Introduction
There is an ongoing debate about whether dogs and cats should be classified as carnivores or omnivores. While these common household pets exhibit some traits of both, most experts consider them to be obligate carnivores. This means their natural diet in the wild consists primarily of meat.
Carnivores are animals whose diets consist of at least 70% meat or animal-derived nutrients. They have sharp teeth and short digestive tracts designed to consume and digest animal flesh efficiently. True carnivores cannot properly digest plant matter and must have a high concentration of protein and fat in their diets from sources like muscle, organ meats and bones.
Omnivores, on the other hand, can vary their diets more widely between plant- and animal-based foods. They have more complex digestive systems capable of extracting nutrients from many sources. While omnivores eat some meat, they do not require as high of a concentration of animal protein in their diet as carnivores.
Natural Diets
The natural diet of domestic dogs and cats can be determined by looking at the diets of their closest wild relatives – wolves for dogs and wild cats like lions for domestic cats. Wolves are carnivores and rely primarily on hunting large prey like deer, elk and bison for their nutrition. Up to 70-90% of their diet comes from meat and they have evolved as highly efficient hunters of large mammals.
Wild cats found in nature like lions, tigers and leopards are hypercarnivores, meaning over 70% of their diet consists of meat. They hunt prey ranging from large ungulates to small mammals and birds. Their digestive systems and dentition have evolved for efficiently catching prey and consuming raw meat. Domestic cats retain these hypercarnivorous traits, suggesting their natural diet should be high in animal protein and fat.
Dental Structure
Dogs and cats have teeth that are optimized for an animal-based diet. Their canine teeth are pointed, adapted for grabbing and tearing meat. Their premolars and molars have jagged edges that function like serrated knives to shear meat and sinew. The overall structure of their mouth and jaw is designed for the up-and-down motion needed to slice through flesh.
In particular, cats have 30 extremely sharp teeth. Their long canine teeth and the blade-like carnassials on the sides of their mouth are perfectly suited for capturing prey and slicing meat into small chunks that are easy to swallow. Their jaws cannot move sideways to grind plant matter, only up and down.
While dogs have slightly more varied teeth, they too have razor sharp front teeth and carnassials designed for shearing meat, tendon and skin. Their teeth tear and shred meat, rather than grinding plant material. The overall shape and dental structure clearly indicates dogs are carnivores.
Digestive Systems
Cats and dogs have different digestive systems that are adapted to their natural diets. Cats are obligate carnivores, meaning they must eat meat to acquire certain nutrients. Their digestive tracts are shorter than omnivores and herbivores to allow food to pass through quickly before it putrefies. Cats also have a highly acidic stomach pH of around 1-2 which helps kill bacteria from raw meat and break down proteins.
Dogs are facultative carnivores that thrive on an omnivorous diet. Their digestive tracts are longer than cats to allow plant matter to be sufficiently broken down and absorbed. Dogs also have a higher stomach pH around 4-5 that is more suited to digesting a variety of foods including starch. However, dogs still require a high amount of protein and fat in their diets compared to omnivores.
The differences in digestive anatomy and physiology demonstrate how cats thrive on an animal-based, high protein diet, while dogs can obtain nutrients from both meat and plant-based foods. But both require meat in considerable quantities to meet their nutritional requirements.
Nutrient Requirements
Both dogs and cats have bodies evolved for a carnivorous diet. They require high amounts of protein and fat, with minimal carbohydrates.
Cats are obligate carnivores, meaning they must eat meat as their primary food source. Cats need animal-based proteins to obtain essential amino acids like taurine, arginine, methionine, and cysteine. These amino acids are critical for eye, heart, reproductive system, and immune system health.
The Association of American Feed Control Officials recommends that cat foods contain at least 26% protein. Cats have a higher protein requirement than dogs. Commercial cat foods typically contain at least 30% protein, mostly from animal sources like chicken, turkey, lamb, fish and beef.
Dogs are technically omnivores, but their bodies thrive on a carnivorous diet. The minimum dietary protein recommendation for dogs is 18%. However, many veterinarians recommend feeding dogs a diet with at least 25-30% high-quality animal protein for optimal health.
Cats and dogs only require a minimal amount of carbohydrates in their diet. Commercial pet foods may contain carbs like rice, barley or corn, but these are not essential nutrients. Both species can meet their energy needs through protein and fat.
Commercial Pet Foods
Most commercial pet foods today are formulated to provide complete and balanced nutrition for dogs and cats. This means they are designed to contain all the nutrients pets need to thrive, in the appropriate proportions, when fed exclusively.
Dog and cat kibble contains protein from meat sources like chicken, fish, or lamb. It also includes carbohydrate sources like corn, rice, or wheat. Vitamins, minerals, fatty acids, and other essential nutrients are added as well. Meats used in pet food are by-products like organ meats, as well as muscle meat. Many brands nowadays focus on high-quality ingredients with more easily digestible carbohydrates.
In addition to kibble, there are also wet/canned foods, semi-moist foods, freeze dried, and fresh/refrigerated options. Canned pet foods typically have a high moisture content and may contain chunks of meat in gravy or sauce. All forms of commercial pet foods must meet nutritional standards set by the Association of American Feed Control Officials (AAFCO).
While home-prepared diets can also provide balanced nutrition, commercial pet foods offer convenience for most owners. They are formulated specifically to provide complete nutrition without any guesswork. Following package feeding guidelines is important, however, especially for puppies and kittens who have higher caloric needs.
Raw Food Diets
In recent years, there has been a growing trend of feeding dogs and cats a raw food diet. This involves preparing raw meat, bones, fruits, vegetables, and other ingredients and feeding them to pets instead of commercial kibble or canned foods.
Advocates of raw diets argue that this mimics what dogs and cats would eat in nature. They believe raw foods are more species-appropriate and contain more nutrients than processed commercial pet foods. Proponents say raw diets can improve a pet’s skin, coat, teeth, digestion, immune system and overall health.
However, raw diets are controversial. Skeptics argue there is limited scientific evidence to support the claimed benefits of raw feeding. They point out potential risks like bacterial contamination and nutritional imbalances if not properly formulated. Some veterinarians actively discourage raw diets due to safety concerns, especially for puppies and kittens.
Despite divided opinions, the popularity of raw pet food continues to increase. Consumers are attracted to the idea of fresh, natural ingredients. But experts caution that raw diets should be pursued carefully under veterinary supervision to ensure pets’ nutritional needs are fully met.
Veterinary Guidance
According to veterinarians, dogs and cats are classified as obligate carnivores. This means they require a meat-based diet to thrive. Vets recommend feeding pets a diet high in animal proteins and fats to provide complete nutrition.
While dogs and cats have adapted over centuries to eat some plant materials, vets caution against switching to a vegan or vegetarian diet. Without a high amount of animal-based proteins, cats and dogs may develop nutritional deficiencies leading to health issues.
Veterinarians advise pet owners to feed a balanced commercial diet formulated specifically for dogs and cats. Homemade raw or cooked diets may be unbalanced without the right mix of nutrients. Vets can help create customized meal plans for pets with special nutritional needs.
Overall, vets emphasize selecting high quality pet foods with meat or fish as the first ingredient. Monitoring pet health through annual checkups allows vets to ensure your dog or cat is getting proper nutrition from its diet.
Owner Experiences
Many pet owners have years of first-hand experience feeding both dogs and cats. Their observations and insights provide a valuable supplement to scientific research on canine and feline nutrition.
Sandra from Kansas City says, “I’ve had dogs my whole life and they’ve always done well on a mix of dry and wet dog food. But my cat Ming absolutely thrives on a raw meat diet. She’s 15 years old now and still extremely active and healthy.”
James in Seattle remarks, “I started feeding my Labrador retriever, Buddy, a homemade raw diet last year. He shed less, had more energy, and his coat became very soft and shiny. I’m convinced now that raw meat is ideal for dogs.”
Laura, a veterinary technician in Denver, comments, “In my experience, most healthy dogs and cats do perfectly fine on high-quality commercial pet foods, whether dry, wet, raw, or home-cooked. The key is picking a diet tailored to your pet’s age, breed, and any special health conditions.”
These perspectives demonstrate how different diets can work for different pets. Owners should consult with veterinarians to determine the optimal nutritional approach for the unique needs of their dog or cat.
Conclusion
Based on the evidence presented, both dogs and cats display strong signs of being obligate carnivores. Their dental structures, digestive systems, and nutrient requirements are all optimized for meat consumption. While dogs and cats can technically survive on some plant materials and commercial omnivore pet foods, these do not align with their natural anatomy and physiology. Their ideal diets most closely match those of wild carnivores, containing a high proportion of animal-based proteins and fats. Both veterinary guidance and pet owner experiences confirm that dogs and cats thrive best on meat-heavy diets that mimic their ancestral diets. In conclusion, the totality of evidence indicates dogs and cats are carnivores, not omnivores.