Unique Structure of the Dog Tongue
Unlike the relatively smooth human tongue, the dog’s tongue has a unique rough texture due to the presence of small projections called papillae. These papillae give the dog’s tongue its characteristic sandpaper-like feel that helps rasp meat from bones and lap up water.
The dog’s tongue contains intrinsic and extrinsic muscles. The intrinsic muscles alter the shape of the tongue, while the extrinsic muscles connect the tongue to surrounding structures. There are also vertical and transverse muscle bundles that provide further control and flexibility. In addition, dogs have a frenulum that anchors the tongue to the floor of the mouth.
Some key differences between human and dog tongues include:
- Dogs have around one eighth the number of taste buds compared to humans. They rely more on their sense of smell.
- Dogs lack the ability to move their tongues independently of their jaws like humans can. Their tongue motion is coupled with jaw motion.
- Dogs are unable to stick out their tongues due to the attachment at the frenulum. However, they can pant and hang their tongues out when hot.
The unique structures of the dog tongue likely evolved to allow dogs to lap liquids, graze efficiently, grip objects, regulate temperature through panting, and express emotions.
Papillae Give the Tongue a Rough Texture
A dog’s tongue contains four types of papillae that create a rough, textured surface: filiform, fungiform, circumvallate, and foliate papillae. Filiform papillae are thin, hair-like projections that cover most of the upper surface of the tongue and face backwards (1). These filiform papillae contain touch receptors and provide a rough texture that enables dogs to lap water and gather liquid effectively (2). Fungiform papillae are mushroom-shaped and mostly located on the sides of the tongue; they contain taste buds. Circumvallate papillae are larger round bumps on the back of the tongue containing many taste buds. Lastly, foliate papillae are ridges and grooves on the sides of the tongue also rich with taste buds.
While the various papillae types have some role in taste, the filiform papillae are most important for creating a rough surface. As a dog curls its tongue backwards into a spoon shape and laps, the filiform papillae act like a liquid adhesive, trapping water that gets drawn into the mouth (2). This allows dogs to gather water efficiently and lap faster than they could with a smooth tongue.
(1) Functional Anatomy and Physiology of Domestic Animals. https://books.google.com/books?id=eNooDwAAQBAJ&pg=PA546&lpg=PA546&dq=%22papillae+on+dog+tongue%22&source=bl&ots=jz0yHZzvQw&sig=ACfU3U1lYGYhTHQZ41nWE4eDAAhuGwVu4w&hl=en&sa=X&ved=2ahUKEwjDvuib_bGDAxVdfDABHZ3PCnkQ6AF6BAgJEAM
(2) The Dog Encyclopedia. https://books.google.com/books?id=q-7kDwAAQBAJ&pg=PT41&dq=dog+tongue+papillae+drink+water&hl=en&sa=X&ved=0ahUKEwj_-9X2han8AhUjlGoFHX-IBPIQ6AF6BAgGEAI#v=onepage&q=dog%20tongue%20papillae%20drink%20water&f=false
Curling Tongue Scoops Up Water
When a dog curls and unfurls their long, thin tongue into the water, they are able to scoop up a surprising amount of water. As dogs lap, they use the underside of their tongue to form a spoon shape which brings the water into their mouth.
According to a study from Time Warp – Dog Drinking, high speed video revealed that medium sized dogs can lap up water at a frequency of around 4 times per second. The unique curling action allows dogs to drink continuously without having to pause to swallow. This is an efficient way for dogs to rehydrate.
By curling the tongue on itself lengthwise, dogs are able to get the right water column height to take advantage of forces like gravity and inertia when drinking. This allows them to lap up to 7 times more efficiently than if they had flat tongues like humans.
Jowls and Cheeks Help Drinking
A dog’s loose jowls play an important role in their drinking technique by trapping water scooped up by the tongue. As a dog curls its tongue backwards, the water adheres to the rough papillae and gets transported into the oral cavity. The loose folds of skin around the jowls and cheeks help prevent the liquid from escaping. Inside the mouth, specialized muscles in the cheeks contract to move the water back towards the throat so it can be swallowed. According to studies by researchers at Virginia Tech, heavier dogs tend to have more pronounced jowls and drink water using a larger wetted surface of the tongue [1]. This shows an allometric relationship between dog size, jowl structure, and drinking strategies.
Specialized Saliva for Drinking
Dogs have adapted their saliva composition to aid in drinking. They have large salivary glands that produce copious amounts of saliva. This saliva is thinner than human saliva and contains electrolytes like sodium, potassium, and chloride.
The watery saliva allows dogs to lap water into their mouths at a speed faster than gravity can pull it down. Their tongue basically acts like a ladle scooping up the water. Without the fast-flowing, electrolyte-rich saliva, they would not be able to lap at such a rapid pace.
The electrolytes in their saliva may help replenish electrolytes lost through panting and exercise. This helps dogs stay hydrated better than just drinking plain water. It may also improve the taste of water to encourage adequate fluid intake.
Sources:
https://pets.webmd.com/dogs/features/healthy-dog-saliva
https://www.reddit.com/r/unpopularopinion/comments/9mj3zw/dog_people_are_obnoxious_and_hateful/
Drinking Strategies and Behavior
Dogs have various instincts and strategies when it comes to finding water and drinking it. Some dogs will gulp their water quickly while others take more modest sips. According to https://www.fokkerpetfood.com/en/blog/importance-of-drinking-water-in-dogs.html, a dog’s drinking behavior can provide insight into their health. For example, a dog who drinks very urgently may be dehydrated or overheated.
Dogs have an innate ability to locate water sources when needed. If outdoors, they use their powerful sense of smell to find rainwater collected in puddles, ponds, or other pools. Indoors, dogs quickly learn the location of their water bowls or drinking fountains. Some dogs prefer moving water and will drink more readily from a fountain.
Drinking too quickly comes with certain risks. Water that is gulped down can more easily go down the wrong pipe, causing choking or coughing. Drinking too fast may also lead to vomiting in some dogs. Using a slow-feed bowl or adding obstacles in the bowl can help curb fast drinking for dogs who tend to drink urgently. This encourages them to take more cautious sips.
Water Intake Needs
The amount of water a dog needs per day depends on many factors like age, size, activity level, diet, and environmental conditions. On average, the general rule is that healthy dogs should drink approximately 1 ounce of water per pound of body weight per day.
For example, a 30 pound dog needs about 30 ounces or around 4 cups of water daily. Puppies, pregnant or lactating females, dogs eating dry food, and high energy dogs may need even more water. Providing clean, fresh water at all times allows dogs to drink as needed.
Dehydration is a serious concern and can occur if a dog does not get enough water. Symptoms include lethargy, loss of appetite, dry gums, sunken eyes, and thick saliva. It’s important to monitor water intake and watch for signs of dehydration, especially on hot days or after strenuous exercise. Water bowls should be refilled frequently and electrolyte replacement fluids can help restore hydration.
Ensuring adequate daily water intake is essential for maintaining health and preventing problems like urinary tract infections, constipation, and kidney disease. Paying attention to proper hydration helps keep a dog’s body functioning properly.
Potential Drinking Problems
Dogs can develop several health conditions that affect their ability to drink properly. Kidney disease and diabetes are two common diseases that can make drinking difficult. Kidney disease leads to an increase in thirst as the kidneys struggle to concentrate urine. However, drinking excess water strains the kidneys further. Diabetic dogs often experience increased thirst as their bodies try to flush out excess sugar in the urine. Yet excessive drinking can disrupt blood sugar control.
Nose drips from allergies or dental issues like gum disease or tooth infection can make drinking uncomfortable. Facial injuries around the mouth or issues with the esophagus may also interfere with normal drinking. Dogs that have trouble drinking enough water are at risk for dehydration.
Signs of abnormal drinking or dehydration include lethargy, sunken eyes, sticky gums, weakness, vomiting, and dark yellow urine. If your dog shows any difficulties drinking or signs of dehydration, it’s important to schedule a vet visit. The vet can run tests to diagnose any underlying disease and provide treatment options to help your dog drink comfortably again.
Special bowls like those from RD.com or the LIDLOK Stainless Steel Bowl from Amazon may help make drinking easier for dogs with certain conditions. But be sure to consult your vet if your dog has ongoing problems staying hydrated.
Bowls and Fountains for Dogs
When choosing a water bowl for your dog, it’s important to select the right size. Small breeds do well with bowls that hold 1-2 cups of water. Medium dogs need bowls around 3-4 cups, while large breeds may need 6 cups or more. The material of the bowl matters too. Stainless steel, ceramic, and plastic are common options. Plastic is lightweight but can harbor bacteria. Ceramic looks nice but can break. Stainless steel is durable, easy to clean, and neutralizes odors (source).
Water fountains are a popular alternative to bowls. They provide constant circulation and filtration. The moving water encourages dogs to drink more, which is beneficial. However, fountains require cleaning and maintenance to prevent mold. They’re also prone to breakage with rough play. Consider your dog’s needs when deciding between a fountain or bowl.
Having multiple water stations around your home is ideal. Place bowls in areas your dog frequents like the kitchen, bedroom, and yard. Outdoor bowls should be weighted or secured to prevent tipping. Refresh water frequently throughout the day to ensure it’s clean and appealing (source).
Fun Facts About Dog Drinking
Some dogs can lap up water incredibly fast. The Guinness World Record for the fastest dog to lap up water is held by a greyhound named Trouble who lapped up one liter of water in just 7.65 seconds in 2016 (1). That’s the equivalent of around 5 cups of water!
There’s a myth that letting dogs drink too much water immediately after eating can cause bloating. However, there’s no scientific evidence to support this. In fact, it’s healthy for dogs to drink when they’re thirsty, even right after a meal. Moderation is always key though (2).
Some breeds like the Labrador Retriever have a scooping tongue that helps them gulp up water more efficiently. Their tongues actually curl backwards, creating a spoon shape to contain more water in each lap. Dalmatians also have this ability due to their history as coach dogs who needed to drink on the go (3).