definition of food is not the same as ours. It extends well beyond grocery-store kibble. Further, the concepts of edible, palatable, and nutritional are not necessarily the same. Whether or not some of the nasty things that dogs decide to put in their mouths have nutritional value, we should let our dogs be dogs and taste the world around them if they wish.

Of course, we may sometimes have to set limits for our own welfare. Marc remembers when his dog Moses, a giant malamute, joyfully feasted on cow patties and ran up to Marc to proudly share the odor along with some chunks that were spewing from his mouth. Moses was having a ball, but Marc stopped him because they soon were going to share a car ride back to Boulder, and there would be no escaping the smell.

It won’t surprise most people that veterinarians have specific terms for behaviors related to eating gross stuff. Perhaps the most distasteful to us is when dogs eat the excrement of other animals, a behavior known as coprophagia (from the Greek phagein, “to eat,” and copros, “feces”). Maya particularly likes deer and elk poop, garnished with a little prairie dog poop, but goose poop is the piece de resistance. It’s not entirely clear why dogs eat poop. Veterinarian Ian Billinghurst, in his book Give Your Dog a Bone, describes poop eating as a natural part of the dogs’ scavenger lifestyle. Dogs, he says, “receive valuable nutrients from material that we humans find totally repugnant. Things like vomit, faeces, and decaying flesh.” He goes on to say that feces may be highly valuable foods for dogs because they contain so much bacteria, serving as a kind of natural probiotic and adding extra bacteria to the gut’s microbiome.4

Some dogs also eat their own poop or the poop of other dogs. Puppies are more likely than adult dogs to eat their own poop, and they generally outgrow the habit. Further, dogs seem to prefer fresh stools.5 For the most part, eating dog poop won’t harm a dog, although worms and bacteria can be present in excrement.

Although it is a natural behavior, coprophagia can sometimes signal an underlying medical problem, such as gastrointestinal upset or inadequate absorption of nutrients by the gut. It should be discussed with a veterinarian, especially if it is a behavior that develops suddenly, if it is taken to an extreme, or if a dog clearly isn’t feeling well after a meal of poop.

Since we don’t really know why dogs eat poop, this is an area ripe for more research, but we understand why credible scientists, especially those worried about receiving tenure, might choose other areas of inquiry.

Nonfood objects also can make their way into a dog’s mouth and then be swallowed, both accidentally and on purpose. One veterinarian friend recently recounted to Jessica a long list of strange things he’d surgically removed from dogs’ stomachs, which included socks, wine corks, and a plastic Tyrannosaurus rex. Clearly, eating a foreign object can become life threatening for a dog (and expensive for an owner), since a dog can choke on the object, the intestinal tract can get blocked, or the object can tear the esophagus, intestines, or stomach.

For example, some dogs will remove the plastic squeakers from inside toys and swallow them. One morning last summer, a puppy friend of Jessica’s named Poppy was happily chewing on a squeaker toy. Poppy’s human looked over and saw that Poppy had dissected the toy and removed the squeaker. Just as her human reached out to take the squeaker away, the squeaker disappeared down Poppy’s throat. Poppy had to have the plastic squeaker surgically removed from her stomach. She now lives in a squeaker-free home.

“Depraved appetite” (also called pica) is a behavior in which a dog eats dirt, stones, wood, or other nonfood objects. Although not entirely understood by scientists, one possible explanation for pica is that dogs may have a nutritional deficiency (such as in iron levels). Pica may also have a psychological component and could be a response to stress. Humans, particularly young children, can also suffer from pica. Clearly, we shouldn’t let our dogs eat anything and everything. We always need to pay attention to what dogs put in their mouths because sometimes they don’t have good sense about what they should swallow. For example, the pork rib Maya found in Fruita was a bad idea, since cooked bones can splinter and cause damage to a dog’s stomach or intestines. Veterinarians disagree about the safety of raw bones. Although some say that raw bones are a healthy way to satisfy a dog’s desire to chew, some worry about possible damage to the teeth and about E. coli and other harmful bacteria that can be present on raw bones or in raw meat–based foods.

As responsible guardians, we have an impulse to protect our dogs from all dangers they may encounter. This is well intentioned, but we need to make sure we are being reasonable in what we ask of our dogs. Use your good judgment and stop them from eating things you know will make them sick or cause them harm, but just don’t overdo it.

ALWAYS PROVIDE FRESH WATER

Like all mammals, dogs have taste receptors for salty, sweet, bitter, and sour. As far as we know, they don’t have receptors for the so-called “fifth taste” of umami, which is often described as savory or meaty and which appears to be linked to taste receptors that respond to an amino acid called glutamate. Dogs may also be different from us in having the ability to taste water. Water is more salient to animals than we might have assumed, and the mammalian brain may possess specialized nerve cells that sense water (insects and amphibians have these nerve cells). Some researchers have even suggested that water is a sixth taste.6 Although not all scientists agree, some have argued that dogs do, indeed, have taste receptors for water. These receptors are located on the tip of the tongue, which dogs curl to lap water. This area of taste buds on the tongue appears to be extra sensitive after a dog has eaten salty or sugary food. Dog psychologist Stanley Coren suggests that the ability to taste water “evolved as a way for the body to keep internal fluids in balance after the animal has eaten things that will either result in more urine being passed, or will require more water to adequately process.”7

Can dogs also smell water? Anecdotal evidence from dog owners suggests that maybe they can, and this citizen science can help generate more formal research into the sensory world of dogs. For example, in early January 2017, Marc was sitting outside of a coffee shop in Boulder when he made friends with a handsome bloodhound who happened to be walking by. After receiving permission from Tommy’s human, Marc rubbed Tommy’s shoulders as they talked about Tommy’s lovely disposition, his beautiful long ears, and his amazing nose. Then Tommy started pulling toward a water bowl he couldn’t have possibly seen. Tommy’s human casually remarked, “He can smell water.” Marc was astounded, as he had never thought about this possibility.

While research continues into whether dogs taste or smell water, one important fact is well established: Dogs like fresh cool water better than warm stale water that’s been sitting in the bowl for days on end. This may provide a simple explanation for the seemingly universal desire of all dogs to drink from the toilet. Since toilet water has likely been refreshed more recently than the water in Fido’s bowl, it tastes better. Although unlikely to cause major problems, toilets can have residues from cleaning products and can harbor bacteria. If you live with a dog, redirect your dog’s attention to their water bowl by making sure the water is fresher and tastier than the toilet water.

All water isn’t the same to all dogs. It’s important to learn what your dog likes and dislikes. Some dogs are not very discriminating about their water, whereas others have more refined tastes and won’t drink from a “public” bowl. Maya, for example, won’t touch water that has been “polluted” by another dog, such as the water bowl at the dog park or outside the coffee shop, no matter how thirsty she is. So, when taking Maya for a hike or out on errands, Jessica must make sure to pack clean water and a bowl for Maya. On the other hand, Jerome, a dog Marc knew at a local dog park, loved “the filthiest water he could find,” according to Jerome’s human, and yet, apparently, Jerome never got ill.

While it may be obvious advice, it’s amazing how easy it is to forget the obvious in the hustle-bustle of a day. Do your dog a big favor and make sure they always have access to fresh water. Wash your dog’s water bowl every day, and refresh the water several times a day, if you can. This is a simple way to enhance your dog’s life. We know from our own experience that there’s nothing more satisfying than a fresh, cool glass of water.

Why clean the water bowl daily? First, because putting clean water into a rank bowl does not provide clean water for your dog, since the water is immediately dirtied. Second, the reason a dog’s water bowl gets dirty so quickly is because of the way dogs drink. Dogs don’t sip water like a person but stick their tongue into the water and create a little scoop by pulling the tongue backward and up. Watch a slow-motion video of dogs drinking — it will likely surprise you.8 The mechanics of how dogs lap water explains why there is so much drool and slobber and mess when they drink, and this introduces a lot of bacteria into the water. And what provides a nice, friendly environment for bacteria to grow? Why, tepid standing water.

This is why your dog will be happier if the water bowl is cleaned daily with soap and hot water and refilled regularly with cool water.

LET THE DROOL FLY

Something all dog owners know, but few of us love, is dog drool, aka slobber. In essence, drool and slobber simply refer to saliva that’s no longer in the dog’s mouth but rather is collecting on your pant leg, your cheek, or the floor under the dining room table. Saliva is perfectly normal, and so is drool. A dog’s salivary glands are constantly producing and excreting saliva into the mouth, and this production increases when dogs smell or taste something enticing.9 There’s no way to avoid that.

Like human saliva, dog saliva helps with eating and digestion, and it’s composed of water, mucus, electrolytes, and enzymes. Saliva binds food together into a kind of slippery bolus and lubricates the mouth and the esophagus so that the bolus of food can go down smoothly, without damaging the lining of the throat. Saliva helps make dry food soluble, and the enzymes in saliva break down starches, which is necessary to the digestive process. Perhaps counterintuitively, saliva also helps keep the mouth clean because it flushes away food debris.

Saliva production is related to taste and touch sensations in the mouth and on the tongue, and it is controlled by the brain, which explains why certain stimuli can increase saliva production, for example, when a very anxious dog salivates during a thunderstorm. Salivating also is a way for dogs to cool down (through evaporation of the liquid), and excessive salivating can indicate a problem with overheating.

Drooling is a reflex and not a behavior per se. Dogs can’t help it. So don’t get mad at your dog for prancing around with drool droplets hanging from their lips or for shaking their head and sending slobber flying all over the place. If you don’t mind a little drool, but don’t savor a drool shower, you might avoid certain breeds of dog, such as St. Bernards, mastiffs, bloodhounds, and Newfoundlands. Dogs of these breeds have loose upper lips, or “flews,” and this anatomic abnormality causes them to drool a lot.

Of course, there’s normal drool and there’s extra-heavy drool, which might start dripping from a dog’s jowls when watching someone chow down on delicious-smelling food. While we often laugh when dogs are drooling like Niagara Falls, it’s important to know that excessive drool, or hypersalivation, can be a sign of a serious medical problem, such as periodontal disease, nausea, anxiety, oral or dental disease, or motion sickness. Drooling can also be caused by pain or injury in the mouth that keeps the dog from swallowing. Ptyalism is the fancy word that veterinarians use to refer to excessive drooling.

Are there solutions to drool? Yes, carry around a towel or bib to wipe the excess. But don’t do anything drastic like buying “mouth diapers” or having surgery to reshape your dog’s lips. Dogs should be free to drool normally. In fact, we can celebrate our dogs’ special talents. November 16 is National Slobber Appreciation Day. Share your favorite drool pictures with other slobber lovers.

All in all, drooling is something all dogs do, and it’s a waste of energy to get aggravated by it. Know what a “normal” level of drool is for your dog, and if your dog drools excessively, make an appointment with a veterinarian. Otherwise, accept and love your dog and their drool.

THE JOYS OF WORKING FOR FOOD

Sometimes people claim that they wish they could be a dog because they’d just get to lay around, sniff, drool, play, and have food delivered to them in a bowl. It may surprise you, then, to know that a life of laziness is not actually what dogs want or need. Research on a whole range of different animals shows that they’ll choose to work for their food rather than take a “free lunch.” This seems counterintuitive, but it’s well established in the scientific literature. Studies conducted in the 1970s on pigeons, for example, found that they’ll continue to peck at a key to get a food reward, even if the same food is available for free. Researchers sometimes call this phenomenon “contrafreeloading.” Contrafreeloading behavior has been observed in many different species, including dogs, mice, rats, monkeys, and chimpanzees. The glaring exceptions within this research have been domestic cats, who seem to prefer being served by their human pet.

Anyone who’s lived with more than one dog knows there are differences in how hard dogs will work for food. Trainers will often use the phrase “food motivated” to describe this propensity. Some dogs are willing to learn tricks or do other things to get food, whereas others want to be fed for just being alive and so darn cute. Clearly, there are individual differences in the canine work ethic, and one aspect of knowing your dog and providing the best life possible is to be aware of individual attitudes toward hard work. Some dogs are motivated to work hard because they’re industrious. Others give up more easily; they are what we might call “lazy.” However, avoid labels and judgments and simply respond to your dog’s individual personality. If your dog really enjoys working for food, keep their life interesting by asking them to do some work and earn it.

Researchers have noted that there are two aspects of having to work for a reward like food. The first is called extrinsic motivation — the actual reward, the kibble or biscuit — and the second is intrinsic motivation, or the feeling of achievement individuals experience by having worked for that reward. Effort or work can be intrinsically rewarding because it can create positive feelings in animals and humans alike. The reward centers in our brains are wired to offer pleasure in exchange for hard effort. Just as animals may find work or effort rewarding, they may find lack of meaningful work or activity to be stressful or boring.

Some positive stress, or what researchers call “eustress” (such as being asked to work for food), can be enriching, but it’s important to know when good stress becomes harmful stress. Indeed, when too many demands are placed on an animal, whether these are demands for work or the demands of having nothing meaningful to do, animals can slip into psychological depression. For instance, dogs can suffer from “learned helplessness,” which was first studied in detail by Martin Seligman and his colleagues at the University of Pennsylvania. Learned helplessness refers to situations in which animals get to a point where they learn that nothing they do can get them out of a specific situation, so they give up. One barbaric set of studies involved the use of inescapable shock. After dogs and other animals were trained to do something to get away from the shock, the experiment was changed, and no matter what the animals did, they couldn’t avoid the shock. Another study put rats into a water tank with slippery sides and no means of escape. The rats would swim and swim and swim, but at some point, they would simply give up and drown.

Referred to as “behavioral despair” tests, these are one of the most common models for studying depression, even though they also are among the most inhumane and reprehensible types of research. However, what we now know about learned helplessness can be used to help us understand the stresses under which companion dogs live when they cannot remove themselves from bad situations. This can include chronic pain (for example, from arthritis); chronic boredom;10 being continually chained; being exposed to things that are scary, such as constant loud noise; and physical punishments, such as being yanked on a leash.

Animals clearly need to have a sense of control over their own environment, and working for food offers some sense of control. In early studies of animal husbandry and welfare, farm and laboratory animals who were given control over aspects of their environment — such as food, water, and light, by being able to obtain these through pushing a lever — grew up to be more self-confident, more exploratory, and less anxious. In short, they were emotionally healthier than animals forced to live under similar husbandry conditions who were given no control over their environment.11

Most dogs like to eat, and having them work for their meals or treats is a good way to challenge them and to enrich their lives. However, just remember that asking a dog to work for food is not the same thing as making a dog work for food. Some dog trainers insist that a dog should never get “free food”; for each little bite of kibble, the dog must do a trick or something “good.” If this works and the dog is clearly not overly stressed by having always to perform for food, this may be a reasonable approach. Be guided by your dog’s well-being, not a need to control them. For instance, Marc’s friend David used to ask his dog, Rusty, to spin around on his hind legs for food. Rusty clearly enjoyed doing this, but he did not have to do it for David’s attention or to get food. If David asked him to spin and Rusty said no, he got fed anyway.

Food can be a very useful training tool. But your dog’s life needs to be about more than obeying commands imposed by humans. There’s nothing wrong with giving a dog a treat between meals just to be friendly. This is what we do among ourselves, and it’s good for the dog and the human for the same reasons, since it helps to develop and maintain strong and positive social bonds.

Behavioral enrichments for bored dogs often center on food and feeding time. One way we can keep dogs entertained if we must be away from home for part of the day, or will be busy at the computer, is to get them something that takes a while to eat. Many different food puzzles are available at pet stores, and these can be great for dogs who like a challenge. They can also be very frustrating, so take the time to listen to your dog. Some ideas for homemade food challenges include popsicles made by freezing peanut butter or wet dog food in a Kong or small Tupperware or yogurt container, food-filled ice cubes, and frozen baby food. Search the internet for more ideas, and sometimes challenge your dog by hiding food and asking them to find it.

OFFER FOOD IN WAYS THAT SUIT YOUR DOG

What you feed your dog matters, but the ways in which food is offered are also important in developing and maintaining strong and enduring social bonds between you and your dog.

There’s no simple rule about how dogs should be fed, and each dog needs to be treated as a unique individual. One of the things we can do, as human caretakers of our canine friends, is to pay attention to the vehicle that’s used to give them food. It’s important to think about your dog’s shape, size, physical capabilities, and eating style in relation to the shape, size, placement, and height of the food bowl. What might work best to make eating pleasurable and easy for your dog? A few examples of frustrating situations for a dog might include a very hungry dog trying to eat kibble from a slick flat plate because the kibbles keep moving out of reach of their tongue; a basset hound who always comes away from dinner with half of the meal stuck to their ears; or a pug who must struggle to reach their nose down to the bottom of a very deep dish. For older dogs, a raised bowl can make eating more comfortable. Elevated food bowls are good for very large dogs — think about having to bend down to below your knees to eat your food — and shallow bowls are nice for puppies and short-nosed dogs.

Some dogs certainly “wolf down” their food, and some people like to brag about it. However, wild animals don’t necessarily do this except under certain conditions. For dogs who eat too quickly or gulp their food, which can make them sick, a slow feeder might be a good idea. Feeding by hand can be good for puppies because it helps build attachment and can help avoid competition for food, if older, bigger dogs are also present. Using different feeding methods can also reduce competition between older dogs who prefer different feeding styles.

HELP YOUR DOG STAY FIT AND TRIM

Freedom from overfeeding may sound totally counterintuitive, but too much food is unhealthy, and poor health is a freedom inhibitor. Being overweight can have a whole range of negative health effects for dogs. It can cause inflammation, heart disease, arthritis, ligament and muscle injuries, breathing problems, and liver disease, all of which can compromise a dog’s health just as they do ours. It can make it less enjoyable for dogs to walk, run, and play and can thus reduce the overall quality of life.

It’s estimated that more than half of all dogs in the United States and the United Kingdom are overweight.12 Veterinarians talk about the canine obesity crisis in the same dire terms that public health experts talk about the human obesity crisis. Many consider obesity to be one of the top welfare concerns for pets. It’s no coincidence that dogs and people have grown fat together: We and our dogs eat a lot of junk food, we eat more than we need, and we don’t get enough physical exercise. Overfeeding is a form of mistreatment, and it can have serious consequences. Jessica heard a story from her local shelter about a dog who was adopted and brought back three months later after having gained forty pounds. He had to become part of the foster program; he needed a temporary home where he could be given extra physical exercise and brought back to a healthy weight before being adopted by another family.

Like humans, dogs can be both overfed and undernourished at the same time. Plenty of doggy “junk food” is available, such as the Pup-Peroni, Snausages, and Pup Corn dog treats lining pet store shelves, smartly packaged to appeal to human consumers. As with humans, a little bit of junk food probably won’t shorten your dog’s lifespan, but no one should live on donuts alone.

Think about what you put in your dog’s mouth just as you would think about what you put in your child’s mouth. Consider the nutritional profile of your dog’s food, not just the price, since as a rule, you get what you pay for. A great deal of the so-called food on the market is garbage. That said, a wide range of moderately priced high-quality foods are available. Do research and talk with your veterinarian about your dog’s specific nutritional needs, so you can find a food that provides appropriate nutrition and, of course, that your dog enjoys. Many pet stores will allow you to return food products if your dog doesn’t like them, so you and your dog can experiment.

Finally, if you have a dog who is a little wide around the belly, measure his or her food and include snacks in your overall calorie calculations. “Eyeballing” a half cup of kibble is deceptively hard — try it and see how accurate or inaccurate you are. If you offer an overweight dog table scraps, feed less at mealtime or make the table scraps part of their meal. For dogs who are insatiable, splitting the allotted food for the day into several smaller meals can help keep them feeling more satisfied. For example, now that Maya is a senior citizen, she eats four small meals a day. She has a thyroid condition that makes her feel very hungry, and the time between meals seems very long to her. There is no rule about only feeding dogs once or twice a day. Just make sure to measure out the day’s food carefully so that you don’t feed more than is healthy.

Individual dogs obviously vary in what they need and how they process food. If you are feeding processed kibble or canned food, keep in mind that the feeding instructions on the back of a bag of dog food won’t necessarily be exactly right for your dog. The “amount to feed” guidelines given by dog food manufacturers are generally bloated. Their goal, after all, is to sell more food.

Food and feeding also can be emotionally complicated. For example, the food your dog eats can affect his or her mood13 and some dogs are stress eaters.14 Furthermore, for many people and dogs, food is love. Humans use food and feeding to build trust and attachment with their dog. And dogs, for their part, are very skilled at tugging at our heartstrings, looking longingly at us as though they are truly starving to death, even if they just ate half an hour ago. It can feel cruel to deprive hungry dogs of what they really want — namely, more food! But we don’t do dogs any favors by allowing them to become overweight. Because we control their diet, it is our responsibility to keep them at a healthy weight.

Finally, here are two interesting research tidbits about food and feeding. First, Labrador retrievers have a reputation for being food hogs. Apparently, there is a reason for this: Labs have a genetic mutation that makes them exceedingly hungry. 15 And second, if your dog isn’t “weight compromised,” you could add a little fat to their diet, and it might have a surprising side effect: When dogs eat more fat than protein, their sense of smell may improve.16

CHEWING IS IMPORTANT

Dogs don’t chew only to eat. Dogs like and perhaps even need to chew. Puppies may chew to relieve pain from teething, and some dogs may chew or gnaw on a bone to clean their teeth or to entertain themselves.

Unfortunately, when dogs share our homes, some of their chewing behavior may be unwelcome. We may get rightfully upset when our dog mutilates the television remote, our new shoes, or our sunglasses.

Naturally, dogs may not be able to discriminate what they should or shouldn’t chew. They may not be able to tell the difference between the stuffed dog toy bought specifically for them and the beloved stuffed teddy bear on a child’s bed. It’s best not to scold a dog for chewing on the wrong things. Simply redirect their behavior. Chewing, per se, is not “bad” behavior. It’s a totally normal and natural part of a dog’s repertoire. Just lock up the expensive shoes and put dangerous stuff out of reach. As with toddlers, adults are responsible for ensuring that dogs don’t have access to things they shouldn’t, and if a dog chews something forbidden, we should scold ourselves, not the dog.

That said, and as with other behaviors, excessive chewing can indicate a problem. For example, obsessive chewing can be a sign of mental distress. A dog may be trying to deal with boredom, anxiety, or loneliness. If dogs are left home alone for long periods or not provided with enough stimulation, it can lead to stress and depression (see “The Joys of Working for Food,” above). When this is the case, it seems patently unfair to punish dogs for trying to adapt to these stressors through chewing, barking, digging, or some other “bad” behavior. Instead of punitive responses, dogs need our help. With chewing, we can often provide safe and appropriate alternatives to our couch, such as Kongs, bully sticks, or Nylabones. We should also seek to address sources of underlying emotional distress by making sure our dogs get ample attention, exercise, and stimulation.

Just as people disagree about the ideal diet for dogs, there’s a considerable range of opinions about what makes an appropriate chew object for dogs. Many veterinarians advise against bones because they can break a dog’s teeth. Some people think bully sticks are great; others worry that they may carry E. coli. Some swear by rawhide, whereas others consider rawhide a choking risk or worry about the safety of the chemicals used to treat the rawhide. The best advice we can offer is to get educated about the options and make a well-reasoned choice based on your dog’s preferences, your budget, and what you consider a good balance between your dog’s pleasure and their safety.

by Marc Bekoff and Jessica Pierce.

Note

1. The ethics of what — or who — to feed our dogs is complicated. It is worth noting that many dog owners are “animal lovers” who, for themselves, have chosen a plant-based diet. Some of these people feel uncomfortable feeding meat to their dogs because of the suffering imposed on farm animals, but they do so anyway because they believe that dogs need meat in their diet to be healthy. Others decide to feed their dogs a vegan diet, whether homemade or one of the few commercially available vegan kibbles. Dogs are omnivores and can likely have their nutritional needs met by a vegan or vegetarian diet. But there isn’t yet much scientific research into what the ideal vegan dog diet would look like or how it would affect a dog’s long-term health; adequate data do not yet exist that speak to the question of whether vegetarian or vegan dogs have lower-quality lives or die younger.

2. M. Arendt et al., “Diet Adaptation in Dog Reflects Spread of Prehistoric Agriculture,” Heredity 117, no. 5 (November 2016): 301–6, https://www.ncbi.nlm.nih.gov/pmc/articles/pmc5061917.

3. This Slate essay describes the flehmen response and, more importantly, includes a link to a variety of images of animals making the flehmen face: Jason Bittel, “Why Do Dogs, Cats, Camels, and Llamas Make That Weird Face?” Slate, January 12, 2016, http://www.slate.com/blogs/wild_things/2016/01/12/dogs_cats_and_other_animals_flehmen_response_to_smell.html.

4. Ian Billinghurst, Give Your Dog a Bone: The Practical Commonsense Way to Feed Dogs for a Long Healthy Life (Mundaring, Western Australia: Warrigal Publishing, 1993).

5. Benjamin Hart et al., “The Paradox of Canine Conspecific Coprophagy,” Veterinary Medicine and Science (2018), doi: 10.1002/vms3.92. 6. Emily Underwood, “Scientists Discover a Sixth Sense on the Tongue — for Water,” Science, May 30, 2017, http://www.sciencemag.org/news/2017/05/scientists-discover-sixth-sense-tongue-water.

7. Stanley Coren, “How Good Is Your Dog’s Sense of Taste?” Canine Corner (blog), Psychology Today, April 19, 2011, https://www.psychologytoday.com/blog/canine-corner/201104/how-good-is-your-dogs-sense-taste.

8. For example, see Carl Engelking, “How Dogs Drink Revealed in Super Slo-Mo Video,” Discover, November 25, 2014, http://blogs.discovermagazine.com/d-brief/2014/11/25/how-dogs-drink-revealed-in-super-slo-mo-video/#.wl1e5n-nguk.

9. Many people, when they think of dogs salivating at the smell of food, call to mind the work of Russian physiologist Ivan Pavlov and his research on dogs. Pavlov distinguished between “unconditional” salivating that occurred when food was presented and salivating as a “conditional reflex” in response to a lab technician in a white coat — something that had become associated with food — even when no food was present. Unfortunately for Pavlov’s dogs, his research methods were barbaric. For the record, he never trained a dog to salivate to the sound of a ringing bell — something for which Pavlov is famous. For a quick review, see Michael Specter, “Drool: Ivan Pavlov’s Real Quest,” New Yorker, November 24, 2014, https://www.newyorker.com/magazine/2014/11/24/drool.

10. Barbara King, “Dogs and Pigs Get Bored, Too,” National Public Radio, August 10, 2017, https://www.npr.org/sections/13.7/2017/08/10/542438808/dogs-and-pigs-get-bored-too.

11. Michael W. Fox, Laboratory Animal Husbandry: Ethology, Welfare, and Experimental Variables (Albany: State University of New York Press, 1986), 117–18.

12. For UK statistics, see Alexander J. German et al., “Dangerous Trends in Pet Obesity,” Veterinary Record 182 (2018), https://veterinaryrecord.bmj.com/content/182/1/25.1. For US statistics, see the Association for Pet Obesity Prevention website, https://petobesityprevention.org.

13. Eleanor Parker, “How Your Dog’s Food Affects His Mood,” Australian Dog Lover, April 2018, http://www.australiandoglover.com/2018/04/how-your-dogs-food-affects-his-mood.html.

14. Jessica Pierce, “Is Your Dog a Stress-Eater?” All Dogs Go to Heaven (blog), Psychology Today, March 27, 2018, https://www.psychologytoday.com/us/blog/all-dogs-go-heaven/201803/is-your-dog-stress-eater.

15. Eleanor Raffan et al., “A Deletion in the Canine POMC Gene Is Associated with Weight and Appetite in Obesity-Prone Labrador Retriever Dogs,” Cell Metabolism 23 (2016): 893–900. See also Alexander Bates, “Why Are so Many Labradors Fat?” New Scientist, May 4, 2016, https://www.newscientist.com/article/2086840-why-are-so-many-labradors-fat.

16. Carly Hodes, “More Fat, Less Protein Improves Detection Dogs’ Sniffers,” Cornell Chronicle, March 21, 2013, http://news.cornell.edu/stories/2013/03/more-fat-less-protein-improves-detection-dogs-sniffers.