The Real Truth about Probiotics for Dogs

Just like humans, the majority of a dog’s immune system resides in his gut. The gut is the largest immune organ in the body and contains approximately 70% of all immune cells. So keeping your dog’s digestive system running optimally is essential to making sure that he stays healthy, active, and lives a full and healthy life.
One way to potentially improve your dog’s digestive health is to offer him a daily probiotic supplement. There have been extensive studies on the benefits of probiotics in humans, however, veterinary research is just starting to really dive into how supplementing your pup with a variety of good bacteria can aid in keeping him healthy.



What are Probiotics for Dogs?


The World Health Organization (WHO) defines probiotics as “live microorganisms, which when administered in adequate amounts, confer a health benefit on the host.” According to American Kennel Club (AKC) veterinary expert, Jerry Klein, DVM, probiotics (bacteria or yeast) can potentially provide an array of health benefits to dogs.

 “They are believed to help treat and/or prevent a variety of illnesses and diseases, especially those related to the gastrointestinal system,” he explains. They inhibit the growth and activity of harmful bacteria, such as E. coli, Salmonella, and Clostridium perfringens, as well as provide other advantages to the intestines.


Brennen McKenzie, VMD, who practices at Adobe Animal Hospital in Los Altos, California, has studied the use of probiotics in canines extensively and believes that there are definitely some benefits to dogs taking them. “In theory, if probiotics can pass through the stomach and colonize the intestines, they can have a variety of desired effects, such as preventing or treating diarrhea or improving other intestinal conditions, such as inflammatory bowel disease,” he states.


Benefits of Probiotics for Dogs


In a peer-reviewed journal, Marcella D. Ridgway, VMD, MS, DACVIM notes that there is growing evidence that supports the use of probiotics for dogs. She states that giving your dog healthy bacteria may positively impact chronic GI abnormalities, obesity, liver disease, and mood and behavior disorders. A daily probiotic supplement may also provide some ancillary benefits for dogs such as better skin and coat appearance, a reduction in gas, improved breath, a reduction of allergy symptoms, a reduction in yeast-associated disorders, and help in regulating bowel function.


Types of Probiotics for Dogs


Probiotics for dogs come in a variety of shapes and sizes. “Some are marketed just for dogs, some for a range of animals, and some for humans (that are subsequently used in dogs),” says J. Scott Weese, DVM at the Department of Pathobiology at the Ontario Veterinary College. “These can come as pills, powders, pastes, or solutions.”
Each probiotic supplement contains one or more types of bacteria and/or yeast that can carry out a variety of different functions. For instance, certain strains, such as Bifidobacterium, are known to be helpful in slowing down the duration of diarrhea in dogs and for their overall immune boosting properties. Other types, like Lactobacillus, have shown benefits in helping dogs to increase the absorption of nutrients and to optimize their digestive systems.



What to Look for in a Dog Probiotic


“There is no one probiotic supplement that is best for every dog and every health condition,” says Dr. Jennifer Coates, Veterinary Advisor for petMD.  Most veterinarians carry a number of different products from trusted manufacturers and will try several before concluding that probiotics aren’t going to be helpful in a particular case. Dr. Coates reports that the following probiotic strains have some scientific evidence to support their safety and efficacy in dogs:


- Enterococcus faecium
- Lactobacillus acidophilus
- Lactobacillus casei
- Lactobacillus plantarum
- Bifidobacterium bifidum
- Bifidobacterium animalis
- VSL #3


Can I Give My #Dog Probiotics Meant for Humans?


While there are no known studies that prove that human probiotic supplements can harm a dog, veterinarians that study the subject recommend that pet owners opt for a probiotic that is specially made for dogs and contains the specific strains that a dog’s gut needs. “There are significant differences in the biology of dogs and humans, including differences in the acidity of stomach fluids, digestive enzymes, and other features of the gastrointestinal tract,” says McKenzie. “Because probiotics for humans have not been designed or tested to accommodate the biology of dogs, it is impossible to know if these will be safe or effective in our canine companions. It is safer to use products designed and tested for dogs.”


How to Give a Dog a #Probiotic


Canine probiotic supplements are administered orally and can be included in a dog’s food or wrapped in a treat. When administering a probiotic to a dog, it’s very important that you follow the instructions on the product label. “Each product has its own instructions which should be followed consistently,” says McKenzie. “Improperly formulated or administered probiotics can easily be destroyed in the stomach and not reach the intestines where they are intended to perform their function.”


Risks and Considerations of Probiotics for Dogs


There are not many known side effects to administering probiotics to your dog. “Probiotics are generally regarded as safe, but rare things can happen,” says Weese. “The risks to the average dog are exceptionally low and probably are only potentially relevant in very young puppies and maybe animals with highly compromised immune systems.” He stresses, however, that there are notable problems with the formulation of commercial probiotics for pets. “A few studies have shown that most commercial veterinary probiotics do not contain what they claim to contain—both the species that are present and the numbers of viable organisms,” he explains. For this reason, it is important to do your research and talk to your veterinarian to make sure that you are giving your dog a probiotic supplement from a trusted and reputable brand.

As always, talk to your veterinarian before deciding to give your dog any sort of supplement or treatment intended to help resolve health problems. “This is particularly true for probiotics, as specific manufacturing standards and appropriate dosage levels have not been established,” warns Klein. “Your veterinarian will have the best perspective on whether or not your dog may benefit from probiotics, what the best brand may be for your dog, and the appropriate dosage.”

Adopt a Pet

Every dog or cat not purchased from a pet store or backyard breeder improves the pet overpopulation problem created by irresponsibility and greed.
Adopting a dog or cat from a no-kill shelter can free up space for older or special needs pets that may not find new homes before the end of their natural lives.

Adopt a Pet

There are plenty of animals to choose from at most shelters. They come in every age, shape, size, coat color and breed mix, and you can find purebreds at shelters as well. In fact, many breeds have their own rescue organizations, so if you're looking for a purebred, make sure to check both your local shelter and breed rescue organization.


Compared to the cost of purchasing a pet, adopting one from an animal shelter is relatively inexpensive. And if you get a slightly older dog or cat, there's a good chance he is already fully vaccinated and neutered.

Adopting an older pet allows you to skip over the time consuming, often frustrating puppy or kitten stage of development.

Adopting a mature dog or cat also takes the guesswork out of determining what your pet will look like as an adult – what size she'll grow to, the thickness and color of her coat and her basic temperament, for example.
Depending on his background, your older pet may already be housebroken or litter box trained and know basic obedience commands like come, sit, stay and down.

Most shelters and rescue organizations do assessments on every new pet taken in, to determine things like temperament, whether the pet has any aversion to other pets or people, whether he is housebroken, has had obedience training, etc. Many of these organizations also have resources to help pets with lack of training or behavioral issues. So when you adopt a pet from one of these organizations, you have a pretty good idea what to expect from your new dog or cat when you bring him home.


Many shelters and rescues also provide lots of new owner support in the form of materials about training, common behavior problems, nutrition, basic grooming and general care. In some cases there are even free hotlines you can call for questions on behavior, training and other concerns.
If you have kids, and especially if the new pet will belong to a child, adopting a shelter animal can open a young person's eyes to the plight of homeless pets. It can also help him learn compassion and responsibility, as well as how wonderful it feels to provide a forever home to a pet that might otherwise live life in a cage, or be euthanized.

An older adoptive pet can be the perfect companion for an older person. Many middle-aged and senior dogs and cats require less physical exertion and attention than younger animals.

An adopted pet can enrich your life in ways both big and small. The unconditional love and loyalty of a dog or cat can lift depression, ease loneliness, lower blood pressure, and give you a reason to get up in the morning. A kitty asleep in your lap feels warm and comforting. A dog that loves to walk or run outdoors can be just the incentive you need to start exercising regularly.

There are countless benefits to pet ownership, and when you know you saved your furry companion from an unpleasant fate, it makes the bond you share that much more meaningful.

Why Is My Dog's Fur Changing Color & Thinning?

A sleek and shiny coat is one sign of a healthy dog. Changes in your dog's coat, either in color or in thickness, can signal that something is not quite right. Many things can cause these changes, from normal aging to more serious conditions that require attention. Paying attention to your dog's coat over time can help you gauge the quality of his health and be attentive to his needs.





Aging

Much like people, dogs tend to lose pigmentation in their fur as they get older. Generally, white or graying fur on an elderly or middle-aged dog is most noticeable around the muzzle, although white or gray hairs can spring up throughout the dog's entire coat. Thinning fur is also common among aging dogs. These are usually accompanied by other signs of aging, such as a gradual loss of hearing or vision, or the dog having difficulty moving as well as it used to. If your dog is advanced in years but otherwise healthy, then graying or thinning hair is most likely nothing to worry about.



Medical Conditions


There are a number of medical conditions that can cause hair loss or changes in pigmentation in dogs. These range from skin conditions, such as mange or flea dermatitis, to hormonal deficiencies such as hypothyroidism or Cushing's disease, to more serious illnesses such as cancer. If fur loss or discoloration seems more extreme than simple aging, or is accompanied by other symptoms such as a rash, unexplained lumps on the body, or changes in appetite or stool consistency, or anything else about your dog that strikes you as not quite right, you should have him checked out by a veterinarian as soon as possible.


Stress


Dogs are very sensitive creatures who don't react well to stress. Too much stress can cause dogs to suddenly lose their fur. After removing the source of the stress from the dog's environment, or removing the dog from the stressful situation, its fur will most likely grow back in time.


Poor Nutrition

Pattern baldness in a dog, focused mainly around the ears, can be a sign of malnutrition. If you notice this type of hair loss, check your dog's diet to make sure he is getting the right balance of nutrients in the correct amounts for his size and weight. You may need to consider adding a nutritional supplement to his diet.

Senior Dogs

Senior dogs have different care requirements than those of a younger dog. This fact probably doesn’t come as a surprise to anyone. But how do you know when your dog is considered to be a senior?
It really depends on the individual dog. In general, giant breed dogs age faster than smaller breed dogs. A Great Dane is considered to be senior by roughly 5-6 years old whereas a Chihuahua would likely only be middle-aged then, and probably not considered a senior until 10-11 years. Large breed dogs fall somewhere in between. A Golden Retriever might be considered senior by 8-10 years of age. Genetics, nutrition, environment; all of these play a role in how fast your dog ages.

What are some of the things to expect as your dog ages? Your dog may develop arthritis or other degenerative diseases that cause him to slow down. He may not be able to walk as far or play as long. He may tire more easily. He may have difficulty getting up or finding a comfortable position to sleep in. He may become reluctant to go up and down stairs or have difficulty getting into and out of the car.


Without proper care, dental disease can pose a problem, particularly for older pets. You may be surprised to learn that veterinarians find evidence of dental disease in many pets as early as 2-3 years of age. If nothing is done to care for your dog’s mouth, by the time your dog is a senior, he may even have lost some teeth. Dental disease can be painful, causing your dog to avoid or have difficulty eating his meals. This may result in weight loss and an unkempt hair coat.
Dental disease is certainly not the only disease that can lead to weight loss. Senior dogs frequently suffer from kidney disease, liver disease, heart disease and other conditions that may result in weight loss.
On the other hand, some senior dogs may have the opposite problem. Some dogs will become less active with age, essentially becoming couch potatoes, and will gain weight as a result. Obesity in a major health issue in dogs of all ages and senior dogs are no different.

What can you do to help your senior dog? Here are some tips:

Schedule regular visits with your veterinarian. Your dog needs to be examined at least yearly if it appears healthy, as many diseases are hidden and not apparent. Remember it is much cheaper to prevent disease than it is to treat it!

Ask for a body condition evaluation during each vet visit. Body condition is crucial to determining whether your senior dog is overweight, underweight, or at an ideal body weight. In fact, you should also ask your veterinarian to show you how to evaluate your dog's body condition at home.

Feed your older dog a high quality diet. Also, learn to read the dog food label and choose a diet that is appropriate for your dog’s age and lifestyle.

Use food to keep your senior dog at his ideal body weight. Overweight dogs have a higher incidence of diseases such as diabetes, heart disease, skin disease, even cancer. Your veterinarian can help you choose an appropriate diet for your dog, especially since overweight dogs must be fed carefully to ensure that all nutrient needs are met while still allowing for weight loss. For instance, specialized diets that are lower in calories as well as those that are high L-carnitine are available for obese or overweight dogs. A diet with a carefully chosen carbohydrate or carbohydrate blend can also help keep your overweight dog feeling satiated.

Consider fortifying your senior dog’s diet with fatty acids such as DHA and EPA. They have been shown to be useful for dogs with mobility issues due to arthritis or other joint diseases. Supplements such as glucosamine and chondroitin are also beneficial for senior dogs.

Consider a special diet if your older dog has heart or kidney disease. For example, diets lower in sodium are sometimes advocated for dogs with heart disease, while diets which help control phosphorus, calcium and other electrolyte levels are given to dogs with kidney disease. Your veterinarian can help you choose the best food for your dog based on your dog’s individual situation.

Take care of your dog’s mouth. Brushing your dog’s teeth may seem like a silly idea but it can help keep your dog’s mouth healthy. If you cannot brush, consider dental treats and toys that help keep the teeth clean.
Exercise your senior dog. It can help keep your older dog lean and maintain healthy joints and muscles. However, tailor your dog’s exercise needs to his individual requirements. For a large breed dog, walking around the block is probably just getting started but for a tiny Chihuahua, a brisk walk around the block may be a long trek. If your senior is not used to exercise, start slow and gradually increase the intensity — and only after you’ve consulted a veterinarian. Also, be careful with short-nosed (brachycephalic) dogs on hot days.

Provide plenty of toys to keep your senior dog occupied. Food puzzles, for example, are not only useful for entertainment but for weight loss purposes as well.

Provide your older dog with special accommodations too. For instance, dogs with arthritis might benefit from soft bedding in the form of a special dog bed or towels/blankets on which to sleep. Ramps can be used to make stairs easier to navigate if they cannot be avoided. Even providing carpeting or rugs over hard-surface flooring can help your arthritic dog gain his footing and make it easier for him to get around.

What are Probiotics

Probiotics are live bacteria and yeasts that are good for you, especially your digestive system. We usually think of these as germs that cause diseases. But your body is full of bacteria, both good and bad. Probiotics are often called "good" or "helpful" bacteria because they help keep your gut healthy.

Types of Probiotics

Many types of bacteria are classified as probiotics. They all have different benefits, but most come from two groups. Ask your doctor about which might best help you.

Lactobacillus. This may be the most common probiotic. It's the one you'll find in yogurt and other fermented foods. Different strains can help with diarrhea and may help people who can't digest lactose, the sugar in milk.

Bifidobacterium. You can find it in some dairy products. It may help ease the symptoms of irritable bowel syndrome (IBS) and some other conditions.

Saccharomyces boulardii is a yeast found in probiotics. It appears to help fight diarrhea and other digestive problems.

What Do They Do?

Among other things, probiotics help send food through your gut by affecting nerves that control gut movement. Researchers are still trying to figure out which are best for certain health problems. Some common conditions they treat are:


Irritable bowel syndrome
Inflammatory bowel disease (IBD)
Infectious diarrhea (caused by viruses, bacteria, or parasites)
Diarrhea caused by antibiotics

There is also some research that shows they're useful for problems in other parts of your body. For example, some people say they have helped with:


Skin conditions, like eczema
Urinary and vaginal health
Preventing allergies and colds
Oral health

Dogs | German Shepherd Dog (Alsatian Wolf)

The German Shepherd Dog, also known as the Alsatian in Great Britain and parts of Europe, is among the top 10 most popular dog breeds in the U.S., and probably one of the world's most recognized breeds.
He owes part of his renown to a small puppy who was plucked from a bullet- and bomb-riddled breeding kennel in France during World War I by Corporal Lee Duncan. At the end of the war Duncan brought the puppy back to his hometown of Los Angeles, trained him, and turned him into one of the most famous dogs in show biz: Rin Tin Tin. Rin Tin Tin went on to appear in dozens of movies and, at the height of his stardom, got 10,000 fan letters a week.The German Shepherd has held many jobs other than movie star: leading the blind, chasing down criminals, sniffing out illegal substances, serving in the military, visiting the sick, and herding stock are just some of the jobs held by this versatile breed.

The dog has even taken on the role of national hero. German Shepherds were the search and rescue dogs crawling through the ruins of the World Trade Center after the 9/11 terrorist attacks, looking for survivors and comforting rescue workers and families.

The German Shepherd may embody some of the best traits of dogs, but he's not for everyone. Originally bred to herd flocks all day, this is a high-energy dog who needs a lot of activity and exercise. Without it, he's likely to express his boredom and frustration in ways you don't like, such as barking and chewing.

The breed also has an aloof and sometimes suspicious nature — great for a watchdog but not the sort of family dog who'll make guests feel welcome. But if you expose a German Shepherd to many different situations and people starting in puppyhood, he can learn to take new people and circumstances in stride.

If you're buying a puppy, you'll get a slightly different kind of German Shepherd depending on whether you choose an American versus a German breeder. In general, American breeders are often aiming to create dog show champions, and they breed puppies more for that distinctive German Shepherd look than for those distinctive German Shepherd talents.

Fans say that American-bred German Shepherds are calmer than their German counterparts, but critics say these dogs have lost some of their talents for working traditional German Shepherd jobs, and are more prone to behavior problems such as separation anxiety.

German breeders, on the other hand, breed German Shepherds for their working abilities as well as to fit the breed's traditional look. Before a German Shepherd is bred in Germany, he has to pass numerous tests to prove he measures up to the physical and mental benchmarks the breed is known for. German Shepherd Dogs from Germany tend to have a more energetic and driven personality.

The German Shepherd is a relatively new breed, dating back to 1899, and he owes his existence to one man: Captain Max von Stephanitz, a career captain in the German cavalry with a goal of creating a German breed that would be unmatched as a herding dog.

Centuries before von Stephanitz came along, farmers in Germany, as in the rest of Europe, relied on dogs to drive and protect their herds. Some dogs were legendary for their skill, and sheepherders would travel days to breed their female dogs to a notable sire. However, as von Stephanitz noted, no one had developed the herding dogs of the region into a distinct breed.
In 1898, von Stephanitz retired from military life and began his second career, and what would prove to be his passion: experimenting with dog breeding to create a superior German herding dog. Stephanitz studied the breeding techniques of the British, noted for their exceptional herding dogs, and traveled throughout Germany, attending dog shows and observing German-type herding dogs.

Von Stephanitz saw many fine herding dogs, dogs who were athletic, or intelligent, or capable. What he didn't see was a dog who embodied all those traits.
One day, in 1899, von Stephanitz was visiting a dog show when a wolfish-looking dog caught his eye. He immediately bought the dog, named Hektor Linksrhein. Later renamed Horand v Grafeth, the dog's powerful physique and intelligence so impressed von Stephanitz that he formed a society — the Verein fur deutsche Schaferhunde — to found a breed out of Horand's descendents.
Although he had intended for his breed to work as herding dogs, as Germany became more and more industrialized, von Stephanitz saw the need for such dogs fading. He was determined that his breed would continue as a working dog, and he decided that the dog's future was in police work and military service.

Making good use of his military connections, von Stephanitz convinced the German government to use the breed. During World War I the German Shepherd served as a Red Cross dog, messenger, rescuer, guard, supply carrier, and sentry.

Although German Shepherds made their way to the United States before the war, it wasn't until the war that the breed became popular in the U.S. Allied servicemen noted the dog's bravery and intelligence, and a number of dogs went home with these soldiers.

One such dog was a five-day-old puppy plucked from a bomb-riddled kennel in France by an American corporal from Los Angeles. The corporal took the puppy home, trained him, and turned him into one of Hollywood's most recognizable four-legged stars: Rin Tin Tin, who appeared in 26 movies and helped popularize the breed in America.

Although the Allies were impressed by the German dogs, they weren't so happy with the dog's German roots. During wartime all things German were stigmatized, and in 1917, the American Kennel Club (AKC) changed the breed's name to the Shepherd Dog.

In England, the dog was renamed the Alsatian Wolf Dog, after the German-French border area of Alsace-Lorraine. The AKC went back to using the original name of German Shepherd Dog in 1931; it took until 1977 for the British Kennel Club to do the same.

Von Stephanitz stayed closely involved with the development of the breed, and as early as 1922, he became alarmed by some of the traits that were turning up in the dogs, such as poor temperament and a tendency to tooth decay. He developed a system of tight quality control: Before any individual German Shepherd was bred, he needed to pass numerous tests of his intelligence, temperament, athleticism, and good health.

American breeding of German Shepherds, on the other hand, wasn't nearly so regulated. In the United States, the dogs were bred to win dog shows, and breeders put more emphasis on looks and on the dogs' gait, or way of moving.

After World War II, American- and German-bred German Shepherds began to diverge dramatically. At one point, the U.S. police departments and military began importing German Shepherd working dogs, because homegrown German Shepherds were failing performance tests and plagued by genetic health conditions.
In the past few decades, some American breeders have begun to put the emphasis back on the breed's abilities rather than just appearance, importing working dogs from Germany to add to their breeding program. It's now possible to buy American-bred German Shepherds that live up to the breed's reputation as a capable working dog.

The German Shepherd personality is aloof but not usually aggressive. He's a reserved dog; he doesn't make friends immediately, but once he does, he's extremely loyal. With his family he's easy-going and approachable, but when threatened he can be strong and protective, making him an excellent watchdog.

This highly intelligent and trainable breed thrives on having a job to do — any job. The German Shepherd can be trained to do almost anything, from alerting a deaf person to a doorbell ring to sniffing out an avalanche victim.

One thing he's not good at is being alone for long periods of time. Without the companionship he needs — as well as exercise and the chance to put his intelligence to work — he becomes bored and frustrated. A German Shepherd who's under-exercised and ignored by his family is likely to express his pent-up energy in ways you don't like, such as barking and chewing.

Like every dog, the German Shepherd needs early socialization — exposure to many different people, sights, sounds, and experiences — when they're young. Socialization helps ensure that your German Shepherd puppy grows up to be a well-rounded dog.

If he's well trained and has had plenty of exposure to kids, especially as a puppy, a German Shepherd is a great companion for children. In fact, some say he's a cross between a babysitter and a cop, both gentle with, and protective of, the children in his family.

This is a big dog, though, capable of mistakenly bumping a toddler or small child. True to his reserved nature, he's not tail-wagging friendly with kids he doesn't know, but he's generally trustworthy.

The German Shepherd can also live peacefully with other dogs and pets, as long as he was taught to do so from puppyhood. Introducing an adult German Shepherd to a household with other pets can be more difficult if the dog isn't used to getting along with other dogs or cats. You may need to hire a professional trainer to help, or get advice from the rescue organization if that's where you acquired the adult German Shepherd.

Dog | Akita Inu

The Akita is a large and powerful dog breed with a noble and intimidating presence. He was originally used for guarding royalty and nobility in feudal Japan. The Akita also tracked and hunted wild boar, black bear, and sometimes deer. He is a fearless and loyal guardian of his family. The Akita does not back down from challenges and does not frighten easily. Yet he is also an affectionate, respectful, and amusing dog when properly trained and socialized.
There are two types of Akitas, the original Japanese Akita breed and now a separate designation for American standard Akitas. The weights and sizes are different and the American standard allows a black mask, whereas the original Japanese breed standard does not allow for a black mask. According to the FCI, in Japan and in many other countries around the world the American Akita is considered a separate breed from the Akita Inu (Japanese Akita). In the United States and Canada, both the American Akita and the Akita Inu are considered a single breed with differences in type rather than two separate breeds.


The Akita is docile, intelligent, courageous and fearless. Careful and very affectionate with its family. Sometimes spontaneous, it needs a firm, confident, consistent pack leader. Without it, the dog will be very willful and may become very aggressive to other dogs and animals. It needs firm training as a puppy. The objective in training this dog is to achieve a pack leader status. It is a natural instinct for a dog to have an order in its pack. When we humans live with dogs, we become their pack. The entire pack cooperates under a single leader. Lines are clearly defined. You and all other humans MUST be higher up in the order than the dog. That is the only way your relationship can be a success. If the dog is allowed to believe he is the leader over the humans he may become very food-possessive as he tells the humans to wait their turn. He eats first. Considered a first-class guard dog in Japan, Japanese mothers would often leave their children in the family Akita's care. They are extremely loyal and thrive on firm leadership from their handlers. They should definitely be supervised with other household pets and children. Although the breed may tolerate and be good with children from his own family, if you do not teach this dog he is below all humans in the pack order he may not accept other children and if teased, Akitas may bite. Children must be taught to display leadership qualities and at the same time respect the dog. With the right type of owner, the proper amount of daily mental and physical exercise and firm training, they can make a fine pet. Obedience training requires patience, as these dogs tend to get bored quickly. The Akita needs to be with its family. It vocalizes with many interesting sounds, but it is not an excessive barker.

Dogs and humans respond to emotionally competent stimuli by producing different facial actions

The commonality of facial expressions of emotion has been studied in different species since Darwin, with most of the research focusing on closely related primate species. However, it is unclear to what extent there exists common facial expression in species more phylogenetically distant, but sharing a need for common interspecific emotional understanding. Here we used the objective, anatomically-based tools, FACS and DogFACS (Facial Action Coding Systems), to quantify and compare human and domestic dog facial expressions in response to emotionally-competent stimuli associated with different categories of emotional arousal. We sought to answer two questions: Firstly, do dogs display specific discriminatory facial movements in response to different categories of emotional stimuli? Secondly, do dogs display similar facial movements to humans when reacting in emotionally comparable contexts? We found that dogs displayed distinctive facial actions depending on the category of stimuli. However, dogs produced different facial movements to humans in comparable states of emotional arousal. These results refute the commonality of emotional expression across mammals, since dogs do not display human-like facial expressions. Given the unique interspecific relationship between dogs and humans, two highly social but evolutionarily distant species sharing a common environment, these findings give new insight into the origin of emotion expression.


The common origin of emotions has long been a subject of scientific interest with different emotional responses producing a diverse range of communicative elements, especially through the face. Facial expressions are also correlates of internal state in both humans and other animals and so may be used, in part, to infer emotion alongside other component processes, such as physiological activation and behavioural tendencies.
Many studies use an holistic approach (i.e. categorizing the whole face as angry, happy, etc.) to classify the target facial expressions, which reflects the way the human brain processes faces, but can be problematic when examining the underlying mechanism of emotion perception across species. For instance, there is a diverse range of smiling faces with different visual characteristics and different emotional meanings in humans. As a classic example, the Duchenne smile (felt, true enjoyment) differs by one muscle contraction from the non-Duchenne smile (unfelt, usually produced in formal greetings). Moreover, during laughter and depending on the context, a blend of both Duchenne and non-Duchenne smiles is often observed. Hence, simply classifying a facial expression as “happy” is too simplistic and less meaningful for cross-species comparison. Furthermore, the same ‘holistic’ facial morphological configuration could have different functional meanings (i.e. result in distinctly different behavioural consequences) depending on the species. For example, the Play Face (PF) and the Full Play Face (FPF) are variants of the same facial expression, where the former presents an open mouth with lower teeth exposed, and the latter incorporates visible upper teeth. Both the PF and the FPF represent different degrees of playful expression in great apes (humans included). Conversely, in crested macaques, mandrills and geladas, the FPF is not just a more intense version of the PF, but instead is derived from convergence between the PF and the silent-bared teeth display (SBT), a facial expression observed in affiliative settings such as grooming. Additionally, the SBT indicates submission and appeasement in Barbary macaques, signals affinity and benign intentions in humans, and, in chimpanzees, is present in a range of situations from response to aggression to affinity contexts.
As an alternative to an holistic descriptive approach, the decomposition and objective description of distinct anatomical regions of facial features, such as occurs with the Facial Action Coding System (FACS), has been the golden standard to study human facial expressions of emotion across individuals of different races and cultures for several decades. Each of the discrete facial movements identified (Action Units, AUs) is the result of an independent facial muscle contraction that can produce several changes in appearance to the face, which in turn are used to identify which AUs are activated. Thus, FACS codes facial movements from a purely anatomical basis, avoiding circular reasoning or a priori assumptions of emotion meaning. Recently, FACS has been adapted to several non-human species, such as chimpanzees and orangutans, following the original methodology and has proven to be a successful tool for objectively investigating and comparing facial expressions of closely related species. For example, chimpanzees and humans share an identical facial muscle plan (differing by only one muscle), but chimpanzees display both homologous (e.g. play face and human laugh) and species-specific expressions (e.g. pant-hoot).
While the human prototypical facial expressions of emotion are well established, little is known about the quantitative and empirical nature of the emotional facial displays of the domestic dog, an evolutionarily remote, but socially complex species which often shares the human social environment and frequently engages in interspecific communication with an emotional content . To date, functional facial expressions in dogs have been largely discussed holistically in relation to their approach-avoidance value, for example, the “threat gape” in fight-flight situations, and the PF or the Relaxed Open Mouth (ROM) as a social communicative signal for play solicitation and within play bouts. With the development of the FACS for the domestic dog, it becomes possible to apply a bottom-up technique to investigate the composition and meaning of dogs’ facial expressions and, more importantly, to establish possible analogies with humans, with whom they socially interact.
Dogs and humans, like other mammals, have a homologous facial anatomy plan even though they belong to phylogenetically distant groups. Additionally, both species share a common mammalian neuroanatomy for the basic emotions such as fear and happiness, typically live in a common social and physical environment, are very facially expressive , and respond to the same or similar conspecific and heterospecific social cues. Consequently, the facial cues and expression of emotion in home-dwelling pet dogs provide a unique comparative model for the study of phylogenetic inertia (i.e. absence of expected change and/or adaptation to an optimal state given specific selection pressures in the current environment) versus evolutionary divergence (i.e. a set of changes brought about by selection pressures from a common ancestor resulting in homologies) versus evolutionary convergence (i.e. a set of changes from selection pressures acting in independent lineages to create similarity in the resulting analogies).

Here, we investigated the mechanistic basis of facial expressions in humans and dogs, by objectively measuring their video recorded facial actions during immediate reactions to emotionally-competent stimuli. The FACS and the DogFACS were applied in a range of contexts associated with four categories of emotional responses: a) happiness, b) positive anticipation, c) fear, and d) frustration . Instead of selecting the basic emotions that are known to produce universal facial signals in humans, we focused on emotions that are defined by evolutionary and biologically consistent criteria: 

1) essential for solving adaptive problems in mammals (e.g. fear of a threat prompts flight increasing survival), 

2) arise from corresponding physiological markers and 

3) correlate with specific neuroanatomical regions . This approach reduces anthropomorphic and anthropocentric bias in the selection and comparison of emotions, i.e. instead of trying to identify stereotypically human emotions in dogs, we focused on examining shared underlying mammalian homologies. Furthermore, for each category of emotion (e.g. fear), we used a range of contexts to generate the emotional response (thunderstorms, specifically avoided objects, etc.). This increased the likelihood of identifying the general facial responses to the emotional category of stimulus (e.g. general facial actions of fear), instead of behavioural motivations (e.g. facial actions displayed for thunderstorms, but not in other fear contexts). We only analysed spontaneous emotional reactions because posed responses could differ from spontaneous ones in duration, intensity, symmetry and form.